November 2016 - TACTICAL REVIEWS

Knife Review: Cressi Giant Knife and Alligator (Dive Knives 2016 – Detail Review)

24 November, 2016

This review provides further details for the Cressi Giant Knife and Alligator which could not be included in the Dive Knives 2016 – Mega Test Review

The candidates sent by Cressi were a last minute addition to the Mega Test Review, so unfortunately did not go on the Ionian Sea trip and missed out on some of the real use testing, however they did go through all of the experimental corrosion and cutting testing.

A pretty unique pair from Cressi with a knife at at each end of the size spectrum.

The Blade and Handle Geometry:

Most knife specifications have a basic description of the blade geometry, but in this section I will be taking a more detailed look at geometry and balance.

Using a set of gauges and precision measuring equipment including a Vernier protractor, callipers, fixed radius gauges and the unique Arc Master adjustable radius gauge (the one that looks like a crossbow).

These measurements have been tabulated and are presented along with other blades.

Key aspects such as the primary bevel angle, grind type, blade depth, blade thickness, length, weight are detailed, along with balance information.

The ‘Balance relative to the front of the handle’ tells you if the knife will feel front heavy, or if the weight is in your hand (a positive value means the weight is forward of the front of the handle). The ‘Balance relative to the centre of the handle’ indicates how close to a ‘neutral balance’ the knife has in the hand.

In the case of full convex grinds the approximate centre of the grind is used for the primary bevel angle estimate.

The measurements are presented alongside some of the other knives from the Dive Knives 2016 – Mega Test Review

A few more details of the Giant Knife:

Very nicely presented in its transparent box, the Giant Knife is clearly exactly what it says it is.

The knife and sheath come with a pair of rubber straps.

Standard belt buckle type straps are used.

The back of the sheath is basically flat.

One set of strap mounting points and what looks like an upside-down “CE” mark.

Near the top of the sheath are the other set of strap mounting holes. Something that has me curious is that the rubber retaining ring fits into a hole right at the top of the sheath, but there is an identical hole slightly further down. This could not be used for the retaining ring as you would never get it to fit over the handle, so is there another knife that uses this same sheath?

Staying with the old-school concept, the Giant Knife has a rubber retaining ring which is pulled over the hammer pommel.

Very neatly put together, the rubber ring has a tab which is easy to grip.

In the released position the rubber ring is pushed out of the way. Like this the knife is just loose in the sheath and can fall out.

The sheath is a one piece moulded plastic design.

And there is that substantial blade. Perhaps not actually ‘giant’, but this is certainly a BFK.

As we all know, ‘stainless’ really means ‘stain-resistant’ and Cressi have given the blade a black coating which helps with corrosion resistance, though the cutting edge itself cannot be coated.

Clearly marked as being made from 304 Stainless Steel.

Incorporated into the blade spine is a line cutting hook. This angle clearly shows how wide the double bevel angle is (also see the parameter table) which unfortunately makes it very ineffective.

The back of the blade also has a long line of serrations which unfortunately are also a double bevel with a very wide angle which limits their effectiveness.

A view of the ricasso and plunge line.

Being a true dive knife, the Giant Knife can be taken apart to clean and maintain the knife. The steel hammer pommel unscrews.

After taking off the pommel, the handle slides off the tang. The full tang has been given the same black coating as the blade, so reduces the need to disassemble and clean it.

Even the thread is coated, but given a few disassemblies this will wear off.

A few more details of the Alligator:

Switching to a completely different concept to the Giant Knife, we have the Alligator.

Being a much smaller knife, this is designed to be fitted to your BCD or belt and not to your arm or leg, so instead of rubber straps you get a mounting kit.

The mounting kit includes a hose mount with hose shim (for smaller hoses) plus a straight bar for fitting around webbing.

In the moulded plastic sheath is a sprung knife-retaining plate which clicks into place on the knife handle to hold it in place.

On the back of the sheath are the screw points for attaching the various mount options.

Is it a knife? Is it a pair of shears? Actually it is both.

Viewed from the other side it looks a bit more knife like.

At the base of the handle is a metal loop which holds the two parts of the handle together.

Flipping the clip outwards frees the handle to open up.

As you might expect with smaller shears the pivot is sprung loaded to make them easy to use.

Inside the handles is a set of gripping teeth that can be used to grip and twist nuts/bolts and other objects you need more grip for.

And there we have them, the Alligator’s jaws. Anyone having to cut loose lines underwater will know just how effective shears are for this task.

Also included is a line cutting hook.

A close view of the knife point. Though not a needle sharp point, I prefer the tip not to be too sharp for a diving knife.

The spine of the ‘knife’ (the top jaw of the shears) has serrations cut into it.

The serrations are formed from a single bevel.

Looking at the top jaw of the shears, the grind is very clean and precise.

One side of the pivot bolt has a security type nut. To tighten this you need a flat head screwdriver with the middle ground out. On trying to adjust this it appears that either thread-lock or some other method has been used to hold this nut in place, so I’ll be leaving it until it needs adjustment.

You can sheath the Alligator either way round, however one way is easier than the other.

The reason it is easier to sheath the knife one way round is due to the blade being offset.

Looking closer you can see that the offset allows the spring for the shears to be incorporated. You can also see the plastic scrapings on the pivot nut where it has rubbed on the sheath.

Feature packed and very versatile.

What are they like to use?

There are those that say there is no need for a big diving knife any more. For many this may be true, and they are better served by something smaller, or even just a line cutter, but there is still a place for the BFK when you need a tool that can take on bigger tasks. Cressi recognise this and that is why they have recently introduced the Giant Knife.

This review includes a cutting tool from both ends of the size spectrum with the much more compact Alligator which is a pair of shears as well as a knife. The Alligator is supremely effective for cutting and in the cutting tests has been scored separately as both a knife and as shears. The cutting score for the shears was joint first place, and the knife was not a bad performer at all. If you combined both scores, it is head and shoulders above any other knife in the Mega Test. The Giant Knife was a respectable performer, but the cutting hook and serrations were poor. See the Dive Knives 2016 – Mega Test Review for more information on the cutting test results.

For stainless steel tools, both Cressi knives came out of the corrosion test very well. There is a small amount of rust showing near the pivot between the two halves of the shears.

There is also some rust on the gripping jaws inside the handles.

For the Giant Knife, there is nothing to show for the corrosion testing as there was no visible rust to be found on the knife.

Going back to the Giant Knife… Oh yes, this is a BFK! If you want a decent sized diving knife then the Giant Knife is a very good fit. It is big, the blade is thick, it is heavier than most, but you have a heavy duty tool you can really put to work. The shaped rubber handle gives you a very positive grip and lets you go for it. With some weight behind it, the hammer pommel is effective (just watch where that point is going).
(For size reference, I wear XL size gloves).

Going the other way now, and as the Alligator is much more compact than the Giant Knife, the grip is nearly (but not quite) too short. Despite the smaller size, the Alligator’s knife is effective in all its aspects, with the cutting hook working well and serrations working reasonably.

But the jewel in the Alligator’s crown are the shears. Wet lines and rope can be very difficult to grip and cut with a knife. Free-floating lines even worse, but shears grip the line for you, making it so much easier to cut. Notice how the tip of the shears in the knife blade is hook shaped, which prevents lines slipping out of the front of the jaws. Being spring loaded makes the shears stay firmly in the hand as you use them. Even without the knife blade elements of the Alligator, it would be worth having just for these shears.

Review Summary

The views expressed in this summary table are from the point of view of the reviewer’s personal use. I am not a member of the armed forces and cannot comment on its use beyond a cutting tool or field/hunting knife.

Something that might be a ‘pro’ for one user can be a ‘con’ for another, so the comments are categorised based on my requirements. You should consider all points and if they could be beneficial to you.

_______________________________________________	_______________________________________________
Things I like	What doesn’t work so well for me
_______________________________________________	_______________________________________________
The Alligator gives you the cutting power of shears as well as a knife blade.	Neither design is safe for ‘release’ cutting next to the body.
The Giant gives you a true heavy duty ‘BFK’ for diving.	The Giant Knife’s serrations and hook are ground at far too wide an angle to be effective.
Extremely good corrosion resistance.	The Alligator handle catch can be tricky to open, especially with gloves on.
Both ends of the size spectrum are represented.
Sheaths work right or left handed.

Discussing the Review:

Please feel free to add comments to the review, but the ideal place to freely discuss these reviews is on a forum. If you started reading the shorter forum version of the review, but followed the link this full exclusive review, please return to that forum to discuss the review there.
If you read the review entirely on Tactical Reviews, please consider one of the following to join in any discussion.

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Knife Review: Whitby & Co Dive Knives – DK9, DK11 and DK511/14 (Dive Knives 2016 – Detail Review)

21 November, 2016

This review provides further details for the three Whitby & Co Dive Knife models DK9, DK11 and DK511/14 which could not be included in the Dive Knives 2016 – Mega Test Review

The Blade and Handle Geometry:

Most knife specifications have a basic description of the blade geometry, but in this section I will be taking a more detailed look at geometry and balance.

These measurements have been tabulated and are presented along with other blades.

Key aspects such as the primary bevel angle, grind type, blade depth, blade thickness, length, weight are detailed, along with balance information.

In the case of full convex grinds the approximate centre of the grind is used for the primary bevel angle estimate.

The measurements are presented alongside some of the other knives from the Dive Knives 2016 – Mega Test Review

There are three Whitby knives, and these have been logged across two comparison tables.

A few more details of the DK9:

Before we really get going looking at the details, you might be curious as to these being Whitby & Co knives yet coming in alternately branded packaging. Whitby & Co source some of the foremost international brands and supply Trade customers with these products.

The knives on test here are referred to under their Whitby & Co model numbers.

Starting with the smallest of the Whitby dive knives, the DK9, it is supplied with two rubber straps with quick release buckles and a leaflet.

On the back of the box are the instructions for assembling the straps. This is the same for all the models on test here.

One end of the rubber strap is moulded so that it won’t pull through the buckle.

Onto the DK9 itself, this is exactly as it comes out of the box, in its sheath.

The knife construction is a single piece of flat stock steel. Being a typical dagger design with shapr point and double edge, it has no diving safety features that would make it safe for cutting away entanglements from the body.

The sheath consists of two moulded plastic halves riveted together. Each side has a slot to fit the rubber straps into.

At the top of the front piece of the sheath are a couple of plastic hooks which hold the DK9 in the sheath.

With the knife inserted you can see how the plastic hooks fit over the guard.

The back of the sheath is a simple flat plastic surface.

Let’s start looking round the knife. From this overall view, notice that in the handle and blade are two types of shackle wrench cut-out and the knife is a one piece all metal construction.

Having a typical dagger grind, there are no sharp corners/edges to the plunge lines.

One side of the double edged blade has some very effective serrations.

The serrations are formed with a single bevel, so when looking at the back, there is no visible edge bevel.

Quick close-up of the blade tip.

A generous sized lanyard hole is included in the handle.

It is a relatively compact blade, and despite the thin handle is comfortable enough in the hand (I take XL gloves).

There is room to fit both straps, but being so compact I found I only needed one and it stayed where I needed it.

As quick-release buckles are used, you set the strap length to fit at which point they operate as fixed length straps. This is how the rubber is threaded through the adjustment side of the buckle.

A few more details of the DK11:

Taking a step up in size to the DK11, and we also take a step up in design and function. As with the DK9, the DK11 comes with two straps with quick-release buckles.

A more substantial package than the DK9. Note that there is a sliding lock for the knife release lever.

Box fresh and not yet subjected to the corrosion testing, the DK11 has a double edged blade with a line cutting hook.

On the front of the sheath is a sprung knife retaining catch with a hook that engages with the knife handle.

Requiring a reasonable pressure, the retaining catch lifts away to release the knife.

The two halves of the plastic sheath are screwed together.

The spine of the blade has the serrations and cutting hook, and the DK11 also has a hammer pommel.

At the front of the handle a stainless steel curved guard is incorporated. There is what might be considered a finger choil in the ricasso, but this is not something I would use when diving.

A close-up of the blade tip and factory edge.

The serrations are a similar pattern to the DK9, but have three repeats of the smaller groove rather than two.

Just as with the DK9, the serrations are formed with a single bevel, so from the other side have no visible bevel.

A line cutter hook is included near the guard.

Despite its smooth lines, the handle is nice and grippy thanks to being rubber.

The blue plastic insert includes the knife retention catch point.

With the DK11 you have a good mid-sized all rounder blade.

After threading the straps through the sheath, you still need to thread the loose end through the buckle.

A few more details of the DK511/14:

Lastly we have a bit of an old-school BFK (Big F’n Knife), the DK511/14. As before, there are two adjustable quick-release buckle straps included.

This is what the classic dive knife used to look like, and it still has a place today.

Again with the classic design we have a rubber ring fitting over the end of the handle to keep the knife in the sheath.

To release the knife just pull the ring off the handle using the tab provided.

Definitely not a compact blade, this is a full size traditional dive knife design.

A real working blade, there are several useful features.

Very ‘saw-like’ serrations which shred rope, even if not cutting it cleanly.

A close-up of the tip shows it could do with a little work, but actually not having a needle like point is safer for diving.

Unlike the hook type of line cutter, the DK511/14 has a much bigger line cutting feature with an elongated scallop which helps contain what you are cutting by preventing the line/rope from slipping off the cutting edge.

The handle is coffin shaped with a flared butt and guard.

Yeah, this is a BFK!

You have a couple of options for strap positions, and the back of the one-piece sheath is shaped to fit your leg.

What are they like to use?

By featuring these three models, this review covers a wide range of the styles of knife offered by Whitby. Not to be too generalistic I would class these three as a backup, general purpose and heavy duty type of knife.

I’ll not cover the cutting again as this is detailed in the Dive Knives 2016 – Mega Test Review which you can check for more information on the cutting test results.

None of these dive knives has a blunt tip, which means you do need to take great care using them as a release knife. All of them also have double edged designs which again makes them very hazardous for release use especially if you have line or rope wrapped round you.

Price-wise the DK9 and DK511/14 come in at the low end of the scale, and the DK11 entering the low-mid price range. This is an important consideration as though not perfect, these have proven to be very good value.

Remember that the corrosion testing was tantamount to abuse for these knives. No cleanup, and no protection for the blades, just a highly corrosive environment.

Starting with the DK9, unsurprisingly, the rust has taken hold inside the sheath, and where the edge has been ground (leaving a rougher finish than the rest of the knife). With only two spots suffering significantly, very little of the cutting edge was damaged by this corrosion.

Next up the DK11. Though this does not look too bad, there is rust going into the handle, and around 30% of the edge has corroded. After re-sharpening this knife is was clear the edge had pitted and become damaged. The serrations however show no signs of rust and were unaffected.

Lastly the DK511/14 which was looking one of the worst. It was also the first to show signs of rust after only two hours immersion. The mirror finish on the blade has helped protect it, but the edge has suffered quite a lot of corrosion and pitting.

These knives definitely need a little care and attention and should be cleaned and have grease applied to protect the blades.

Of the three, the DK9 felt very appropriate as a forearm mounted backup blade. Small, easy to forget you are wearing it, and importantly, being on the arm it is easier to watch as you re-sheath it – that point is wicked and will bite you if you are not careful.

The retention system was the least easy to use as you pretty much had to drag the knife out and push it home like a friction fit. Getting gloved fingers under the plastic clips was unreliable.

Going to a leg mount with the DK11, on dry land, the knife release catch was the stiffest of all the sprung clip designs and I thought it would make things a struggle in the water. It was much easier to work with once strapped to your leg, but still not as easy as I would really like. One winning, and unique, feature is the sliding lock. It really did give peace of mind to know that the blade was positively locked into the sheath, and unlocking to then allow the blade to be released was easy.

Lastly the DK511/14 which takes up much more room on your leg. With the rubber retaining ring pulled off the knife handle, the knife actually rattles around in the sheath and will fall out if the sheath is tipped up. This is unlike the other two where simply fully inserting the knife will lock it into the sheath – you have to watch this and make sure you re-fit the rubber retaining strap. There is a time and a place for a big knife, and the DK511/14 gives you a lot of blade for the money.

Review Summary

_______________________________________________	_______________________________________________
Things I like	What doesn’t work so well for me
_______________________________________________	_______________________________________________
Excellent cutting results from the DK9	None of the models are safe for ‘release’ tasks due to sharp points a double edged blades.
The DK11 has a locking system to ensure the blade is secure.	All models suffered edge damage from corrosion.
Good value.	DK511/14 knife retention is fiddly to use.
Effective rubber straps.
Sizes from Compact to BFK to choose from.

Discussing the Review:

Please feel free to add comments to the review, but the ideal place to freely discuss these reviews is on a forum. If you started reading the shorter forum version of the review, but followed the link this full exclusive review, please return to that forum to discuss the review there.
If you read the review entirely on Tactical Reviews, please consider one of the following to join in any discussion.

EdgeMatters – Sponsored Reviews (UK based Forum for Knife Makers and Collectors)

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CandlePowerForums – Knife Reviews Section (Largest and Friendliest Flashlight Community Forum)

Knife Review: Promate Dive Knives – Barracuda, Scuba, Seal Folder, KF505 Blunt and Line Cutter (Dive Knives 2016 – Detail Review)

17 November, 2016

This review provides further details for the five Promate dive knives (Barracuda Blunt Ti, KF593 Ti, KF090 Seal Folder Ti, KF505 Blunt and KF001 Line Cutter) which could not be included in the Dive Knives 2016 – Mega Test Review. Promate is a Full line manufacturer of scuba diving equipment and snorkeling gear including regulators, instruments, buoyancy compensators, masks, snorkels, fins, knives, boots, gloves and bags.

The Blade and Handle Geometry:

Most knife specifications have a basic description of the blade geometry, but in this section I will be taking a more detailed look at geometry and balance.

These measurements have been tabulated and are presented along with other blades.

Key aspects such as the primary bevel angle, grind type, blade depth, blade thickness, length, weight are detailed, along with balance information.

In the case of full convex grinds the approximate centre of the grind is used for the primary bevel angle estimate.

The measurements are presented alongside some of the other knives from the Dive Knives 2016 – Mega Test Review

As there are five Promate cutting tools, these are logged across two tables.

A few more details of the KF001 Line Cutter:

There are five models from Promate and a huge amount of detail to cover, so each one will have its own “A few more details…” section.

The first two we will look at are the ones that are not fixed blade sheath knives, the Seal Folder and Line Cutter.

Fresh out of the box.

A small container is supplied with the line cutter.

This contains two spare blades wrapped in oil paper.

A close up of the blade in the line cutter.

Taking out the three screws holding the line cutter together allows you to see how the standard utility blade fits inside.

It is a generous size so is easy to handle.

A few more details of the KF090 Seal Folder Ti:

An adjustable wrist strap is supplied fitted to the Seal folder.

The pivot is riveted and cannot be adjusted.

On one side there is a plastic pocket clip.

From this side you can see the blade pivot and lock bar pivot rivet heads.

As a specialist knife, the Seal folder has an unusual cutting hook which is accessible even with the blade folded.

A closer look at the cutting hook.

The blade is part serrated and there is a small thumb opening hole.

In case you had forgotten, it is made of titanium. The serrations are well formed.

When you look at the reverse of the blade, you can see that this knife uses only a single bevel edge.

Going in closer to the back of the serrations.

And also the plain edge.

Not a large knife, the Seal folder is still a comfortable size.

A few more details of the Barracuda Blunt Ti:

Promate’s Barracuda comes in Steel and Titanium versions, as well as blunt and pointed tips. The fully diving orientated blade design with Titanium and a blunt tip was chosen for the review.

Supplied with the knife are two rubber straps and an instruction leaflet.

The strap has quick release buckles.

Each buckle has a sprung loaded adjustment clip to grip the rubber strap.

A strap in its fully assembled state. However this now cannot be fitted to the sheath. You need to take it apart, thread it through the slots and then reassemble it.

Before unsheathing the knife for the first time.

Inside the sheath the blade is wrapped in plastic.

With the knife out, you can see the ambidextrous retention clip.

The retention clip is a sprung plate with a catch in the centre and a release button each side.

A quick look at the back of the sheath.

A fully featured blade made of titanium which has a cutting hook, plain edge, prying blunt tip, smaller plain edge leading into a section of large serrations.

Clearly marked as being made of titanium.

A cutting hook is included near the handle.

The blunt tip is shaped nicely for prying, tapered but not too thin at the end.

Contoured more heavily than any of the other handles, the Barracuda provides excellent grip in all conditions.

Just at the guard area is the indentation that the retention clip holds on to.

The back of the blade reveals that the serrations are cut with a single bevel, but the plain edges are double bevelled.

Nicely cut, the serrations are larger than any others I’ve used.

For scale, I take XL size gloves.

The butt has a large hammer striking surface. This is made of Titanium, so is not up to very heavy work.

Though it doesn’t need any cleaning for corrosion prevention, the Barracuda does fully disassemble.

As mentioned earlier, the straps need to be threaded through the loops before fitting the quick release buckles.

Fully assembled and ready for work.

A few more details of the KF593 Ti:

This is a knife which has had a little more exposure than most and you might recognise it as it was featured in a few episodes of Bear Grylls ‘Man vs Wild’. It is also known unofficially as the Promate ‘Scuba’ Knife, but officially only as the KF593. There is a blunt tip version as well.

The KF593’s box.

Inside the box the knife comes wrapped in plastic. Also include are two rubber straps.

With the wrapping off. There is a warning card included regarding care for the knife, however, this advice proved unnecessary.

The KF593 fresh out of the box.

One of the great features of the KF593 is the retention system of the sheath. There is a sprung plate with two release buttons and a catch.

Looking at the back of the sheath, you can see the lower strap loop serves as a drainage hole. there is also a plastic spring which pushes against the blade when it is in the sheath the prevent rattling.

This knife has alternative colour options for the handle. The orange part of the handle can be grey or blue.

In case you forget, this is a titanium blade. Being a dive knife there is a line cutter hook.

An unusual ‘reverse’ set of serrations are on the blade spine.

The full tang protrudes through the handle and provides a narrow hammer.

As supplied, the factor edge looks quite coarse, but cuts well enough.

A nice mid-sized knife. (I take XL size gloves.)

The coloured rubber insert gives a good amount of grip.

Rather than quick release buckles, this knife uses belt buckle type fastenings. Note that the holes in the strap are actually filled in. The first time you use any of them you need to push the buckle prong through the rubber in the hole.

These straps are very quick and easy to set up and use.

A few more details of the KF505 Blunt:

And onto the last one of the Promate knives, the steel bladed KF505.

In the box is the sheathed knife, rubber straps, care instructions and disassembly instructions.

The clear sheath is an option for this knife.

A box-fresh KF505.

Compared to the titanium knives a different sheath retention system used. A single release button on the front of the sheath is connected to a catch at the rear.

Before moving onto some details let’s look at both sides of the blade.

The other side of the blade.

An unspecified stainless steel is used for the guard. Check the corrosion results later.

The serrations are cut with a single bevel.

The use of a single bevel is clear when looking at the other side.

A line cutting hook is ground into the blade near the handle. Note the steel designation on the blade – Stainless Steel 420 J2.

This knife uses a one-piece rubber handle.

The tang nut acts as a hammer.

Starting to disassemble the knife by taking the tang nut off.

And fully disassembled.

The rubber straps have standard belt buckle type fixings.

This design of strap make it very quick and easy to get everything put together ready for use.

Like the previous model this is a medium sized knife.

What are they like to use?

With several very different offerings from Promate, the cutting results were varied and also not as I expected. The best performer in the cutting tests was actually the Seal folder with Ti blade. This maintenance-free small titanium bladed folder makes a fantastic backup knife. The other knives were mainly let down in the cutting tests by the factory edges, and are more capable given a bit of work getting a good edge.
The biggest surprise was the performance of the dedicated line cutter; using only a standard steel utility blade as the cutting edge, the corrosion testing really took its toll on this (details to follow). With a new blade, initial tests were that this was a very good cutter, so if you can find stainless utility blades they would be a better option.
See the Dive Knives 2016 – Mega Test Review for more information on the cutting test results.

Though a really excellent cutter, the Seal knife had a small issue that was easily fixed, but one worth being aware of.
The sharp eyed might have spotted that when looking at the ‘H’ (where the blade spine and lock bar touch), the lock bar is slightly raised. This gave me concern over how well the lock would function. Proven correct, I found the lock failed under mild pressure to close the blade.

Taking a closer look at the locking surfaces, these appeared to be raw pressings so the fit was not good, and the blade tang hook was not catching the lock bar well. There is a simple fix for that….

Without having to take the knife apart, the blade tang hook can be cleaned up with a file (and the Ti files easily) to give a much better flat locking surface. Be careful not to go at this too much as taking more material than necessary will result in a blade that has play in the locked position. File a bit then test, and repeat. Once corrected, the locked blade was solid and the result was worth having to do this.

Earlier I mentioned the line cutter having disappointing cutting results, well this is why – Oh dear! The corrosion testing certainly hit the weak spot of this design – standard carbon steel blades. Cheap and easy to replace, but the rust starts as soon as it gets wet.

The corrosion tests threw up a surprise with the stainless steel knife. Typically, non-cutting stainless parts have a higher grade of stain resistance (with lower cutting ability), but in this case the worse corrosion was to the guard (though the hammer pommel was completely free of corrosion). The blade had a light frosting, but the guard was heavily corroded. After a cleanup, the guard was found to have deep pitting, and the clean-up (using a soak in cider vinegar) actually etched the guard heavily while making the blade nice and shiny.

The blade itself was relatively untouched and the frosting cleaned off with vinegar.

Ergonomics of the Promate knives is excellent, with easy to use, and secure, sheath retention along with great straps.

Folders are a contentious subject for diving, as the action of opening can be a make or break moment for the diver. The opening hole in the Seal folder is a little small, and being experienced in one-handed-opening (OHO) I did find this to be perfectly usable even with gloves, but with tired, cold hands and very thick gloves I suspect it will become increasingly difficult. There is also the exposed cutting hook to consider. This hook was actually a very poor cutter as it was not very sharp as supplied; with it being exposed, this lack of sharpness is actually a benefit. The Seal’s blade is worth carrying this knife for, with very good cutting ability and excellent serrations.

Overall it is clear these Promate knives are designed very well for divers, and the added bonus of zero corrosion on the titanium blades make them well worth considering.

Review Summary

_______________________________________________	_______________________________________________
Things I like	What doesn’t work so well for me
_______________________________________________	_______________________________________________
Titanium blades require no post-dive cleanup.	The steel knife and cutter suffered corrosion.
Excellent blade retention.	Factory edges not very good.
Comfortable leg straps.	Serrations are too coarse for smaller ropes.
Handle design provides a very secure grip.
Sheaths are ambidextrous.

Discussing the Review:

Please feel free to add comments to the review, but the ideal place to freely discuss these reviews is on a forum. If you started reading the shorter forum version of the review, but followed the link this full exclusive review, please return to that forum to discuss the review there.
If you read the review entirely on Tactical Reviews, please consider one of the following to join in any discussion.

EdgeMatters – Sponsored Reviews (UK based Forum for Knife Makers and Collectors)

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Knife Review: Spyderco Assist Salt (Dive Knives 2016 – Detail Review)

8 November, 2016

This review provides further details for the Spyderco Assist Salt which could not be included in the Dive Knives 2016 – Mega Test Review

Not strictly a diving knife, thanks to the Assist model’s reputation as a rescue knife and the use of specialist rustless H1 steel in the ‘Salt’ edition, it has been adopted by many divers as an underwater rescue knife.

The Blade and Handle Geometry:

Most knife specifications have a basic description of the blade geometry, but in this section I will be taking a more detailed look at geometry and balance.

These measurements have been tabulated and are presented along with other blades.

Key aspects such as the primary bevel angle, grind type, blade depth, blade thickness, length, weight are detailed, along with balance information.

In the case of full convex grinds the approximate centre of the grind is used for the primary bevel angle estimate.

The measurements are presented alongside some of the other knives from the Dive Knives 2016 – Mega Test Review

A few more details:

The Assist Salt arrives in Spyderco’s standard box.

An instantly recognisable design, but now in a bright yellow FRN and with H1 proudly shown on the blade. You will notice the Assist model’s ‘cobra hood’ over the thumb hole is not present on the Salt version.

Spyderco’s very grippy FRM scale pattern surrounds the model and logo.

And why not? There is a whistle moulded into the handle.

A Spyderco wire clip is used. This can be fitted to either side of the handle.

The ends of the wire clip are held in place under a special hollow bolt that also provides the lanyard hole.

At first it looks like the cutout in the lock bar is misaligned, but….

…no, this is one of the Spyderco details where due to the pivoting action of the lock bar, the cutout does line up once pressed in to release the lock (or due to opening the blade).

The Assist uses a mostly serrated edge (80%), but with a small section of plain edge for detailed tasks. The main cutting power of the blade is in those SpyderEdge serrations.

With well formed finger grooves and the textured FRN handle, the Assist Salt is not short on grip.

Yes, that is H1 steel.

For those not familiar with the Assist model, we’ll come back to the grooves in the blade spine.

Recessed into the butt of the handle, there is a point that looks like a glass breaker.

With the blade closed, if you give it a squeeze, the glass breaker point comes out of the handle ready to use.

Inside the handle where the blade tip sits, there is a small sprung block which has the glass breaker in it.

The rounded end of the blade presses into this block and pushes the glass breaker out for use. Very neat design.

What it is like to use?

Being a folder, for use as a dive knife, it is important that the Assist is a good size as this makes it easy to handle with, and without, gloves.

Actually in terms of easy handling, this is where I was slightly disappointed with the Salt version, as for some reason Spyderco decided to do away with the ‘cobra hood’ over the thumb hole. The thumb hole is still big enough to make opening easy enough, but that cobra hood would have made all the difference when using wet gloves with cold hands, just giving you more to get hold of.

With the claims about H1 steel, I was particularly interested to see the corrosion test results. What did surprise me was what looked like a failure in this regard. However looking much closer, the apparent corrosion is actually the black writing on the blade which has mostly disintegrated, but where the black ‘1’ was, it has made it look like the blade has rusted. However this can be cleaned off leaving just the H1 steel. It might be better for Spyderco to use a different ‘ink’ for the writing, or none at all, to avoid this blemish on the otherwise unmarked H1 steel.

The distinctive blade is a good size (I take XL size gloves) as can be seen here. This is ideal as you have plenty of edge to work with combined with the safety of the blunt tip to prevent stabbing yourself (or others).

To give an idea of scale, here it is next to the Fällkniven F1 and a Spyderco UK Pen Knife.

We have already seen the hidden glass breaker and how the finger grooves in the blade spine are used to access this, but there is another design feature that these finger grooves provide. The Assist can be used as a type of shears where the material to be cut is placed under the folding blade and the blade then squeezed shut to complete the cut. In this arrangement, you are carrying out a push cut with a serrated blade, when the serrations work best in a sawing motion. Personally, despite the very sharp blade, I found this to not work well on wet rope, in fact a normal cut worked far better, so for me the jury is out on that feature.

Unsurprisingly the SpyderEdge was an excellent cutter, and the H1 steel held up well. See the Dive Knives 2016 – Mega Test Review for more information on the cutting test results where the Assist achieved the second highest score.

Personally for a ‘working’ diving knife I prefer a fixed blade, but as a backup/release knife, the Assist gives me real confidence when carrying it. Requiring little to no care or maintenance, the Assist Salt is just ready and waiting for when you need it.

Review Summary

_______________________________________________	_______________________________________________
Things I like	What doesn’t work so well for me
_______________________________________________	_______________________________________________
Proven Escape Knife Design.	The Assist ‘Cobra Hood’ is not on the Salt version.
H1 ‘Rustless’ Steel.	Blade marking corrode (even though the steel doesn’t).
Built-In Signal Whistle
Built-In Glass Breaker.
Excellent grip.

Discussing the Review:

Please feel free to add comments to the review, but the ideal place to freely discuss these reviews is on a forum. If you started reading the shorter forum version of the review, but followed the link this full exclusive review, please return to that forum to discuss the review there.
If you read the review entirely on Tactical Reviews, please consider one of the following to join in any discussion.

EdgeMatters – Sponsored Reviews (UK based Forum for Knife Makers and Collectors)

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Knife Review: Benchmade 112S H2O (Dive Knives 2016 – Detail Review)

7 November, 2016

This review provides further details for the Benchmade 112S H2O which could not be included in the Dive Knives 2016 – Mega Test Review

The Blade and Handle Geometry:

Most knife specifications have a basic description of the blade geometry, but in this section I will be taking a more detailed look at geometry and balance.

These measurements have been tabulated and are presented along with other blades.

Key aspects such as the primary bevel angle, grind type, blade depth, blade thickness, length, weight are detailed, along with balance information.

In the case of full convex grinds the approximate centre of the grind is used for the primary bevel angle estimate.

The measurements are presented alongside some of the other knives from the Dive Knives 2016 – Mega Test Review

Please note the Benchmade 112S is incorrectly named the 112B in the table.

A few more details:

Benchmade’s nicely presented box.

Taking the lid off the box gives your first view of the sheathed model 112S H20 diving knife.

Included are the sheathed knife, a single rubber strap and a leaflet.

The strap, which can be used for a calf strap or arm strap has a quick release buckle.

A closer look at the plastic buckle and the rubber strap’s adjustable and fixed ends.

The sheathed 112S H2O is a very neat package.

There is an essential drainage hole at the bottom of the sheath.

On one side of the sheath is a very neat and functional release lever which holds and release the knife.

Looking in a bit closer you can see the metal pivot made of 316 Stainless Steel and hidden inside is a zinc-plated music wire spring.

And here it is, the 112S H2O knife.

Featuring a blunt tip designed for safety and prying, there is a plain edge near the tip and a serrated edge closer to the handle.

Two sizes of scallop are used for the serrations.

The plunge line is nicely radiused to avoid stress concentrators, especially important as the blade is designed to pry.

A first finger indentation combined with a grippy rubber handle, makes the 112S very sure in the hand.

Surprisingly missing from some dive knives, the 112S has a lanyard hole.

On the spine is a small protrusion; it is this that the retaining clip locks onto to keep it secure in the sheath.

Part of what makes the 112S look strange, but yet which gives it its excellent cutting power is the chisel grind used for the main edges. This is the back of the blade and it is essentially just flat steel.

The rear of the serrations.

And of the plain edge.

Also included in the blade design is a line cutter hook. This too is a chisel grind and is cut the opposite way to the main edges (back to front instead of front to back).

Looking along the blade from the flat side.

What it is like to use?

Coming from a well respected knife manufacturer, the 112S had a lot to live up to. One of the stranger looking knives, it might not be one which you drool over and ‘must have’. However there is purpose behind every design detail, and its cutting test results speak for themselves. Only shears equalled the cutting score of the 112S, that is quite some achievement. See the Dive Knives 2016 – Mega Test Review for more information.

Another key feature of the 112S is the sheath and the retention system. As long as you mount the sheath so that your hand falls onto the handle and your thumb onto the release lever, the drawing of the knife becomes completely natural. Your thumb presses the lever as you grip the knife and the knife can be easily withdrawn. I have found that if pulling on the knife too early, the release lever can’t ‘let go’ of the knife and you have to push the knife back into the sheath to allow it to release the lock. I particularly like that there is a slight friction fit of the knife into the sheath, so even with the lock released, it doesn’t just fall out.

For a good knife steel (N680), the 112S performed very well in the corrosion testing. Here is the raw result of this testing, but actually a lot of this rubbed off with a cloth, leaving only really the outer ring of the corrosion. Less easy to see, there is some corrsion near the handle rubber, but overall for what really constitutes complete neglect, the 112S did not suffer any significant corrosion.

One concern I had was about only a single strap being provided, and this was for two reasons. Firstly was comfort of fit – with two straps you don’t need either to be too tight, but secondly and perhaps more importantly, in case a strap snapped, was cut, or became snagged on something, once that single strap has failed you could lose the knife.

However, my concerns over comfort proved not to be realised at all, and the strap is a good quality so felt secure enough. As long as you check its condition regularly it should be reliable.

In the Dive Knives 2016 – Mega Test Review I did express a preference for one of the knives on test, but that was in relation to a general purpose backup knife. If I were expecting a lot of cutting work, then the Benchmade 112S would jump right up there and would be my pick of the bunch as a quality cutting and prying tool.

Review Summary

_______________________________________________	_______________________________________________
Things I like	What doesn’t work so well for me
_______________________________________________	_______________________________________________
Excellent cutting performance.	Only a single leg strap.
Great ergonomics for knife and sheath.	Slight concern over the corrosion resistance of the ‘music wire’ spring used for the sheath lock.
Sheath is easy to use and secure.
Strong prying tip.
Very good corrosion resistance.

Discussing the Review:

Please feel free to add comments to the review, but the ideal place to freely discuss these reviews is on a forum. If you started reading the shorter forum version of the review, but followed the link this full exclusive review, please return to that forum to discuss the review there.
If you read the review entirely on Tactical Reviews, please consider one of the following to join in any discussion.

EdgeMatters – Sponsored Reviews (UK based Forum for Knife Makers and Collectors)

BladeForums – Knife Reviews (US based Forum for Knife Discussion)

CandlePowerForums – Knife Reviews Section (Largest and Friendliest Flashlight Community Forum)

Dive Knives 2016 – Mega Test Review

6 November, 2016

Knife blades and seawater are usually something I do my best to keep apart, but when diving a knife must survive some of the most hostile conditions and its performance can be a matter of life and death.

This Mega Test Review brings together twelve knives from five leading knife brands and puts them to the test in real world conditions covering geometry, corrosion resistance, ergonomics and wet cutting performance, as well as comparing steel to titanium, serrations to plain edges, fixed blades to folders and dedicated line cutters to standard knife blades.

The selection of knives was specifically put together to show as many different aspects as possible and considerations which could be applied to knives not in this review.

Here we go!

The contenders:

First up, the contenders one by one. Due to the sheer size of the Mega Review and the testing, I’ve had to create are additional supporting reviews, knife brand by knife brand, concentrating on some more specific details of each knife. These are now all completed and can be found through the following links:

Benchmade 122S H2O – REVIEW ONLINE
Spyderco Assist Salt – REVIEW ONLINE
Promate Barracuda Blunt, KF593 Ti, KF090 Seal Folder Ti, KF505 Blunt, KF001 Line Cutter – REVIEW ONLINE
Whitby DK9, DK11, DK511/14 – REVIEW ONLINE
Cressi Giant Knife, Alligator – REVIEW ONLINE

These are the ones that arrived before a diving trip to the Ionian Sea.

The last minute entries which unfortunately didn’t get to travel as much.

The following photos are of each knife tested.

Benchmade 122S H2O

Correction: in the data tables later in the review the 112S is incorrectly named the 112B.
The H2O fixed was originally developed for an elite military program. The knife features a blunt tip, opposing bevel for torsional strength and an integrated cutting hook.
Blade Steel: N680 (57-59 HRC)

Spyderco Assist Salt

Not specifically a dive knife, the Assist Salt combines the multi-functional versatility of the Assist model with the rustproof qualities of H-1 steel. The defining feature of the Assist Salt is its H-1 steel blade and lock bar. This material uses nitrogen instead of carbon to create a steel that is tough and completely immune to corrosion.

Promate Barracuda Blunt

Made for the professional diver, the Barracuda has a Titanium blade and Titanium hammer on handle bottom. There are quick-release adjustable straps, and though the knife is easy to disassemble it requires little or no maintenance.

Promate KF593 Ti

Designed by scuba diver’s for scuba divers, the light weight Titanium blade with easy-grip rubber molded handle requires little or no maintenance. The full tang protrudes through the handle providing a narrow Titanium hammer on the handle bottom.

Promate KF090 Seal Folder Ti

Light weight Titanium bladed folder requiring little or no maintenance with an adjustable lanyard for easy carrying.

Promate KF505 Blunt

Using a 420 stainless steel blade there is a hammer on the handle bottom and easy-grip rubber handle. The KF505 is easy to disassemble for cleaning and maintenance.

Promate KF001 Line Cutter

Heavy-duty line cutter with easy hold handle. Disassembles to replace the blade and includes 2 replacement blades (standard utility knife blades).

Whitby DK9

2.75” Stainless steel double-edged serrated/plain blade and Stainless steel handle.

Whitby DK11

The Whitby Divers’ Knife DK11 features a double-edged blade with one edge being serrated and the other is a fine edge. In addition to its multi-purpose blade, the Whitby Divers’ Knife DK11 features a hammer hilt, situated within the rubber handle.

Whitby DK511/14

This Diver’s Knife has a 6.25-inch stainless blade and an overall length of 11 inches. The handle of the Whitby Diver’s Knife DK511/14 is contoured moulded black plastic and the knife is supplied with a plastic sheath with arm/leg straps. A big, traditional, diving knife design.

Cressi Giant Knife

This knife has large dimensions that make it particularly effective during use. Perfect as a work tool or for particularly intensive use. Featuring a Japanese 420 Stainless Steel blade with black coating treatment for corrosion resistance.

Cressi Alligator

The CRESSI Alligator is a unique tool offering the function of a Knife and Scissors. The 420-Stainless Steel Blade has a Straight and Serrated Edge plus a cutting hook and shears. It comes with a Hose Mount Sheath.

The Blade and Handle Geometry:

Most knife specifications have a basic description of the blade geometry, but in this section I will be taking a more detailed look at geometry and balance.

Key aspects such as the primary bevel angle, grind type, blade depth, blade thickness, length, weight are detailed, along with balance information.

In the case of full convex grinds the approximate centre of the grind is used for the primary bevel angle estimate.

These measurements have been tabulated and are presented in smaller bite size chunks and also in one overall table.
Important – there are critical performance indicators here, in particular the edge angle of the plain edges, serrated edges and cutting hook edges. A larger angle reduces the cutting ability significantly.

The first four knives.
Please note the Benchmade 112S is incorrectly named the 112B in the tables.

The next four.

And the final four.

For a direct comparison this is the entire table. You might need to zoom in or save the image and view it separately to see all the details.

Corrosion tests:

In this Mega Test Review you get an insight into the full process I carry out for all my reviews, but in particular here we have very specific stages. You have already seen some of the studio photography, and technical testing (the parameters), and now we move onto a critical part of the performance testing preparation.

I have chosen to run the corrosion testing before any measured cutting tests, for the specific reason that you will not normally take a dive knife out of the box and immediately ‘need’ to cut ropes and line with it. It is far more likely you will carry it on a few dives before you really need it to cut anything or free yourself from an entanglement. So the idea here is to look at the cutting performance AFTER the corrosion tests, as if the cutting edge is actually damaged by corrosion, it may well fail you when you really need it.

As it turns out, the initial testing site in the Ionian sea, is one of the saltiest seas in the world with a PSU measurement of 38. This is where we digress into the subject of salinity, but I’ll just mention a few key points in the preparation of the corrosion testing.

The chart below (from World Ocean Atlas 2005 data) shows how the salinity of the sea varies across the globe.

The units are shown in PSU which stands for Practical Salinity Unit. The PSU is derived from the ppt (parts per thousand) value of the salts dissolved in a kilogram of water. On average, seawater in the world’s oceans has a salinity of about 3.5% (35 g/L, 35 ppt, or 599 mM). This means that every kilogram (roughly one litre by volume) of seawater has approximately 35 grams (1.2 oz) of dissolved salts (predominantly sodium chloride NaCl). Average density at the surface is 1.025 kg/l. Seawater is denser than both fresh water and pure water (density 1.0 kg/l at 4 °C (39 °F)) because the dissolved salts increase the mass by a larger proportion than the volume.

And breath….

So, due to not receiving all the test candidates before the trip, I needed to replicate the conditions of the initial corrosion tests to keep everything consistent. What I needed was seawater with the same salinity as the starting conditions (also to then be used for the wet cutting tests). This is not as simple as taking tap water and adding salt to it, as the chlorine in the water affects corrosion, and the salts in seawater are not just NaCl. So as a starting point I went to collect some local seawater (from the English channel). This typically has a salinity of 35 PSU, but I was collecting from a beach where rainwater runoff would likely be diluting the salinity.

Fortunately thanks to people keeping fish as pets, there are a lot of easy tools for checking this, and the simplest being a hydrometer to measure specific gravity. The one I have used is for owners of salt-water fish and has a green section indicating the correct salinity range. As you can see here, the hydrometer is showing the salinity is at the lower end of the range (as not much green is showing). Reading off the specific gravity, and crucially the temperature as well, a temperature/specific gravity chart was checked showing that this seawater was measured as 29 g/l or 29 PSU.

This meant that to get to 38PSU I needed to increase the salinity. Fortunately pet shops sell ‘Aquarium Salt’ (which is basically dried seawater and contains all the salts in seawater). All I had to do was add a further 9g/Kg of aquarium salt to bring it to 38g/l. After adding the additional aquarium salt and re-measuring, the salinity was indeed at 38PSU.

Now I had suitably salty seawater, I proceeded to replicate the series of immersion tests carried out over the initial two week test period. This was based on the example of a diver spending around 2 hours in the water each day and then taking their gear out and letting the knife drip dry until the next day (or not quite dry). The knives would have a mixed exposure to air and seawater (which as it dries becomes a much higher salinity). Of course the original tests were carried out in much higher temperatures, so an aquarium heater was used to heat the seawater to match the original temperature.

After the full set of corrosion testing, the knives were soaked in freshwater, then the water was changed for a further soak to bring out the salts. The knives were then dried and inspected.

This post from my Instagram feed shows the results in a ranked order. It must be noted that some results were very close, so the top 5 had virtually nothing between them.

In the final results table, each knife has been given a score out of 25 for its corrosion resistance, so you can find the exact rating in that table, but as a brief description in ranking order:

The Promate Titanium knives were spotless (including the sheaths), the Spyderco had only a single spot due to the black text on the blade, and the Cressi Giant was the only standard stainless steel knife to have no visible corrosion. The Benchmade has some light staining, with the Cressi alligator having only light signs of rust. Then things started to ramp up in corrosion. The Promate stainless knife actually had quite heavy corrosion on the guard but very little on the blade. The Whitby knives all had blade and edge rusting. Worst of all was the Promate line cutter, but this used only standard non-stainless utility blades, so no surprise there. These utility blades can of course be easily and cheaply changed.

A look at serrations and edge geometry:

There are a few aspects which are important to understand which relate to the design of the serrations and the edge geometry, and which affect cutting performance drastically. Though this is a slight digression to talk about the subject, it will help to explain the cutting test results.

You might have skipped over the ‘The Blade and Handle Geometry’ section, but it is worth noting the details in that table. The edge angle used will give a mixture of ‘sharpness’ and ‘durability’, and the smaller the angle the sharper but less durable it is. In the case of the dive knives here, ‘Chisel’ vs ‘Standard’ grinds have a huge effect for the plain and serrated edges, as well as the cutting hooks.

To visualise this, here is diagram of a Single bevel (Chisel grind) and Double bevel (Standard Grind) edge, and both these edges cutting into some material. The Chisel Grind has been sharpened at 22° and as it is a single bevel edge, the total ‘included’ angle is also 22° (22° + 0°). A Standard double bevel edge also sharpened at 22° has an ‘included’ angle of 44° (22° + 22°) and though still sharp, this edge has to part the material much more as it cuts resulting in a much higher cutting force being required to complete the cut.

After looking at the edge angle and its effect on cutting force we also need to consider how the size of serrations can make another huge difference in how well the edge cuts.

Let’s start by looking at two of the blades on test, one with large scallops for the serrations, and one with two sizes of scallop that are much smaller than the first. Between them are a series of different size rope cross-sections.

Coming from the Latin word ‘serra’ meaning saw, for a serrated edge to start cutting it needs to move over the surface of the rope to allow the teeth to start working, but if the serrations are too large, then instead of moving over the surface and sawing into it, the rope can stick in a single serration making the sawing action difficult. Here we can see how the four smallest rope sizes will catch in these large serrations and only once the rope size increases can the serrations teeth start to work on the rope surface.

A blade with smaller serrations is able to ride over the surface of much smaller ropes and allowing the sawing action to work. Only the very smallest rope here will catch in the teeth, with the second smallest the smaller teeth can get to work and the cut will progress.

Smaller serrations are definitely more versatile, but are harder to maintain, so you need to find the balance that works for you. In the cutting tests, the size of serrations does have an impact on the results.

Cutting tests:

The testing in this group review is actually my first direct cutting comparison between steel and titanium blades. I had thought there would be a big difference between these blade materials, but in the experimental cutting tests, the Titanium Vs Steel aspect was not directly evident.

If more extended testing had been carried out, where edge durability starts to come into play, then steel would begin to take the lead, but starting with the factory edge and dealing with a reasonable amount of cutting, edge retention was not a factor.

Being a Dive Knife group test, all cutting tests were carried out in seawater with pre-soaked materials. The list of materials to be cut was chosen after consulting active divers to cover the most common cutting scenarios.
To represent discarded and lost fishing hazards the cutting test includes 15lb and 50lb Monofilament plus 15lb and 115lb Dyneema braid (for fishing lines) as well as 2mm Nylon Braid (netting).
3-4mm Nylon Braid represents cave line, 50mm (2″) webbing as if you were having to cut away a BCD, and cable-ties for cutting away items attached to your gear that might be snagged. Lastly a medium 8-10mm rope as this is a very common size.

With the vast majority of my cutting experienced being with dry cutting tasks, the effect of wet cutting on the different materials was actually shocking. Materials that cut so easily when dry became difficult with the lubricating effect of the water. For some fibrous materials there seems to be a strengthening effect as well (which is difficult to explain scientifically), though this might simply be due to the lubrication making them more abrasion resistant. When wet, the materials are more difficult to grip and in the water the entanglement will often be free floating so needs to be gripped to be cut. Altogether this adds up to a challenging cutting experience and one which shows any weaknesses of the tool being used.

Another Instagram feed image which shows some of the cut materials with the knives.

The totals for each knife’s cutting performance are shown in the final full and summary results tables, but here, just the cutting performance of each knife with each material is shown. The score is a 5 for a very easy and clean cut, down to a 0 for a failure to cut the material. A few of the knives were clear leaders in the cutting tests. Remember, this is also with blade edges that have been through the corrosion tests. The Cressi Alligator has two sets of results to allow the knife blade and shears to be directly compared. The shears were top performers in the cutting test, but were also matched by the Benchmade H2O.

What are they like to use?

A much more subjective section as it is difficult to quantitatively score how each knife is to use. We have considerations such as the leg straps, opening and closing a folder, unsheathing and re-sheathing the fixed blades, size and weight, grip and ergonomics. All of these factors needed to be considered with bare hands and diving gloves, and then translated into an ergonomics score.

There is far too much to cover in this group review, so you will need to refer to the individual reviews referenced at the beginning of this article.

When comparing leg straps, the choice of quick release or buckle fastening will come down to a matter of personal preference. I found that as you need to the fix the strap length for the quick release type, that sometimes the fit was not so good (perhaps if changing leg or even just depending on the temperature), so the standard buckle fitting worked better (despite being slower to fit and take off) as the fit was adjusted for each and every dive.

For the fixed blades, retention methods varied with rubber straps, clips and sprung plates all be used. More information on this will be seen in the individual reviews. On dry land all the knives are easy to unsheathe, but once strapped to you and you are free-floating in water, this changes significantly and shows the strengths and weaknesses of each design. Critically can you access the knife with either hand as your handed hand might be the one that is entangled.

An important consideration is the ease of re-sheathing the knife. This is where you will want to decide if you really need that sharp point or if a blunt tip knife is better.

Once in the hand, how good is the grip.

If choosing a folder, how easy is it to open, especially with gloves. Is it a two handed operation?

A lot of factors and only a score out of 25 to work with. These scores are included in the overall results table.

Overall results:

With so much information to present, unfortunately the only way is with a couple of results tables. There are two tables included here, one is the full results table with detailed cutting test results. This is packed with information and you will need to view the image separately (click on it) to expand it and read all the detailed results.

Please note the Benchmade 112S is incorrectly named the 112B in the tables.

Taking out the detailed cutting test results makes for a more manageable results table, and here the scores have been put into ranking order with the top scores at the top of the table.

Review Summary

Normally I include a Pros/Cons table in the summary, but in this case it is not appropriate (this will be included in the individual reviews). Instead I wanted to mention how to look at these results. You will all have specific needs, you may want a large or small knife, you may absolutely want a knife needing no maintenance (apart from sharpening), you may have a strict budget, or dive in conditions where you often lose knives, so despite what looks like a clear winner in this test you might chose another option.

All the tests in this Mega Review have been carried out with the knives treated as equals, using the same conditions and testing criteria throughout. You may not be surprised to see that the two top scores are from the two most expensive knives, (you really do get what you pay for) which also happen to be from specialist knife manufacturers. Also scoring well are the Titanium blades, even up against steel blades.

I’m purposefully avoiding making absolute conclusions here as the experimental results speak for themselves. The individual reviews will be completed and published as soon as possible and the links will be included at the beginning of this article.

This information should allow you to form your own opinions about what you might look for in a dive knife.

Though I didn’t want to pick one out of these as a winner, there is the question “Do I have a favourite?” – Yes I do. Quite simply for the complete lack of care required in maintaining it, the light weight, the sheath retention and overall package, for me it is the Promate Titanium KF593 Scuba knife. Others come in very close seconds, and are also excellent choices, but if I had to pick one, and have in fact been doing that since the initial testing, it is the Titanium KF593. I also have to give a mention to the Benchmade 112S H2O as if I knew I was going to be doing a lot of cutting, then this knife would overtake the Titanium blade for quality of cut and edge retention. If you follow the philosophy that “one is none, two is one” then, like me, you might carry both of these.

It’s been fun…….

Discussing the Review:

Please feel free to add comments to the review, but the ideal place to freely discuss these reviews is on a forum. If you started reading the shorter forum version of the review, but followed the link this full exclusive review, please return to that forum to discuss the review there.
If you read the review entirely on Tactical Reviews, please consider one of the following to join in any discussion.

EdgeMatters – Sponsored Reviews (UK based Forum for Knife Makers and Collectors)

BladeForums – Knife Reviews (US based Forum for Knife Discussion)

CandlePowerForums – Knife Reviews Section (Largest and Friendliest Flashlight Community Forum)