Questions about Speardiver carbon fins

I will answer questions about Speardiver carbon fins in this thread. I'll try to answer promptly and hope others who use the fins will provide information based on their experience, as some aspects of the fin's performance have to do with personal preference. Speardiver fins are available from spearfishing.store. You can also get information contacting through the store website.

I've installed Speardiver blades in just about every foot pocket available. They install well in all of them, and small modifications to the back edge of the blade can be made if necessary for perfect fit. OMER Stingray foot pockets are a good example of how a small modification that needs to be done to the blades for optimal fit.

I can't pinpoint a favorite. Fin selection starts with choosing a foot pocket that fits you well and has the right characteristics. General information on good foot pocket characteristics can be found here http://spearfishing.world/fins…cket-characteristics.html. Specific reviews of different foot pockets here http://spearfishing.world/fins…-footpockets-reviews.html

Speardiver foot pockets are the natural choice, OMER Stingray and Cressi Gara Modular are also good. The foot pockets available from spearfishing.store are only those we found to be comfortable, durable and good performers. I'll install Speardiver blades in any foot pockets that you provide. But with some foot pockets, like Pathos we do not offer the 2 year warranty on the blades.

I can't give you a specific date but shortly after I started offering the Pathos f/p about 2 years ago. I would tell anyone who bought Speardiver blades with Pathos foot pockets, and I mentioned it in the forum a couple of times. The reason for it is that I don't feel Pathos foot pocket tendons offer enough support to the blade. This has been confirmed by an unacceptable number of blade failures, all with Pathos foot pockets. This has been the case with 1st generation Pathos foot pockets of which I had the pleasure to see only one pair, they had very soft tendons. I went with 2nd generation which had very stiff tendons, but kept the no warranty condition because of warnings I've received about the foot pockets (although they were probably based on the 1st generation f/p). I had no breakages from the 2nd generation f/p but at the time 3rd generation f/p came about blades started failing again, so the no warranty continued.

3rd generation have tendon stiffness somewhere between 1st and 2nd. At first I was really happy with them because 2nd generation were really too stiff. But then realized 3rd generation have little backbone, which can be felt when swimming against current or fighting a big fish. Some people (on this forum too) believe that a carbon blade should be able to handle the stress of being combined with very soft tendons, which is almost equivalent to the foot pocket having no tendons. I've been adamant against this idea. If you think carbon blades should handle it and be warrantied you can put other brand blades in Pathos foot pockets. There's a reason Pathos went from 1st to 2nd then to 3rd generation. I think going back to 2nd generation would be a good move. Although I've come to believe there's something about the design and tendons being so thin, that when they're stiff just doesn't allow for a gradual enough dissipation of stress away from the foot pocket toe for the fin to be comfortable, or if it's soft enough to be comfortable to support the blade adequately. It's ironic because I'm probably responsible for introducing them in the US, and to some degree affecting Pathos to make generation 3.

That said my fins are still Pathos f/p, albeit little used lately, and there are other guys here who are using Pathos with Speardiver blades and the blades have already outlasted the foot pockets two years later and been switched over to new foot pockets. I believe they're all 2nd generation though.

Quote from Garibaldistoner

Is it safe to drill holes for mounting the screws, or will drilling a hole cause it to fracture?

Retention of blades in foot pockets that use the rail system mostly comes from the foot pocket tendons gripping the rails that are glued to the blade (if the rails are good). The screws only serve to keep the blade from slowly working it's way forward out of the foot pocket.

Carbon blades from different manufacturers vary in quality, some are simply prone to failure. Screw holes on most foot pockets are located near the blade toe angle which is a high stress area. Additionally some foot pocket kits come with ridiculously large diameter screws requiring large holes. Consequently you have a recipe for a blade breaking along the screw hole line, so it is a valid concern.

Case in point these C4 (not Speardiver) blades that a customer brought to my shop. Notice the C4 blade is glued in a Pathos foot pocket therefore installed without screws. But the screw holes are there from a previous installation. The C4 blade broke along the screw hole line being used with Pathos foot pockets. I've seen C4 blades break in that exact spot being used with other foot pockets too.

But using screws does not automatically mean a broken carbon blade. First of course choose reputable carbon blades like Speardiver. Foot pocket mounting kits like Speardiver, OMER Stingray, Cressi Gara Modular and Beuchat use smaller diameter screws. The pressure on the blade is dissipated by the screw support plate which has variable thickness, allowing itself to be positioned to make the screw heads lay flat relative to the carbon blade.

Additionally at Speardiver we never "drill" holes in carbon blades. Instead we use a proprietary method to make the screw holes, it disturbs the integrity of the carbon material significantly less than drilling. Provided these factors are addressed, it's been my experience that done properly a screw installation is safe and durable. Which is why Speardiver offers a two year warranty.

With older style foot pockets that don't have a recess for the top screw retention plate, and/or don't have a bottom screw support plate, I prefer a zip tie to secure the carbon blade instead of screws. I can get away with two tiny slots, just enough for the zip tie to pass through the blade.

When installed properly all foot pockets hold blades well. This question shouldn't influence your foot pocket choice. Making holes or slots in blades would only affect the warranty if the blade breaks along the holes line.

Gluing blades in a foot pocket doesn't void Speardiver blades warranty.

Your warranty for foot pockets would be with the manufacturer of the foot pockets.

For gluing water channeling/footpocket rails:

Do not use 5200.

Use any Cyanoacrylate/Instant glue (thin viscosity, NO GEL)

Use a box cutter to clean off rail residue. Old filet knife :crazy: of course you're dreading the moment of having to do it again. Like anything else use the right tool for the right job and it becomes easier.

Avoid pushing off the bottom with the fins (I use the gun/spear point), and hitting the bottom with the fins in general, the rails will last through a couple of years of good use. There are no "better" rails, and no better way to glue on rails. Every carbon fiber fin available is using this system and it's a proven system. You can try using foot pocket rails in place of the water channeling rails, just to protect the blade edges, these will last longer under heavy use, but will negatively affect the stability of the fin as it's pushed through the water.

Quote from hank

Thanks Dan. Out of curiosity, why doesn't 5200 work? It can't take all the movement?

It will not work because unlike Cyanoacrylate glue, 5200 is essentially a sealer and doesn't "bond". This is an area where you can't take a chance because the blade popping out of the foot pocket can make for a dangerous situation. If for some strange reason you had nothing to use but 5200 (crazy glue is cheaper and available everywhere) the time and effort involved in positioning, repositioning, clamping and waiting for the 5200 to dry and take effect are not reasonable. Instant glue is well.. instant, your fins will be ready to go immediately.

At 78cm long the Speardiver C90 carbon blades (90 refers to the total fin length/including the foot pocket) are the accepted standard length for freediving long fins. The C100 blades are 10cm longer at 88cm, 100cm total fin length.

While 10cm doesn't seem like a big difference, there is a noticeable difference in feel and function. The extra length allows the fin to create what has been described as a Sine wave or a repetitive oscillation, which translates into more propulsion. Of course there's a limit to how long you'd want a fin to be, regardless of how much additional propulsion this oscillation effect creates. 88cm has been found to be the minimum length necessary to produce the oscillation effect, which still allows the fin to be maneuverable for movements other than streamlined kicking.

With the longer fins you will feel an increase in propulsion, but they will be less maneuverable. If your diving/kicking style is smooth and consistent, with the majority of your movements planned in advance, not requiring abrupt change in direction and sudden bursts of speed, you may prefer the longer fins. If you're often twisting and turning on the bottom, like when lobstering, you'll find they're cumbersome to swing around and tend to bump into stuff (that's why I went with the rounded front edge for the C100).

One aspect of the longer fins that's a little hard to explain but I'll try.. It's more difficult to dominate them, rather you have to work with them. For example if you need a sudden burst of speed you will not be able to make them do that instantly. If you wanted to maintain a fast kick, it's harder to do. The fins dictate the pace.

I prefer to use the standard length long fins (C90).

These observations apply to all fins of similar length fiberglass and carbon, not just Speardiver C90 blades.