Question Truefins
- Thread starter scubadada
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Floatingbrick
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I would be happy to try these out. I wear a size 12 shoe and have no problem sending a frog kick video.
I have a few brief questions about fitting and application, let's discuss in dm. Size 12 should work with 3mm bootie, but foot shape also effects shape. Some men's size 13 foot shapes may not fit with a thin bootie.
Also, a general note,,, for those participating in this effort, and if you do in fact provide some video, we do not have to associate a given video with a divers identity. I know if someone took a video of me frog kicking, I would not want anyone to see and criticize how I frog kick. I'm already know I'm not a good frog kicker.
This test of these six fins will not be the last time we do this, and the next test may be for a size medium for flutter kicking during less demanding conditions. As we progress with the spine development and start to understand the real world service life of the spines, we'll then move on to XL size (men's size up to 15), using dry suit boots and pushing doubles. All fin sizes will use the same spines.
By the way, regarding use of these fins with a dry suit we just received the below comment from a user that purchased the fins a month ago.
This is the direct quote. I edited out the location. I haven't asked him if he is a member here, but if so perhaps he could post more about his experience on this forum-
<So far I really like the fins. They felt different when I switched but 20 dives later I don’t even notice now. I’m keeping up with my pals with less effort. I’ve noticed that my air consumption has decreased a bit since using these fins. They seem to work just fine when I’m in my dry suit pushing all that weight to (edited out) with 10 pounds>
Sorry in advance for the long post, but there are a few additional things to say that, if nothing else, users of Truefin that may be lurking here may be interested in. When I am involved in product development I always try to be as open as possible, and often I find that approach to be constructive.
Anyway, the above diver comment was the first time we have received an email from a diver that indicated he had less air consumption. We suspected that had to be the case based upon machine efficiency tests where we measured thrust during flutter kicking and correlated it with power delivered through a torque sensor, but it is good to hear that a diver noticed 'a bit' less air consumption. We are going to work with this diver, if he will agree, while we expermient with different spine materials because it sounds like his application is perfect for stressing the spines. Because the spines have a lifetime guarantee, the ongoing objective is to use materials and injection process parameters to result in the lightest spine with the greatest durability and strength while being at the least cost. That is an objective that is never fully satisfied, if for no other reason than you always want something at the lowest cost.
We are really pushing the limits of current technology getting these spines right, and as I say it will always be an ongoing development process. We have a good team on this, but I will say we are also depending on research and development from resin manufactures. For example, as we explore different materials, a material we will also be looking into if necessary to meet our criteria is Hybrid Long Carbon+Glass Fiber Reinforced Composites by Complēt Hybrid – Long Carbon + Glass Fiber Reinforced Thermoplastic Composites It may not be necessary to switch to something like that, but if we do we would first try short hybrid carbon/glass, while staying with nylon. The spine material we are currently using is 30% glass filled nylon, and the verdict is still out with this material.
A further comment... We have been selling Truefin for around a year and a half, and although we have had ok sales while trying to make divers aware of this product, we had three instances where vertebrae cracked at different part sections. When that happens you don't lose much efficiency because you have other spines working. In fact, you could break all the spines and the fin will just perform as a somewhat flexible spineless fin. Those spines were all replaced for free of course. Anyway, a first instance occurred where it appears some type of accident happened, and the crack was not due to fatigue failure. That failure we have to just set aside because we have no explanation for it. A second situation occurred where a diver was mixing and matching vertebra, blue plugged into yellow, and green plugged into blue, or whatever... That was my fault, because on the web site I indicated that users could do that if they wanted to do some further customization of the spines. That diver had about 100 dives on the fins when a break occurred. I have since removed any comments about mixing and matching vertebra. What I didn't anticipate to be a problem was that when you mix and match, you are creating an unacceptable discontinuous curvature of the assembled spine, and when the spine is stressed, unacceptable 'kinks' in the spine curvature occur thus creating stress concentrations that we didn't analyze with FEA. Last word I had on his use of the fins is that he was using Yellow spines and had 100 dives on them with no issue.
You can see a video of him with such a combination in this video:
A third instance occurred with the diver quoted above, and we are waiting for the part to be returned so we can analyze it. Our initial suspicion is that the nylon resin pellets were not sufficiently dried, and microscopic bubbles or voided areas may have been trapped within the molded part. This may be due to internal steam while the part was being molded, although could also be due to other process variables such as low injection pressure or hold time, low temp or back pressure, or speed, etc. When bubbles are present they act as a stress concentration areas and lead to reduction of tensile, shear, bending strength, and even fracture toughness. I better stop. I really don't want to use exotic materials for the spines because I want the fin to retail below the price of premium spineless scuba fins, while providing a lifetime guarantee to the original purchaser, but as I said earlier, we are dealing with the limits of technology here and learning how to do this right.
STLMEG
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STLMEG
Registered
Ok, it looks like two more sets are committed to-
Once the shipping addresses are provided through DM they will be shipped within 3 days. Due to low inventory of packaged Yellow spines, these two sets will be shipped with White substrate and with Yellow spines installed, and with the Blue and Green spines packaged separately in the shipping box.
Thank you for participating.
Two of the six sets remain available.
Floatingbrick
STLMEGOnce the shipping addresses are provided through DM they will be shipped within 3 days. Due to low inventory of packaged Yellow spines, these two sets will be shipped with White substrate and with Yellow spines installed, and with the Blue and Green spines packaged separately in the shipping box.
Thank you for participating.
Two of the six sets remain available.
STLMEG
Registered
astr0b0y
Contributor
Tried out my Truefins for two dives yesterday and found them to be very comfortable and great performers for frog kicking and reverse kicking. Using yellow inserts (greatest deflection) as i have an ankle injury so wanted to reduce stress on it. I’m coming from Scubapro Seawings which, for me, have excelled in use for gentle to mild flutter kicking, seemingly little effort for great response, but pretty messy frog kick and reverse kick.
I replaced the supplied medium size spring straps with large size (about 4cm longer) as the mediums would unbuckle as they were stretched too far. Wearing Scubabpro 3xl 5mm boots which is supposed to be US12 - I could go a size down for boots, 3xl is pretty loose on me. Truefins size guide seems pretty spot on. I’d recommend buying them without straps and fitting straps that best fit your feet.
So at first blush, these Truefins feel really nice and well made and work very well. The dives were in 12C water and I’m wearing a 5mm wetty. Pretty cold on the second dive so felt my SAC rate was probably going to be very poor because of the cold. Log shows it was the same as warmer dives. Correlation only of course, but maybe more efficient finning translates to less air consumption. That would be nice.
No video yet, buddies didn’t have a cam but working on that.
I replaced the supplied medium size spring straps with large size (about 4cm longer) as the mediums would unbuckle as they were stretched too far. Wearing Scubabpro 3xl 5mm boots which is supposed to be US12 - I could go a size down for boots, 3xl is pretty loose on me. Truefins size guide seems pretty spot on. I’d recommend buying them without straps and fitting straps that best fit your feet.
So at first blush, these Truefins feel really nice and well made and work very well. The dives were in 12C water and I’m wearing a 5mm wetty. Pretty cold on the second dive so felt my SAC rate was probably going to be very poor because of the cold. Log shows it was the same as warmer dives. Correlation only of course, but maybe more efficient finning translates to less air consumption. That would be nice.
No video yet, buddies didn’t have a cam but working on that.
I'm the right shoe size (US 11 men's) and can take a video.
No rush at all for the frog kicking video with Green spines,,,, let your injury heal.
Thanks for the note about the provided stainless steel spring straps. It sounds like you noticed that we also list Truefin large available without heel straps. By the way, I'm not aware of any other company selling fins without heel straps but if anyone reading this can think of an example where some other company sells fins without heel straps I would be interested to know.
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