Pathos Fireblade and Salvimar 4One reviews

    These two footpockets are currently high in demand and considered by many to be two of the best currently on the market. Having now used both of them I felt I'd share my experience...the reviews are based on my own experience as a Freedive Instructor/judge (Full time:) ) where I use equipment on a daily basis for everything from my own deep dives, instructing, freedive photography and videography and working as a safety diver in our competitions. Hope it helps give some informative information to assist other divers in deciding...:)


    Salvimar 4One Footpocket Review
    By Jacques de Vos | Published Jan 17/2012


    This review is aimed at competitive and recreational Freedivers (deep diving).
    Some time ago I did some research to find the best footpockets for a pair of newly acquired carbon blades and although there are quite a few options available on the market, my search was finally narrowed down to two brands. Presently considered amongst many to be the best on the market, the two options were the Salvimar 4One footpocket and the Pathos Fireblade footpocket – which I discussed in a previous review.



    As a full time Freedive Instructor and Freedive Photographer and Videographer I needed something which would be good as an all round footpocket even when doing deeper dives myself. I managed to get some very honest answers from a well known online dive store (from whom I eventually ordered the 4One’s) as they stocked both pairs at roughly the same price. Here is the original email concerning the Salvi 4One’s (the sender is Bulgarian, hence the poor English):

    “Hey, Jacques…

    The Salvi is a heavier but much more comfortable footpocket. It’s perfect for student dives at 30m as well as depths and deeper. It’s as soft as the fireblade if not softer. The angle is more or less the same and the pocket could be fitted to any blade.

    Note that the groove on the ribs is wider (like on OMER). When mounting you glue a separate thin rib on the blade. After that you fit the Salvi with just few drops of glue. When you change the blade you can remove the footpocket without destroying it, which makes it reusable! And this is very important I believe!

    my recommendation as of this moment is – Salvi, because:
    - it’s good for dives to 30m.
    - it’s more comfortable
    - it’s reusable!

    Regards”


    As my blades were already drilled and I never used to be a fan of gluing blades into footpockets (that has changed), I settled on the slightly heavier Salvimar footpocket…

    The Review:


    I would never have guessed it but mounting the blades turned out to be a nightmare…the rails on my blades were not big enough (although they were the standard rubber profile attached to most blades) to fill the MASSIVE rail cavity in the ribs of the footpocket. The guys at the Dive store were not kidding, the groove was more like a canyon! Definitely much wider than the OMER footpockets and the ‘entry’ to the cavity measures 5mm with the actual rail section inside being almost double.


    Note the massive gap for the rails. The entry point for the footpocket is so wide that it leads to potential ‘play’ whilst diving…



    Having mounted a few blades before using Sikaflex (if memory serves me right 291 – marine grade ) as it is easy to disassemble if needed, I opted to ‘glue’ the rails into the footpocket to make it fit snugly. The part of the footpocket where the ‘tongue’ of the blade enters the footpocket also needed A LOT of padding as the groove was as wide as the rib groove and the footpocket would have way to much ‘play’ while diving which would surely result in a break.



    Quite a large amount of play is visible at the point where the tongue of a blade (blue) is inserted into the footpocket    .



    Sikaflex is nasty, nasty stuff…no matter how cleanly you try to work you usually end up with hands so black it looks like you strangled a roughneck on an oil rig…only difference is you can wash off oil, Sikaflex on the other hand can take days to remove (quick hint: forget soap…just wait for it to dry and spend your time picking it off). The curing time is also something ridiculous so I usually leave the glued and very well taped blades to stand for at least 3 days before even considering using them.



    Sikaflex 291…messy



    A very important note: If your blades are not secured in the footpocket, meaning the tongue of the blade which slides into the footpocket has too much room for movement (or ‘play’) especially at the point where they flex, the blade could potentially snap due to the stress caused by lack of support beyond the point of attachment.

    SO

    Finally I get to start using the blades in their newly fitted Salvimar 4One footpockets and here are the results:

    At first I was very impressed with how comfortable they felt especially considering they were not the lightest footpockets I’ve ever worn. I tend to dive without socks and was very happy at how comfortably the footpockets fit. The only thing which initially caused me some discomfort was the two little ‘horns’ on the back of the pocket. I never got completely used to them but it might be due to the shape of my feet as I’m sure many other divers don’t feel them at all.

    Pros:

    • Quite light (although nowhere near as light as the Pathos Fireblade)



    • Comfortable fit and quite soft



    • Lots of reinforcement across the bridge of the foot to optimise power transfer into the blades



    • VERY well finished (they look beautiful straight out the box with no apparent (keyword!) defects or blemishes



    • Nice angle (as stated in the email) which is ideal for deeper dives – nice angle during freefall section of a deep dive.



    Cons:

    • The rib grooves are far too wide…actually ridiculously wide.



    • ‘Horns’ on the heel seems to serve to practical function and causes discomfort when diving



    • Worked well when not wearing socks (apart from the fact mentioned beforehand)



    • The Ribs are too thick – This results in a reduction of the intended blade flex characteristics and performance as the thick ribs acts like struts and reduces the ability of the blade to flex the way it they were intended to by the manufacturer. With soft blades they essentially cause them to feel stiffer…(see the review for the Pathos footpockets for more information on this)


    The
    VERY thick ribs of the Salvimar 4One compared to Pathos Fireblade. The wide ribs reduces performance of the blade dramatically and is enough reason for me not to invest in another pair of 4One’s.



    And then…

    After a month of use they started to become undone…literally!
    Quite soon after I started using them I started feeling something irritating my foot and sticking my finger inside, all I could feel was a bump and some sort of ‘grassy substance’.



    The threadlike substance which at first appeared to be a small defect until eventually it got worse…



    Soon I started noticing something resembling a thread starting to appear on the outside of the footpocket (where no friction occurs) and with every dive it became more and more visible. I realised that the thread I was seeing on the outside was somehow connected to what it was I was feeling inside the footpocket.

    For some or other reason the rubber compound of these footpockets contain some sort of threadlike substance – perhaps to increase strength?…who knows, but there seems to be no logical planning into how it is distributed. My first impression was that it was a piece of string that fell into the rubber mould (its that bad!) leading to a defect footpocket, until we started inspecting a new pair and found the same thing right underneath the surface of the rubber. The only problem is that there seems to be no logical assembly to these threads and this was later confirmed by comparing other pairs of brand new Salvi 4One’s, where when viewed closely a line shaped protrusion is clearly visible in certain areas of the footpocket (in particular around the bridge of the foot) and as mentioned before they never seem to be in the same place.



    The original image I sent to the dealer to bring their attention to the problem…



    I was very disappointed in the short time it took for the footpockets to start disintegrating to the point where it was too uncomfortable to dive without socks and it was clear that the largest of the threads would eventually lead to a tear right through the side of the footpocket. The first thing I did was to contact the seller for an exchange which ultimately led to my first pair of Pathos Fireblade Footpockets which was brought to me from Greece.

    Searching the internet I have found very few reviews on the 4One’s as most people tend to discuss them quite vaguely (talking about comfort and weight only). I hope this review will help future buyers to inspect their 4One’s closely before paying the ridiculously high prices they sell for or if you have already invested in a pair, to at least to check them closely for any defects. The more people bring this major defect to Salvimar’s attention the more likely they are to improve the quality of their product.

    Final Thought


    I would be very reluctant to recommend Salvimar’s 4One to anyone wanting to use them for deep diving and as my previous review of the Pathos Fibreblade has shown the Pathos footpocket is superior in both performance and quality. Given the fact that they are roughly in the same price range its really not that hard to pick one.



    Pathos Fireblade Review
    By Jacques de Vos | Published Jan 17/2012


    This review is aimed at recreational and competitive Freedivers (deep diving):
    After a disappointing run with my previous footpockets (Salvimar 4One – a review to follow), I decided to go for the other current favourite among spearos and freedivers…the Pathos Fireblade.




    Before purchasing these footpockets I sent an email to a well known online dive store from whom I purchased my Salvi 4One’s, to ask how the Pathos compares to the Salvi footpocket.
    The person helping me is a very accomplished Greek spearo and the response I received was the following:

    “Hi Jacques

    here’s some more info regarding the footpockets.
    The Fireblade is made with an angle. I haven’t measure it but I believe it’s 22 degrees. The footpocket is very soft so it would fit any blade from 15 to 26 and more. It is made with performance in mind and is preferred for dives under 30m of depth because it’s lighter. However the comfort is reduced. It’s usable with 3mm socks without any problem. With 5mm socks it’s getting just a bit uncomfortable but nothing to worry about. When I say uncomfortable I mean it compared to other brands. If you get OMER, the Fireblade is much more comfortable due to its softness… Compared to Salvimar though it’s just a bit less comfortable since the Salvi has a better pocket.
    Here’s one thing that is very important – the groove on the footpocket is thinner to fit the blade directly. Therefore you have to glue the pocket directly. This means you can use the Fireblade only once! If you can’t change the blade without destroying the pocket!

    Regards”

    I decided that I would give it a shot and had Linda Paganelli bring me a pair from Greece…

    I’m writing this review after six months of full time use of the Pathos footpockets on carbon blades, using them for everything from daily instructing, my own deep dives, freedive photography and videography to safety dives in competitions. Therefore I can truly say I’ve put them through their paces and the review is based on multiple hundreds of dives under different conditions.



    1. They are SERIOUSLY Light


    This is probably one of the first things which come up in any conversation when discussing these footpockets and the reason it does is because it is so true it’s awesome. The weight compared to other footpockets is so huge in difference that the feather light weight of the Pathos on my Carbon blades makes it feel like I’m holding a sheet of paper (ok, not quite…but it’s really light). A single 42-44 size Pathos Fireblade footpocket weighs an incredible 390 grams! Does this matter…yes! Having a decent blade setup combined with feather light footpockets on deep dives makes a world of difference…like having the thrust of fins while feeling like there is nothing on your feet!

    2. They ARE comfortable


    In the email sent to me (above) it was said that these footpockets would be less comfortable than the Salvimar 4One’s…I disagree completely!

    I do all of my diving in Dahab without socks and this is how I’ve been using my Pathos Fireblades. They are super comfortable and also soft but not so soft as to lose any power. An important point to make is that Salvimar loves to advertise the ‘power band’ over the bridge of the foot on their 4One’s. Incidentally the Pathos Fireblades have exactly the same feature, it’s just not made as obvious. The Salvimar 4One’s have some reinforcement in this area and it is ‘visible’ to the wearer by the ribbed shape banding on the surface of the footpocket (purely aesthetic and great to bring this feature to your attention). Pathos has a similar band of reinforcement over the same area but it is not visible when looking at the footpockets in store (smooth, clean surface), but it is however visible when viewing them underwater. As the rubber gets wet (and discolours) you can clearly see a different colour banding across the bridge of the foot…more importantly you can feel it as a thicker less flexible part over the bridge, even when using your fingers.

    3. The most important part…Ribs


    When blade manufacturers produces a blade they do so with very particular specifications in the sense that a blade is designed to flex a certain way, bend at a certain point and be able to have a particular ‘return’ (the speed at which the blade snaps to its neutral position after being flexed).

    So many people spend hundreds of dollars/Euros on fancy blades and then deprive them of all their awesome features by sticking them into the wrong footpockets. The biggest problem:

    The width of the ribs…(the two extensions which mount to the sides of the blade)

    Its quite easy to understand, have a look at the comparison between the width of the Pathos Fireblade ribs and the Salvimar 4One ribs:




    Due to the MUCH thicker ribs on most footpockets (like the Salvimar 4Ones), the blade is unable to flex at the point where they fit into the footpocket with the efficiency they were intended to. This has the biggest effect on softer to medium stiffness blades as you can have the softest blades in the world, but if you stick them in a footpocket with ribs the width of your wrist they just won’t perform the way they should. You end up with the majority of the blade flex occurring at the point where the footpocket ribs end.



    Other footpockets have ribs which are too stiff resulting in poor blade performance    …



    The Pathos ribs are so narrow (hence the statement in the email which almost sounded like it was a matter of concern) that they allow the blade to function at is optimum specs. I have always been aware of this fact but recently it was proven quite efficiently when someone using a pair of carbon blades similar to mine (I designed the blades so the specs were identical) had them mounted in a pair of OMER footpockets. Trying his fins and comparing it to mine was shocking…even though its exactly the same blades it felt like they were 50% stiffer (due to the much thicker ribs) and diving felt noticeably harder due to a lack of thrust and an increase in weight.



    Note the thin ribs compared to the original rubber profile of the blade



    Based on this alone I’d buy Pathos Footpockets again and again…

    4. To screw or to glue?


    This point comes up quite a lot when selecting footpockets, sometimes even becoming the deciding factor. Personally I hate screws…they look crap and most importantly they weaken the blades (a point proven in my previous post).

    The rib grooves on the Pathos Fireblade footpockets are so narrow that it is necessary to remove any blade trimming (like rubber profiles) and gluing the footpocket straight to the blade. The upside to this is what was mentioned before, there is less rubber ‘strutting’ to interfere with the performance of the blade but the downside is that once they are glued in, it’s permanent. I have had to remove a pair of Pathos footpockets from Fibreglass fins before and it involves cutting the footpocket to pieces (the blade of course survives), so in that regard the email above was correct. In my opinion it’s worth it…the Pathos Fireblade footpockets are constructed so well that it’s unlikely that they will perish easily so you should get years of (efficient) diving from them. As an instructor I’m in the water every day with mine and there is no sign of wear and tear yet, something my Salvimar 4One’s did not live up to…



    Extremely thin ribs make the Pathos Fireblade very efficient in combination with the right blades



    The Bottom Line:


    I have no complaints about these blades and I’m unlikely to change brands again…despite the permanent nature of the Pathos in terms of mounting, I doubt I will have any reason to replace my current pair, but when I do I will most definitely go for another pair Pathos Fireblades.

    Edited 3 times, last by jdv ().

    Thank you for the reviews Jacques, they are consistent with mine and expand on other various important points.


    Salvimar http://spearfishing.world/fins…e-footpockets-review.html. This is what I did with the Salvimar footpockets I bought to try. It's amazing to me how many companies are using Salvimar footpockets rebranded, in the US Persistent and Hatch customs to name a couple.



    Pathos http://spearfishing.world/fins…kets-review-take-2-a.html. Tendon stiffness is not only dependent on thickness, but also material. Pathos footpockets are currently at generation 3 with good moderate stiffness tendons. Generation 2 had the same thickness tendons but they were too stiff, generation 1 were too soft.

    Thanks Dan!


    I was shocked to learn that others were just re-branding the same junk...its incredible how companies manage to pawn off something of such a low standard at such a high price.


    Will keep posting reviews on all the equipment we use here.. :)

    I was surprised to read the negative review of the DeltaOnes, because my friends and I love them. I wanted to briefly add some counterpoints to JDV's well-written review and hopefully get some feedback.
    One thing I wanted to address off the bat is the comfort of the footpockets. JDV eluded to the fact that comfort is quite variable depending on the individual. I would have to say, in my opinion, the Salvimar is the most comfortable footpocket, even surpassing the widely acclaimed Beuchat pocket. I never had a problem with the "horns," and in fact, they are created by a divot designed to be less abrasive to your Achilles.
    Also on my mind was the stiffness of the ribs. Clearly a fin will not flex as drastically when braced by a thicker rib, but given that fact alone I am hesitant to make the statement that the pockets reduce the performance of the fin. I have had fins (Esclapez, for the record) that bend just beyond the toes (such as you would expect to happen with a soft rail) and in my judgement they were the worst fins I have ever used. I'd like to see some empirical evidence on the rails' effect on fin performance... and then if it shows I'm wrong, I'll gladly admit it.
    The last point you made about the Delta One pockets regarded their weight. They are heavier than all fin pockets I have tried previously, save Spettons. Intuitively, I would imagine a lighter pocket would be preferable. However, I don't think the Delta Ones are egregiously heavy. I'm not even sure they are heavy enough to affect performance. Let me try to elucidate my thought by making an analogy: you want a light toothbrush; at some weight a toothbrush simply gets too heavy to use. But a 1 oz toothbrush is not necessarily superior to a 2 oz toothbrush. Both fall below the threshold of "too heavy." Likewise with footpockets.
    I just wanted to offer those counterpoints, because I really like my Salvimar DeltaOnes. Unfortunately I cannot compare them to the Pathos pockets. However I have used Spettons, Sporasub, OMER Milleniums, Beuchat, Cressi, Esclapez, and Dessault, and for me, the Salvimars come out on top. Which other ones have you used, and how do you rate them?

    Carbonio GFT (the 80 cm version), med stiffness.
    I have used them to dive CW 60m (200 feet) and spearfish down to 155 feet.
    In deference to the reviews started here by jdv, I will post my thoughts on these fins in another thread.

    Edited once, last by fishon ().

    Quote from fishon


    Also on my mind was the stiffness of the ribs. Clearly a fin will not flex as drastically when braced by a thicker rib, but given that fact alone I am hesitant to make the statement that the pockets reduce the performance of the fin. I have had fins (Esclapez, for the record) that bend just beyond the toes (such as you would expect to happen with a soft rail) and in my judgement they were the worst fins I have ever used. I'd like to see some empirical evidence on the rails' effect on fin performance... and then if it shows I'm wrong, I'll gladly admit it.


    A couple things to keep in mind with the fin rails aka tendons. One is that thicker does not always mean stiffer. The other has to do with the nature of a composite fin. The reason that fiberglass and carbon fiber blades are superior to plastic is there ability to store energy and return to their original shape. This is often referred to as the "snappiness" of a fin. Plastic fins dissipate some of the energy that goes into deforming them and also do not return completely to their original shape. This waste of energy is known as dampening and is why plastics and rubber are used as shock absorbers and bushings. To use your example of the esclapez fins. They have a very long tendon that has a lot of material. This tendon negates most, if not all, of the advantage gained from putting a carbon fiber blade in that pocket. If you look at some of the top foot pockets, like the c4 and Pathos pockets, there is little or no tendon. The pathos have a very small and flexible tendon that allows the blade to do all the work. The C4 pockets dont have a tendon at all.


    As for the weight of the footpocket, its not so much that the heavier pockets are "too heavy" and more that the ultra light ones are reaalllllyyyy nice. In your toothbrush analogy you have a very short duration. Try looking at a day of spearfishing as more of an endurance race. There arent any footpockets (to my knowledge) that are so heavy that they cant be kicked by an average diver or that will make you sink. However, if you had to run a marathon would you choose a set of really heavy hiking boots, (which arent too heavy to walk in) or a set of top of the line running shoes? Also in a sport were efficiency is very important, the less energy spent accelerating a foot pocket, the more is put into moving water. It may not seem like a lot but my pursuit 90's in pathos pockets are roughly half the weight of my cressi garas and over the course of a day with a few thousand kicks it adds up.


    The comfort of the pocket is completely a personal choice. I love my garas they are the most comfortable fins I have every owned but after a few dives to adjust to the carbon blades, the Pathos pockets are a close second. Initially I had a little pain because I have a high arch and the pocket is a little flat but my foot has adjusted and the pockets have been broken in a bit. They now fit and feel great.

    Quote from Wishihadgills


    As for the weight of the footpocket, its not so much that the heavier pockets are "too heavy" and more that the ultra light ones are reaalllllyyyy nice. In your toothbrush analogy you have a very short duration. Try looking at a day of spearfishing as more of an endurance race. There arent any footpockets (to my knowledge) that are so heavy that they cant be kicked by an average diver or that will make you sink. However, if you had to run a marathon would you choose a set of really heavy hiking boots, (which arent too heavy to walk in) or a set of top of the line running shoes? Also in a sport were efficiency is very important, the less energy spent accelerating a foot pocket, the more is put into moving water. It may not seem like a lot but my pursuit 90's in pathos pockets are roughly half the weight of my cressi garas and over the course of a day with a few thousand kicks it adds up.


    I will not argue with that. The only counterpoint I would add is, which would you rather run a marathon with: a lighter shoe that does not fit well, or a slightly heavier one that is comfortable. I won't pretend to see an advantage to the added weight though.

    Quote from Wishihadgills

    The reason that fiberglass and carbon fiber blades are superior to plastic is there ability to store energy and return to their original shape. This is often referred to as the "snappiness" of a fin.


    I understand that, but I still would like to see some data before I'm willing to say that the fin pocket is hampering my blade's performance. Each blade is obviously different, but I would say most benefit from some tendon (although I could be wrong, I haven't actually tried every blade). Additionally, I don't think it's all "snap" we're looking for. I think that simplifies it a bit too much. If that were the case, one patch of carbon where the flex happens would be all you needed, the rest could be any material right, provided the carbon could snap it back into place? I read an article (which I might look for later) positing that you actually want to create a sine wave. In fact, if you could manage it, you would want multiple sine waves. Feel free to correct me here, because I'm just a secondary source on that information (information I don't really understand at that). That's more the realm of hydrophysicists or something... I'm just a fisherman.

    fishon, have you separated the blade from the footpocket? If you do you will see that the back edge of the blade is cut to match the "tab" inside the salvimar footpocket. This tab has no practical advantage, and doesn't allow the use of any blade that wasn't specifically designed for the salvimar footpockets. Of course you could say that you wouldn't want to use anything other than the carbonio gft blades. But I don't like the idea of needlessly chopping up the back edge of a carbon blade. If the other points can be debated and attributed to personal preference or lack of experience with other footpockets, this last one can't and it's a decisive point for me.


    In addition at the risk of starting a controversy and maybe stepping on a few toes, I'll say the following. I was interested in salvimar products because of their unique appearance and availability, and examined their products first hand. From footpockets to shafts to spearguns, I find salvimar equipment designed to be eye catching and different, and completely over the top, reminding me of the haute couture concept in fashion; crazy looking shit that no average person would actually wear. Experienced people in the dive gear industry who's opinion I respect share my conclusion. But in the end everything's a personal choice, so I'm sure someone will really dig salvimar equipment for spearfishing. If you're a practical person like me however, take my advice and stay away from it.


    Quote from Dan

    fishon, have you separated the blade from the footpocket? If you do you will see that the back edge of the blade is cut to match the "tab" inside the salvimar footpocket. This tab has no practical advantage, and doesn't allow the use of any blade that wasn't specifically designed for the salvimar footpockets.


    I was unaware of that! Up to now I had used only a Carbonio fin in those pockets, which worked great. However, in two weeks I have another pair of DeltaOnes coming in which I intended to use for a pair of Pierre von Eecke's. Stay tuned.. there should be a new review in the coming weeks.

    Quote from fishon

    I will not argue with that. The only counterpoint I would add is, which would you rather run a marathon with: a lighter shoe that does not fit well, or a slightly heavier one that is comfortable. I won't pretend to see an advantage to the added weight though.



    I would agree that better fitting outweighs an extremely light fin. If the Pathos dont fit then I would suggest a different pocket but if they do then I think lighter is better.


    Quote from fishon

    I understand that, but I still would like to see some data before I'm willing to say that the fin pocket is hampering my blade's performance. Each blade is obviously different, but I would say most benefit from some tendon (although I could be wrong, I haven't actually tried every blade). Additionally, I don't think it's all "snap" we're looking for. I think that simplifies it a bit too much. If that were the case, one patch of carbon where the flex happens would be all you needed, the rest could be any material right, provided the carbon could snap it back into place? I read an article (which I might look for later) positing that you actually want to create a sine wave. In fact, if you could manage it, you would want multiple sine waves. Feel free to correct me here, because I'm just a secondary source on that information (information I don't really understand at that). That's more the realm of hydrophysicists or something... I'm just a fisherman.


    The elasticity of an object is a measure of how well it returns to shape after it has been deformed. If you compare the elasticity of rubber or plastic to that of a composite material you could compare how well each material could store the energy. If you were to have just one piece of carbon and another material than anything with a lower elasticity would "slow" the carbon down and prevent maximum energy storage.


    Without researching the article the sine wave sounds about right as it is the most efficient form of a wave. Becaeuse of how carbon and other composites store energy they would approach a sine wave but if one half of the composite was affected in its flex by rubber and other materials than it couldnt form that wave properly. The longer carbon blades are more efficient because one they move more water but also because less of their total length is effected by the tendons. If you look at c4 pockets they dont have any tendons (they have water channeling rails) but the blade is allowed to store as much energy as possible. The purpose of a footpocket is to transfer as much energy as possible to the blade as easily as possible. Sporasub tried to exaggerate this concept with one of its fins (the one that looks like a shoe) but they made a critical error in blade material. The plastic they chose simply couldnt hold up.


    I’m not sure about the multiple sine waves, ideally if you could get the wave to propagate properly multiple waves would work but it would be extremely hard if not impossible to accomplish. Some of the problems that afflict current footpocket designs are the trade offs manufacturers are forced to make. Ideally you would have a pocket made from a mold of each foot but its obvious why that doesnt work for a production product.


    I would really like to see if someone could come up with a test that could show a measurable difference in footpocket/fin design but it would nearly impossible to set up objectively. Ive also considered trying to make a custom pocket for my own feet and the idea of having a carbon blade that extended through the heel of the foot and instead of mechanical attachment like screws or some kind of lock actually have the blade integrated into the rubber (or other material) of the pocket. It would make an ideal fin but would be very difficult to do and very expensive to try.

    Quote from Wishihadgills

    If you were to have just one piece of carbon and another material than anything with a lower elasticity would "slow" the carbon down and prevent maximum energy storage.

    Also most people are not aware that even the color (camo) patterns some manufacturers are now adding to their carbon blades negatively affect the performance. Less so when it's just paint, more when it's a separate layer. General rule of thumb is stay away from carbon blades that don't display the conventional carbon pattern.

    Quote from Wishihadgills

    Sporasub tried to exaggerate this concept with one of its fins (the one that looks like a shoe) but they made a critical error in blade material. The plastic they chose simply couldnt hold up.

    Actually the plastic blades are the only ones that could hold up for any length of time. or I should say when they break they won't break the bank. I'm going to repost from another thread:


    The function of the tendons is to give the carbon blade support, and evenly distribute the stress of bending away from the footpocket. When the tendons are too soft and provide no support, the blade will bend most at one specific spot an inch or two past the foopocket, then there's a bigger possibility of it breaking in that spot. That's why this design from Sporasub has never been used for anything but plastic blades.



    The C4 footpockets may seem to be a good idea because they appear to lack tendons completely. On close examination that huge flap in front of the C4 footpockets weighs just as much as conventional tendons and provides the same support.


    http://www.youtube.com/watch?v=tW_GlTP_VzI


    Xan, your idea about a full length blade sounds nice in theory, but the reality is that without tendons it will have the same flaw as the Sporasub running shoe fin, there will be too much stress at one point without tendons and the blade will break. I suspect it would also put a lot more stress on the ankles. The job of the footpocket and tendons is to dissipate just the right amount of energy, to not overwork the blade and ankles.

    It may weigh a lot but the flap does a good job of distributing the forces of the kick without hampering the ability of the carbon to return to shape. It also allows the fin to gain width quickly without excessive length.


    As for the sporasub fins I have to disagree with the choice of material. If they had layered the carbon sufficiently so that it could sustain the force and distribute it through the blade (think like the leaf spring on a car) then they would have a very efficient, albeit extremely expensive, fin. Unfortunately for that to work properly the blade would have to be full foot and have a different style of attachment. The plastic simply cant hold up to that level of stress over a lot of cycles.

    It would be really stiff at that point but could taper off very quickly. I dont know if your familiar with the new jigging rods for H&L fishing, the butt of the rod is really stout but the tip remains really flexible. It would take a little modification to the design and the point where peak forces are would have to be moved back toward the ball of the foot instead of out past the toes. It would be a fine balance and could be difficult to offer varying stiffnesses but it should be possible. Expensive but possible.

    Thanks for the informed and considerate replies. What is the angle of the footpockets you use? Do they match the angle of your blades? What do you believe to be the optimal angle?

    I don't know if your question is directed to me, but IMO a 20 degrees toe angle is ideal. By the time you get to 30 degrees like the DiveR blades, you will feel your hamstrings get tired because the fins are now working more on the up kick. It's the down kick where we naturally generate power/propulsion, the up kick is a waste of energy..

    Quote from Wishihadgills

    It would be a fine balance and could be difficult to offer varying stiffnesses but it should be possible. Expensive but possible.

    There's nothing more expensive about it than manufacturing conventional carbon or fiberglass blades. You just have to figure out the correct layup. As it is the back edge of the blade goes back pretty far towards the heel. I have a fiberglass blade here that would take the stress. It's not a big deal to install it in a foopocket with the tendons cut off. I can do it if you want to try it. I guarantee you will not like the feeling of the blade trying to pull away from your foot right under the toes, which is what will happen when it's stiff enough to handle the stress without the support of the tendons.

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