Hi Krusher, I get what you’re saying about the ‘ Da Fin’ presence in Hawaii, they prolly made a deal to supply the Lifeguards and buy pro endorsements that are impressive, but it doesn’t always equate to public popularity, even tho that’s the aim of endorsements.
Same with modern bodyboarding fins, certain companies made it their business to dominate the sport since the 80’s and with amazing sales at that time, they looked to be the fin answer for most.
However, it always comes back to repeat sales. Someone can have a pair of Churchill’s in their garage and proudly drag them out 40 years later, but if they didn’t like them in the 80’s , they prolly don’t like them now and they might’ve hung on to them because they’re not cheap. I hate throwing out crap even if I hate it because I’m hoping something will change and it’ll become useful one day. Much like all the crap in my garage.
Repeat sales are the best indicator of whether a fin is successful. If you’re Da Fins were lost , would you buy another pair ?
Sure you’d buy a replacement for a lost fin because you’ve already got 1/2 the set, but if you lost both....
Would you immediately buy the same or look for what’s new ?
After 25 years of trying out various fins, I have now repeat bought The MS vipers several times. Initially, I was buying the yellow dot stiffer pairs, but found after walking in and out of the water across sharp rocky reefs they would eventually crack across the foot pocket (this is use and abuse on my part) after a couple of years of heavy use, I then bought a pair of the orange dot, which i find easier on the legs being softer (more flex like a fish's fin) and they have survived the rock abuse for much longer.
I had a pair of dafin and after less than 10 surfs they snapped across the heal straps (which are the thinnest heal straps I have seen on a fin) a few years later I won a set in a comp and gave them to a friend he lasted less than 5 surfs before they snapped too. I would no trust them as a lifeguard fin, if the straps snapped which in a rescue it could mean someones life.
Mike stewart also supplied fins at a very reduced price to my friends non profit surf school for girls, https://www.facebook.com/search/top/?q=wahine%20mike%20stewaert&epa=SEAR...
Send me your dinged, damaged, and yellowed.
I won't laugh at your graphics skills, they are far superior to mine. As much as I think your idea eliminates the pocket/foot issue, the physics of a fin at the end of the foot would seem to be more likely to generate greater propulsion, than a fin attached to the shin. I looked into improving technique a while ago and contacted Rob Case from www.surfingpaddling.com/ who offered the following suggestions, which I thought some might find of use.
"The finning technique depends on how long your blade is. You kick a lot different with a freediving fin than you do with the typical bodysurfing/bodyboarding fin.
However, there are some common fundamental kicking techniques across all:
Use your whole leg – initiate the kick from your hip flexors, let the fin build up the water’s resistance on the blade, and then release it. I like to imagine my blades grabbing and then whipping the water back.
o Be careful of too large of a kick. Since we are always trying to minimize drag, if you kick too low or too high, meaning the foot is raised higher or lower than your body and board, then you are going to adding drag.
· Thus, small quick kicks are used when sprinting and slightly longer draw out kicks are used when paddling/kicking back out. But try and keep the kicks within your horizontal profile (what you look like when you are viewed from the side at the waterline.
· Point toes is also a key technique as well as kicking on the up AND down stroke (use your quads and hamstrings)"
I always prefered Duck Feet to Churchills because of the power they had. That works against someone who hasn't used fins for 15 to 20 years. I played water polo in high school and many of my contemporaries became lifeguards here, a lot of them used Churchills when we body surfed. Mark Cunningham was a strong supporter of Da Fins, he's a few years older than me and played water polo for our rival school. Whatever works for the lifeguards is good enough for me, but I rarely use fins these days, so I think I'll need to put the time in and get my legs back in shape.
It's like paddling - you can get out of shape easily. With your background it will come back. A small fin would be better if you want to use it to body surf back in. I had read once about a guy who kept a pair down the back of his shorts - can't see how comfortable that would be. You'd also have to consider how easy or difficult it would be putting a pair on, in the water.
Surrfoils once made me a small inflatable mat, that would fit in a pants pocket or small bag and could be inflated to catch waves in on.
So my theory is that a flipper works by moving thru the water at an angle and that pushes the water back and the wearer forward.
Obviously the more water going backwards the better you move forward but fins are basically a flat plate with lots of sideways washout.
daFins have a small vertical ‘horn’ more than a strake up near the foot but a Scubapro fin has a pronounced curve edge near the trailing edge and these fins get rave reviews about their drive.
If you take an average flipper blade of 45 sq in and guess there’s a loss of 30% due to sideways washout and vortices then potentially it’s possible to have the same drive or higher from a small fin due to higher efficiency.
Maybe the loss of drive due to a flat blade is higher than 30% , it could be 70% .but you don’t want a larger blade as it’s more tiring to use but a more efficient blade would have a similar feel as it’s channeling more water rather than slipping thru it.
So why do fish/dolphins/whales not have these curled edges to their fins, are they suffering from sideways washout?
maybe you would like these https://www.leblonfins.com/products/leblonfins-flex
Next time I see a Narwhal on a bodyboard I’ll ask him.
I’ve seen those LeBlon fins, I wonder if they could’ve gone further to limit the sidespill.