My UL tube project...

[SHigSpeed]

I've been working on updating my UL fins for the last few days. Originally, the platforms were aluminum, but I figured that the material was overly strong and rigid for what was needed, and it was more difficult to work than necessary. Also, the failure of the original design was that the arrow shaft spars for the fabric webbing was too stiff, not allowing the proper curvature to develop and by extension propulsion.

The "OG" fins:



I went to the local TAP Plastic today and got some ABS. Boy is this stuff a joy to work! Lighter, not as stiff, and much less fragile boat skin scary as shiny aluminum.

Also, the overly complicated spar to platform hardware has been ditched for easy, light, and durable zipties! I didn't stoop so low as to use duct tape, but I think these are perfectly suited for this application.

So, I went from tubular carbon spars to flat carbon spars. These as shown are a bit too flexible so I plan on epoxying a second spar atop the first to about half the protruded length to give a "fast action" to them - a little more backbone at the root and still allowing a softer bend at the tips. I also plan to attach the root of the webbing to the platform at the center as during my testing with Rev I the flappy bit near my toes would ride up and down too much.

Anyway, PICS!:







Simple, light, and hopefully effective. I'll be attaching a bungee to the back edge of the fabric foot pocket that will simply pull over the heel. Also, these are designed to be worn over just the neoprene stocking feet of waders. I figure nobody in their right mind would hike up into the hills with a 2 pound float tube with a pair of 3 pound wading boots. I've learned that even my 22 ounce mesh and rubber water shoes seem ridiculously heavy with my "new glasses".

Based on the weight that I'm seeing now and approximating the mass of the stiffening of the main spars plus the bungee, I'm guessing the total weight of the pair will come in at or around 10 ounces! That includes the extra ledge behind the foot pocket which is left on here out of convenience (the stock I had was 8" wide, though the design was for a 6" deep plate). I think the ledge does add a bit of comfort putting the pressure of the up stroke more on the heel than in the arch of the foot, but I may either trim or get rid of it altogether to save another ounce off of the pair?

These will not work very well with donut tubes as they are designed to be slipped into while fully afloat. Not durable or ergonomic enough to really waddle around shore in. Still, should be a piece of cake to get into from an open-front tube. I will say a leash or a floatie should be considered as I don't believe they'll float. I COULD build in a nice air bladder into the web? Nah...

If you don't mind taking zipties with you and "building the fins" at the lake, these should pack up very tidy as well, though hanging them from the pack shouldn't really pose any problems. The spars can go in your rod tube, and the rest stack flat and fold up.

I like.

_SHig
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