SHig's Superlight Packin'tube Project

[Scott V]

I'm looking forward to building a "strap-on" version.

_SHig

I will do my best to refrain from making any comment.

[SHigSpeed]

I will do my best to refrain from making any comment.

It appears you have failed!

In all seriousness though, I'm wondering if having this thing attached to one's person would be too limiting to mobility? Maybe if made narrow enough...

_SHig

[SHigSpeed]

What about a seat similar to the ones on the north fork frameless pontoon boats. Something that could be detached easily and could roll up with the tube. Not sure if that would add to much weight or not and couldn't be used as a pillow.

I'm thinking in similar terms to those however they do require strapping down to the tube somewhere. My fear is leaning back too hard without thinking and tearing out a seam and losing a lot of air fast. The safeguard I have is to just use thin straps that would fail before the seams do, however that can look like poor quality to some. Another option is to use breakaway connectors like those found in safety lanyards so you can only load it with so much tension before they pop free - worst case I could see someone flopping back and flipping! Nah, I guess not with feet and fins in the water.

I don't have the faith that people will understnd the major design compromises that are required to achieve such low weight and compactness. Maybe I should?

_SHig

[OceanSunfish]

I'm thinking in similar terms to those however they do require strapping down to the tube somewhere. My fear is leaning back too hard without thinking and tearing out a seam and losing a lot of air fast. The safeguard I have is to just use thin straps that would fail before the seams do, however that can look like poor quality to some. Another option is to use breakaway connectors like those found in safety lanyards so you can only load it with so much tension before they pop free - worst case I could see someone flopping back and flipping! Nah, I guess not with feet and fins in the water.

I don't have the faith that people will understnd the major design compromises that are required to achieve such low weight and compactness. Maybe I should?

_SHig

Yes, you should. It's well known that "every boat is a compromise".

[SHigSpeed]

Okay, though there is already a thread open for the fins, I'll just start logging it here...

I've been working on updating the 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

[Kneedeep]

Brilliant!
How about Velcro straps? They could serve multi-purposes and no hooks to puncture anything.

[SHigSpeed]

Brilliant!
How about Velcro straps? They could serve multi-purposes and no hooks to puncture anything.

I HATE Velcro. Can't be glued, wears out, frays. UGH!

Tell you how I really feel, right? :P

The only downside to the zipties is that line can tangle on it if you're not careful enough to keep it out of your feet.

Oh, BTW:



How's THAT for sticking the landing? Doubled up spars included - though I tried gluing them and they were TOO stiff. They're just layered in there now. All up, bungees and ready to test.

_SHig

[SHigSpeed]

Took the tube and fins to a Mother's Day pool party and waited for a lull in the water activity.

Verdict? The fins work GREAT! The right amount of flex to get easy propulsion and very easy on the ankles. No feeling like the spars are overstressed or at risk of breaking. I seem to be able to get a good clip going but in a small pool it was hard to tell absolute speed.

The bungee worked well if not a bit loose. I had a cord lock adjuster on it initially but the one I had wasn't tight enough not to slip under tension. The one thing that needs attention is the spar location fixing. I has hoping that just the tension on the zip ties wouldn't allow them to shift, but with all the flexing they did. The main spars shortened up and the cross spar that holds the mid-web at the toe wiggled free and sunk to the bottom of the pool. I had to have one of my boys dive down and retrieve it.

I have solutions for all of these issues, but they all make it more difficult to do a field tear down off the units without snipping zip ties.

I really would like to have an easy "inside the pack" solution but I suppose PITA is better than none, and none won't technically be the end of the world.

I'm not giving up yet but the most important design goals (weight and effectiveness) seem to have already been met.

_SHig

[SHigSpeed]

Fins Update:

I've been continuing to work on the fins since I pool tested them last. Unfortunately this means that I haven't done any tube testing, but the two really go hand-in-hand.

At any rate, I've been working to tidy up the design and shave some more weight off.

First off I rounded off the heel edge of the plate to remove some excess weight, then I cut out another disk under the arch of the foot within the pocket to lose a bit more weight. I was a bit leery of losing the structural rigidity of the disk material, but it turns out that the webbing root spar does a great job of adding some backbone to the front edge of the plate.

I also cleaned up the webbing to be a one-piece affair and glued on some stoppers to fix the geometry better.

Finally, I added a cord-lock to the bungee to allow easier adjustment, though it does add 0.2 ounces to the affair. A simple "tie a knot and forget it" would do the trick in a pinch.

Pics:





Down to 9.3 ounces! I will be downsizing the foot hoop spars a size or two and I can use a thinner fabric (this is a 200D vs 70D that I make the tubes out of) but I'm not sure if I can bring the weight down to under 9. Regardless, I think it's acceptable.

Finally, here's a photo of it on over a neoprene stocking foot. In this photo I have a thin sheet of foam between the foot hoop and my foot. I suspect that this volume of foam is all that should be needed to float the fin should you ever drop it or have it come off.



I have a trip to Yosemite planned with my boys this weekend, but I hope to hit a couple of my favorite walk-in lakes the following and get some float time with the setup.

_SHig

[Kneedeep]

You have a great/safe trip!
Look forward to your report.