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Re: Bungie layout
By:mike allen --->
Date: 2/13/2001, 8:55 pm
In Response To: Re: Bungie layout (Liz Leedham)

: On the subject of bungies to facilitate paddle float re-entries. The best
: re-entry fastening I ever used was on my Feathercraft K-1 folder. A piece
: of webbing ran from just behind the cockpit and along the mid-length of
: the boat for about the width of a moderate sized paddle. You jammed the
: paddle under the webbing as well as under the bungies and it seemed solid
: as a rock. Any thoughts on how this system could be copied into a new
: stripper (still being built)? Would it place too much strain on the back
: deck, be problematic for attachment, look downright ugly or any other

Hi Liz

No great experience here w/ paddle floats just ideas. I had some time to consider this on posts last wk.

Webbing as a material should be structurally fine for this purpose. The main problem for me is visual in that 1/ webbing is wide and therefore obtrusive and 2/ comes in widths that compare and thereby disconcertingly compete in scale with strip widths. It seems to me that yo can get the same xsect area or strenght in a round less visually impacting line. Probably BS for most, but then why the pics?

At first blush a centrally mounted line seems fine but as soon as stress is involved big problems jump out. If no stress is involved and the central is just a guide made out of flexible bungie no big deal. But the layout you have is completely backwards and I would guess that the reason it seems ok, is that most other systems out there are even worse.

I’ll stick my neck way out and guess that the perimeter lines(above the shear) are single, bungees and abt 1/4in diam( maybe even continuous?-) and especially they’re probably just tight enough to lay straight and easy enough to grab and deflect. (I’m gonna be killed on this one!)

But the important point is that these lines will easily deflect. This means all the forces will be translated to the tight central webbing – and thereby to its 2 fittings. Cadging some of georges first order analysis , assuming a foam paddle float of 15# and a paddle of 7ft(6ft uplift lever arm), whenever the float gets buried in water (absolutely disregarding the paddler and the yak loads) there is an uplift force of min 50# on each fitting if the webbing is slack. If it’s tight, its way more. If you’re in waves and racking occurs and assuming 15# the same horiz force, the forces get to 125 to 250 additional # depending on the pt of rotation taken.

Now my paddle float is air and has 30-40# of floatation, and othe pple have these also, so the forces go up 2x esp if the yak is swamped and horrible conditions And I believe feather craft advertises thinner cloth for the decks.

So take your yak out, hang it upside down somewhere and you and your sister start swinging on one of those central fittings. Will the fabric, fitting, deck, coaming, or hatch(if nonfabric yak) be compromised? What if you were in major conditions. Is the safety measure designed to be safe?

I think the webbing should be on the sides (and the bungee or some paddle aligner on the ctr). The uplift lever arm is halved and the racking lever arm is a quarter or much less. Simple move, big impact.

Seaward does this with 2 outside webbing straps. Each web has a quick release buckle and a free slip end to tighten. Pull on the quick release to relas the paddle, pull on the slip end to tighten, lift up the slip buckle to loosen. Good system. Could be better if they turn it around and put the pulls toward the cockpit, so you can more easily tighten when deployed. Suspect the buckles under stress, but the stress is less than the previous eg. Would be better w/ a cross paddle guide and a hook fitting on ea free end, like discussed in the prev. post for either the shaft or a stirrup.

For my purposes, at this stage, I’d use the line layout in the prev. post, but would look at different fittings to achieve some of the flexibility that seaward has like maybe som sort of integral jams. I like the redundancy but might sacrifice it for one set of 5/16nylon lines for visual.

Like a good looking strong flexible approach.

-mick

Messages In This Thread

Another one hits the water *Pic*
Nick W -- 2/12/2001, 12:00 am
Re: Another one hits the water
Roger Nuffer -- 2/15/2001, 12:11 am
Re: Another one hits the water
Ray Port Angeles -- 2/12/2001, 8:57 pm
Re: Another one hits the water
mike allen -- 2/12/2001, 6:15 pm
Re: Bungie layout
Ben Staley -- 2/12/2001, 7:46 pm
Re: Bungie layout
mike allen -- 2/13/2001, 12:23 pm
Re: Bungie layout
Liz Leedham -- 2/13/2001, 1:22 pm
Re: Bungie layout
mike allen ---> -- 2/13/2001, 8:55 pm
Re: Another one hits the water
Ben Staley -- 2/12/2001, 1:50 pm
Re: Another one hits the water
Geo. Cushing -- 2/12/2001, 1:04 pm
adhesive remover
Paul G. Jacobson -- 2/13/2001, 2:43 am
Re: Another one hits the water
daren -- 2/12/2001, 9:25 pm
Re: Another one hits the water
Geo. Cushing -- 2/12/2001, 10:13 pm
Wow...a real beauty..enjoy!!! *NM*
Bob Deutsch -- 2/12/2001, 11:36 am
classy! NM *NM*
Jim McCool -- 2/12/2001, 8:39 am
Re: Another one hits the water
Ted -- 2/12/2001, 12:56 am
Re: Another one hits the water
Nick W -- 2/12/2001, 2:45 am
Re: Another one hits the water
daren -- 2/12/2001, 12:36 am
Re: Another one hits the water
Nick W -- 2/12/2001, 2:35 am