making 2 alpaka packrafts into a double

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Derekoak
Posts: 5
Joined: Tue Feb 19, 2013 6:23 am

making 2 alpaka packrafts into a double

Post by Derekoak » Sat Aug 17, 2013 10:48 am

We wanted to use a double packraft as I am pretty sure there is a big discrepancy in our speed. Alpaca's double do not allow comfortable double kayak paddling so we decided to get a single to try out. Now we have one it occurs to me that if I added 2 extra lash points forward of the stern ones in a similar pattern to the front 4 and got a sheet of high density polyethylene similar to the stiffeners in some rucksack hip belts and made 8 reinforced holes in it to suit the 4 lash points at the front of one raft and the 4 made at the back of another and lashed through the sheet at every point now the 2 rafts will act as one. On a lake the rafts will go straighter and speed could be higher. If a problem occurs either rafter could untie quickly. I imagine rough water would cause problems. I have read Erin's book and understand that something similar can be done lashing a tree underneath as keel. This idea is more flexible and the sheet would roll up and be stored with a raft. I do not think 2 foot square sheet of say 1mm HDPE would weigh that much. Has anyone tried something like this? We have not at the moment got 2 rafts to try this with.

Derekoak
Posts: 5
Joined: Tue Feb 19, 2013 6:23 am

Re: making 2 alpaka packrafts into a double

Post by Derekoak » Tue Sep 17, 2013 11:37 pm

I now have an alpacka and a yak to put together and it is clear that my first idea needs a very big piece of nylon membrane, so idea 2:
a plastic membrane with only 4 holes in it suitable for the back anchor points of one raft and the front 2 anchor points of the other. You could perhaps do away with the membrane and just join the anchor points fore and aft with cord and add both diagonals. You still need to glue new anchor points where I suggested for idea 1( in the region of the points needed for the rear thigh straps that people fix). Then 2 compression rods paired with nylon cord or webbing for tension between the rafts one port and one starboard. The rods need to be about 3 foot long. I Was thinking of trialling with carbon fibre walking poles, but something lighter might be possible. I need some way to ensure that the rod ends are captive so they cannot possibly puncture a raft. Maybe a reinforced webbing pocket at each end of the webbing strap to enclose the rod ends?

Derekoak
Posts: 5
Joined: Tue Feb 19, 2013 6:23 am

Re: making 2 alpaka packrafts into a double

Post by Derekoak » Wed Sep 18, 2013 12:44 am

I now have an alpacka and a yak to put together and it is clear that my first idea needs a very big piece of nylon membrane, so idea 2:
a plastic membrane with only 4 holes in it suitable for the back anchor points of one raft and the front 2 anchor points of the other. You could perhaps do away with the membrane and just join the anchor points fore and aft with cord and add both diagonals. You still need to glue new anchor points where I suggested for idea 1( in the region of the points needed for the rear thigh straps that people fix). Then 2 compression rods paired with nylon cord or webbing for tension between the rafts one port and one starboard. The rods need to be about 3 foot long. I Was thinking of trialling with carbon fibre walking poles, but something lighter might be possible. I need some way to ensure that the rod ends are captive so they cannot possibly puncture a raft. Maybe a reinforced webbing pocket at each end of the webbing strap to enclose the rod ends?

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