A Photo & Discussion Forum for Wharram Design Enthusiasts
I am making a wheel steering set-up for my 31'. I have made it from offcuts knocking about my workshop (hard to get stuff at the moment) and to suit my tooling (small engineering lathe/woodworking gear), so haven't bothered looking at plans.
The drum is 200 long x 150 diameter laminated elm with 6mm thick tufnol discs 200 diameter at the ends, on a 25mm bronze shaft/stainless bearings.
I have set it up on the bearings which are housed into shells housed into the ends of a thick ply box and have been playing about with it at this stage to see how the rope will behave on it in use. The drum spins well and true but from what I can see the rope will form riding turns if it is just wrapped along the drum. So is the rope fixed in the middle, or arranged in some way to stop riding turns? How many turns are best used, should they cover the length of the drum? I am assuming 5mm or 6mm diameter dyneema will be used as I have some spare.
Any advice? Thanks- Ian
For the record I've spent a few (more) happy hours trawling the back pages here and elsewhere, and eventually found this:
On here Mike Lynn said that the Wharram set -up on Pahi 42 was 3 turns each direction, 5 drum turns lock to lock. Photos seem to indicate two narrow drums are used side by side.
Ann Clement said that Neville had fixed up a tufnol drum reclaimed from something else, fixing the rope in the middle and a couple of turns each side, and using waterpipe (I guess the blue mains- water pipe is very low friction) for directing the rope, presumably to the blocks.
Elsewhere (monohulls) I have found people using a divider on the drum and others winding the rope fixing it in the middle.
It would seem that an easy- access facility to deal with any problems is a good idea. I am also leaving the tail end of the shaft coming out the other end of the housing opposite the steering wheel overlength for anything else I decide to put on it ( but can always saw it off if it gets in the way).