Russell Brown Lightship
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Regarding your advice to consider telescoping beams and avoiding tramps, what do you think of a solid platform to lay across the beams to strengthen the structure, to lock the beams open, and to avoid the complexity of rigging tramps? The platform need not be 100% solid if heeled wind load was a concern, but could help the system act as a torsion box with some amount of solid seating area, that could double as a sleeping platform. Straps could lash the platform to the beams.
Could the platform be permanently hinged to vaka and ama and hinged in the middle so that it folds in _ /\_ fashion as the beams are telescoped in? Lashing the platform to the beams would lock the beams from telescoping.
Just a thought
Peter
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Could the platform be permanently hinged to vaka and ama and hinged in the middle so that it folds in _ /\_ fashion as the beams are telescoped in? Lashing the platform to the beams would lock the beams from telescoping.
Just a thought
Peter[/quote]
I guess my concern there would be a single person breaking the boat down for trailering would have to simultaneously collapse the beams while folding the platform. If tolerances were snug with the telescoping beams, getting everything to operate smoothly, especially after years of use, might realistically become a two person job. If you chose this route, perhaps one could first fold the platform (which therefore disconnects from either ama or vaka) and then collapse the telescoping beams.
Attaching the platform to the ama and vaka would entail eight points of connection (four beam + four platform), and make the entire structure extremely rigid… is that better than simply stiffening the beams with the platform atop, and then just having to concentrate on four points of connection?
First of all, if you have not seen them, Paul Bieker put study plans up for the 32’ proa on his blog.
Assuming you’ve looked at those, on to the problems of folding and telescoping.
Tight tolerances are not an issue for telescoping, assuming you do it on the trailer. Mike Leneman’s L7 trimaran uses pulltruded fiberglass ibeams as akas and telescopes nicely, with little friction inside plywood box beams. And as we flew 2 hulls the day I raced on it, I can tell you that the akas are plenty strong when tightened up.
But look at the problem for the proa that folds like Gary’s Va’a Motu. Lets assume that you do not have a pod or safety ama (not a good idea in my limited outrigger sailing experience). Lets assume that a proa’s beam wants to be about half its length center to center (no?). So a 24’ proa is 12’ center to center, something like 13-14’ BOA. Fold that in half and you’re okay—in fact you have a foot and a half left. Not enough for a pod. So the single fold limit gets bumped up against somewhere in teh 28’ range.
Telescoping requires overlap, So max beam looks something like the total length of the aka. Maybe a little less, but now your overlap is getting small. So if your overall beam is 8’6, that’s how long your akas are. That makes the llimit happen at around 20’.
There’s always the swing wing approach—which trades those compromises for an increase in LOA. But now your deck/cockpit to windward might get in the way.
I just did a study on the Scampi daysailor to look at folding and telescoping, and it seems to me that at 12’ each, my akas might be still be light enough to manhandle. And taper fit sockets at both ends, lashed or bolted tight, mean lining everything up plus 4 bolts or lashings might not be that much harder than a folding ama. They’d surely be lighter.
2c.
chris
Skip
Regarding your advice to consider telescoping beams and avoiding tramps, what do you think of a solid platform to lay across the beams to strengthen the structure, to lock the beams open, and to avoid the complexity of rigging tramps? The platform need not be 100% solid if heeled wind load was a concern, but could help the system act as a torsion box with some amount of solid seating area, that could double as a sleeping platform. Straps could lash the platform to the beams.
I’m all in favor of it, not sure a solid platform is required. P52 started life with swing wing arms and a tramp. Never worked very well, part of the problem was my being cheap, a real tramp material would probably have worked better….but. With apologies to Hobie cats and a couple of proa friends of mine it just isn’t all that comfortable or secure and does add to the setup time. P52 ended up with telescoping beams and three planks spanning between them in the space between the pod and float. Worked very well and don’t see a need for change there. Planks were 1X6 cedar with a tee leg on the bottom, bungied into place. An unanticipated benefit was one could be taken off to serve as a gangway across some pretty nasty gunk at Hap’s Cut on the TX 200. I had originally planned on using large dia alum tubing for the beams but I didn’t look close enough at website when I ordered the stuff and it came 6061 T0 (no temper, soft as hell). Now have some really nice LARGE windchimes at house 😉
Current beams are 1x4 boxbeams 1/4” ply webs, work fine sliding in a larger box section built into the pod. One hassle was the hold open latches were built into the inner end of the beams and it required an extra trip into and out of the boat to set the latches during setup. Nomad will have some dropin pins that I can access leaning into the boat.
Cheers,
Skip
[/quote]
I had originally planned on using large dia alum tubing for the beams but I didn’t look close enough at website when I ordered the stuff and it came 6061 T0 (no temper, soft as hell). Now have some really nice LARGE windchimes at house
Cheers,
Skip[/quote]
Made a set of these once with a friend: we spent quite some time figuring out proper lengths, and they ended up ..almost.. in tune. Not sure if they are still hanging, but they were LONG!
Bieker/Brown jester proa just got a build blog at
http://proa32.blogspot.nl/2014/01/approaching-build.html?m=1
I am really exited about this boat and wonder how it will perform againts the jzerro setup with different rig placing and hielkema style outrigger
It looks to me like the bows are a little less fine entry when compared to other Brown boats
And that rudder seems so Tiny to me in relation to the sail area
Yes, they’ve made several posts already. Great fun to watch.
It’s interesting how blogspot seems to serve a different URL based on one’s location. When I link to the blog from Vancouver, I get
http://proa32.blogspot.ca/
It’s the same blog as your link. You are in the Netherlands, right? Interesting.