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How does everyone feel about supporting seats on a lapstrake plywood boat directly to the hull and a rig, without the use of ribbands-ledgers?
5 replies:
RE: Ribbands and Seat Support
That depends entirely on the boat, the seat type and the paddler's weight.
The hull should be just fine to support the seat itself, since there's lots of square inches to spread the paddler's weight over and it's all supported from underneath by the water anyway.
The ribs, on the other hand, will have to support the concentrated weight of the paddler leaning backwards. Depending on what else the rib is being asked to do in the design, that may overload it in some situations.
So, got any more info for us?
Laszlo
RE: Ribbands and Seat Support
Thanks Lazlo ... Many rowing and sailboats I see out there appear to have eliminated the fore-aft ledger-ribbands (I'll call them). It looks to me like this can potentially be a weak point, especially where one of the "seats" is actually a bench for the unstayed mast. I may be obsessing about this ... But, am curious if some builders have decided that the nature of the lapstrake hull adds so much strength that the ribbands are not needed. This certainly makes for a "clean" look, and makes finishing and maintenance easier. What I do see is an attachment to the ribs and short ledgers under each seat, attached to the hull. I am not considering small paddle craft, in this curiosity, but small 10-20 sailing-rowing craft. Yachats
RE: Ribbands and Seat Support
Yachats,
OK, I got you now. I was thinking you were talking kayaks. In fact, my sailing dinghy (though not lapstrake) does exactly what you're saying. The center seat sits on top of the center rib and is supported on the sides by cleats (your ledger-ribbands). My mast partner uses the same construction.
I believe that CLC's Skerry does the same, except that it uses a thickened epoxy fillet instead of the cleats.
Laszlo
RE: Ribbands and Seat Support
Thanks again, Lazlo ... I'll get over my concerns and go ahead with the supports and braces, without another "running ledger". One can always add them later, I suppose ... The're also great place to lash one's bumper lines, etc ... :?) I appreciate your help. Yachats
RE: Ribbands and Seat Support
» Submitted by Yachats - Sat, 12/26/09 » 10:59 PM
Hey, this is Yachats ... I mis-typed ... it is "a RIB" ... not, a RIG (opps!)