Seth Wood
01-09-2003, 08:11 AM
I'm trying to lay out the bolts (floor and "scarf") for the fwd. backbone and stem assembly of the 30' sailboat I'm building. The backbone is white oak, 9 1/8" wide; floor bolts every 24".
I'm finding that it's difficult to lay out scarf bolts to hold the timbers together across the joints, that don't somehow cross the vertical floor bolts (also running through the joints, of course.)
This is only a problem in one or two spots -- but they seem to be critical. I'd like to get a long bolt pulling the joint together, but it would have to cross a floor bolt.
Staggering both the floor bolt and the scarf bolt would keep them 2-3" apart (side-to-side) when they cross, and they would hit the outer face of the stem about 4" apart (fore-and-aft).
I worry about weakening the wood with lots of bolts, or bolts too close together. I've pored over Chapelle, Pardey and McIntosh, but haven't found any definite recommendations. It would appear that angled drifts would work, but I'd rather have the through-bolts if possible.
So, in short: is there any easy way to tell when there are too many bolts going through this material? Any safe rules of thumb? How have other builders dealt with this floor bolt vs. scarf bolt issue?
As you can see, lots of time scratching my head in the boatshed last night leads to a long question this morning. I'm grateful for all suggestions. Thanks.
I'm finding that it's difficult to lay out scarf bolts to hold the timbers together across the joints, that don't somehow cross the vertical floor bolts (also running through the joints, of course.)
This is only a problem in one or two spots -- but they seem to be critical. I'd like to get a long bolt pulling the joint together, but it would have to cross a floor bolt.
Staggering both the floor bolt and the scarf bolt would keep them 2-3" apart (side-to-side) when they cross, and they would hit the outer face of the stem about 4" apart (fore-and-aft).
I worry about weakening the wood with lots of bolts, or bolts too close together. I've pored over Chapelle, Pardey and McIntosh, but haven't found any definite recommendations. It would appear that angled drifts would work, but I'd rather have the through-bolts if possible.
So, in short: is there any easy way to tell when there are too many bolts going through this material? Any safe rules of thumb? How have other builders dealt with this floor bolt vs. scarf bolt issue?
As you can see, lots of time scratching my head in the boatshed last night leads to a long question this morning. I'm grateful for all suggestions. Thanks.