Thread: To bolt or not to bolt

Will be watching with interest but can't help with your query. I plan on building a Phoenix when I finish the renovations, the new house and the car restoration.

Rickey

You can try the wheels thing, but the first plank you "hang" (read force) will easily move the wheels (even if locked) and the whole assembly (strong back, boat, etc.) I too like rolling strong backs, but for planking operations, you'll need to stoutly fasten it down. The term strong back should give you an idea of what it must endure.

Thanks guys, looks like I will be taking the Hilti to the new floor and epoxying in a few nuts. Rickey, it
sounds like we should be finishing our boats at about the same time!

A frame bolted/glued etc securely fixed is nice and the preferred method, but that said you can stiffen a strong back significantly by increasing the depth of sections. Consider a strong back with 4" by 2" compared to a 10" by 2" beam. Deflection is proportional to the section inertia and to find the inertia we use the depth cubed times a few other things. So 4" cubed is 64 while 10" cubed is 1000 so you get 15.6 times less deflection for the same load. While your strongback will be heavier using some 10" by 2" old hardwood rafters or something you can get a very stiff frame without bolting. I am part way through my 26' carvel planked and used two 8" by 2" rails old Oregon verandah bearers on my strong back and I got about 3/16th inch flex when the keel etc was clamped down allowed for by adjusting the moulds. On your phoenix if you used 10" by 2" I reckon the flex would be insignificant and after all how accurate is your boat going to be. Its not a piece of furniture, its a boat.

Thanks for the advice Wizened, I have a length of 300 x 45 lvl left over from a job that I intend to rip into two for the strong back along with various other offcuts/left over lengths of treated pine etc. I'm hoping that it may be heavy enough to get away with not bolting it to the floor.
The plan with this build is to use pretty much only timber that I have on hand. I occasionally find a nice bit of tight grained old growth oregon mixed in with the plantation grown stuff when I'm demolishing decks and pergolas that I can't bear to put in the skip. Recently I pulled down a pergola that was predominantly built of Alaskan yellow cedar which was stunning after a run through the thicknesser.

Matt