A Strongback for uneven ground - any ideas?

[Trevlyns]

At last I'm ready to start work on my 8.5meter proa but have hit a snag trying to build a strongback for the very uneven ground at the boatyard. The ground undulates in every direction and trying to get a nice level surface for the frames is proving annoying!

Any ideas or links would be most welcome.

Best!

[Petros]

I have had to do something similar in my yard, but on a smaller scale. I suggest built the strong back in several sections on a level surface like a smooth concrete slab or garage floor. built it stout enough to hold its shape, and transport it to your boat yard in sections and assemble it there, shimming it level with blocks or wooden legs. Just make sure your leveling shims/legs are close enough together and attached securely enough so they do not shift or move once the weight is on them. If it is large you may want to rent or borrow a lazar level, normal builder's spirit levels should be good enough for smaller boats I would think (about 7-8 meters).

Good luck.

[charmc]

I would go with the system Petros described. I've had to do similar work, repairing large machinery outdoors on uneven and/or soft ground. If the strongback is sturdy enough, shimming and individual leg extensions will work.

Don't forget to post pix as work progresses.

Good luck, Trev!

[Trevlyns]

Thanks Petros and Charlie for solid advice as always.

I like the idea of adjustable legs and will try sort something this weekend.
I've hoisted out and serviced the old Kodak Brownie so pics will follow shortly!

Thanks once again fellas.

[waikikin]

Trevlyns, I like steel for a strongback- on uneven ground you can simply drive some angle stakes into the ground(after checking for pipes/wires etc) & weld off the longtitudinals to them at level & strait, also have plates with a triangle cut out to give some bearing area to the earth, if your needing a trailer for the boat it can be made to serve as the strongback for construstion also. All the best from Jeff

[Trevlyns]

Thanks Jeff - not really practical in my case however. The terain is loaded with rocks and small stones with concrete chucked in to smooth the potholes --- much like South African roads, come to think of it!

[masalai]

Use what house-builders do, - a tight string line - and a long 'level' as the mark for the zero/keel line... Build to that alignment...

If you cannot get either a garden hose filled with water will give you two points in the horizontal and a string line between them... Sean lost his string so maybe it is around your way in the hardware store...