If you are a dreamer, a doer, a horizon viewer - come in! come in! Announce yourself and let it be known.
The seed of adventure has been sown.

The goal is to take this boat on a trip that no other Wharram boat has taken.
From Great Slave Lake in Canada's Northwest Territories up the MacKenzie River to the Beafort Sea
and westward to the Bering Sea and south to the inside passage on the Alaska and British Columbia coast.

Sunday, October 22, 2006

Current things I am waking up at 5 and thinking about.

1. Should I install the forestay U-bolts now or after the hull is finished. Stainless steel doesn't like to be oxygen starved as molecular level corrosion can occur which suggests installing them after completion of the hull. If I drill the holes later will I be able to seal the holes so water doesn't get at the wood and cause rot. My solution - I'm thinking of installing oversized U bolts now and epoxying them in.

2. What is the true engineering purpose of the diagonal brace Wharram uses. Do they prevent panting of the hullsides (flexing in and out) or do they prevent longitudinal flexing of the hull. If it is for flexing the ones in the middle seem to go the wrong way. (sorry about the photo quality) I've never seen bracing like this in a boat. Typically transverse frames or/and longitudinal stringers are used. Wharram doesn't use these diagonals in his Pahis but does use longitudinal stringers. What to do! What to do! What to do! ..........


Anonymous Jim said...

The aft pair of braces create a tetrahedron when combined with the keel and the second bulkhead. A tetrahedron is the strongest structure there is for its mass. It will not distort.
I dare say the strut (or is it a small panel?) going between the upward angled braces is to prevent panting as you call it and I presume to assist in the compounding of that panel there for added stiffness.

The forward pair of braces are a bit of a bastard child as far as engineering dogma goes. I presume Wharram placed the apex along the stem rather than at either end to place it where he expects the stem to strike floating debris.
The space above the braces describes a tetrahedron but the space below does not (if looking only ar the braces) and is therefore relatively weak by comparison.

If it were my boat, I think I would runt he forward pair of braces from the botom of the stem and the aft pair from the opposite diagonal corners so that from the side the braces go up to the first bulkhead then down. This then describes a series of tetrahedrons.
Beep up hte stem if you want to.

4:24 PM  

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