Friday, January 21, 2011

Pathfinder/Chinook Progress report # 2

January 21, 2011
I have now completed all frames, transom, centreboard and centrecase. I found that rather than rely on a multitude of clamps to hold the doublers together I used cheap steel screws which I removed and threw away when the resin was set.

To assist with the speedy orientation of frame parts, when glueing, I used 12.5mm dowels through the frame and doubler.

The centreboard was made from all Tasmanian Hardwoods, mainly Myrtle (Beech) and some Blackwood.

To form the profile of the centreboard I used a design I found on another Blog, sorry I have forgotten who's. This proved very successful. The picture says it all.

I calculated that I poured 26kg of lead directly into centreboard cavity. The only problem I had was keeping the melting pot hot enough to ensure that the lead was still molten when I poured it. The singed areas around the lead are where I directly flamed the lead after the pour to better distribute the lead after the final pour.

To hang the centreboard in the case I used 16mm SS tube inserted directly into the centreboard and centrecase with a shallow rebate to hold a small amont of thickend glue. This not only holds the bush in place but seals the timber from water ingress.

To hold the 12.5mm pin in the bush I made up blank plates from 9mm ply with a gasket of inner tube underneath.

Tuesday, January 4, 2011

The birth of Chinook

The construction of our John Welsford Pathfinder commenced on December 27, 2010 and in less than two weeks we have completed the construction frame, stem and spine plus four of the seven frames. Photos to come.
All frames but not quite the finished article. Transom still to come.