Tapering a birdsmouth mast.

[paul.norton]

I'm involved in a long-term restoration of a derelict Hurley 22. Practically everything that could be removed was done so before we got her so we have decided to rig her as a Junk Rigged Sloop.

We shall be building the mast ourselves using the birdsmouth technique. The edge opposite the birdsmouth will be tapered in a slow parabolic curve from just above the tabernacle to the mast head.

The wall thickness at the maximum diameter will be 20%; see http://www.duckworksmagazine.com/04/s/articles/birdsmouth/index.cfm If the staves are maintained at the same thickness, then the wall of the mast will, in percentage terms, be much thicker as the diameter decreases.

What is the forum's opinion? As I intend to build a jig to accurately cut the parabola, should I also taper the inside and outside faces of each stave to maintain the 20% wall thickness throughout the mast?

Paul

 

[saltylegs]

The idea sounds good but a lot of work involved, you would diffinately need to shave both the inside and outside faces or else the birds mouth will end up off center.
I chickened out and made mine (for a gaffer) straight with a solid tapered plug about a metre long for the top.

best of luck and take some pics.

 

[prv]

I chickened out and made mine (for a gaffer) straight

A gaff mast wants to be cylindrical (or nearly so) as far as the hounds anyway. Otherwise what size do you make the the gaff jaws or saddle?

Pete