Friday, December 18, 2009

Birds mouth spars... but maybe not.

Since I have a couple of masts to build, more than a passing moment has been dedicated to thinking just how to build them... Do the words "cunning plan" resonate?

These days "birds mouth" spars are pretty popular as they are pretty easy to make and  low on material wastage. The downside is that the masts are heavier at the top then they need to be.

Back when we built the first Loose Moose we looked into a spar builder who did Bird's mouth spars and he sent several slices of a mast to show off his work and they all failed on the glue lines... So instead, we built our own and went with the as-designed Bolger  simple box mast that worked finest kind!

There is a lot to be said for Bolger's use of Herreshoff's favorite way of building a mast as it is easy to build and pretty light when all is said and done. Right now there is a very good chance that the new masts on "So It Goes" will be this sort, albeit with a bit of carbon thrown in for good measure.

Speaking of carbon though, there is a thought which keeps running through my head thinking about the rather awesome wing masts done by Gold Coast Yachts here in St Croix who use no carbon but build up a mast using 1/4" Fir and glass (with a whole lot of smarts) that has my "There has got to be a better way" genes seriously kicking in...

For those interested in doing a Birds mouth spar, a must read article and calculator set can be found over at Duckworks Magazine (always interesting stuff) in their "Bird's Mouth Spars Revisted"  which is all the info you really need to get rock and rolling! Throw in a router/shaper bit designed for doing Bird's Mouth profiles and you'll have everything you need!