Doug fir pole mast

[De_sv_Taz]

I am facing similar decisions with masts for a traditional unstayed junk... reluctantly considering wood due to difficulty finding industrial Al pipe in the requisite wall thickness and diameter.

The problem I have -- and it may be the same for the gaff rig owner -- is that industrial Al pipe in larger sizes comes only in even inch OD, i.e. 6 8 10 12 inch OD.

What I need is 9 inch OD or better yet 9.25. 9.5 would be a darn tight fit.

Then there is the problem of taper. To get some taper into the mast you want to sleeve sections of pipe with gradually diminishing OD. However, not many sizes of industrial pipe seem to sleeve tightly enough to make a really good mechanical fit. And if you start welding on T6 you lose the hardening and almost all the strength at the weld locations. Re-annealing is a major project for an entire mast.

Anyway, it's a tough problem if you need very stout, round x-section poles such as for a gaffer or junk. Steel sheet can be custom-made into faceted masts on a metal break, but the N-sided poles are (a) very heavy and (b) difficult to taper and (c) don't maximise material at radius.

My latest desperate notion is to skin a doug fir pole in thin aluminium, i.e. completely encapsulate the pole except for the butt end (I have a steel boat and don't want the aluminium in contact with the steel step). This would protect the DF from weather and eliminate the yearly rituals of oiling, and also provide abrasion resistance where the parrels and battens rub against the mast. I have no idea if this is realistic -- can Al sheet be bent closely enough to the mast to be a tight skin? can it be welded without too much charring of the wood beneath? can the seams be ground down smooth enough on thin plate w/o gouging through the metal? will it be too heavy? ... but I am thinking about it.