thanks arne

this information really got me thinking and i will have to make a change.  starting from a square cross section for the mast will also make stepping the mast much easier.  ill be hunting for a 16’ 4x4 (5 meter long) or two 2x4s to make a solid mast out of.  im sure thats a much better solution than continuing with the birdsmouth mast.

also, im a little embarrassed to say that ive misunderstood the common wood here in south korea for a long time.  it is all imported from russia.  in korean we all call it “so na mu” or pine wood.  but im from california where we use and know douglas fir, redwood, western cedar, and pine, and i foolishly took this information at face value and believed it was “pine wood".  now im 99% sure that the wood is spruce.  here in south korea its cheap, ubiquitous, and i feel that it is nice to work with.  i just wish id had known what the wood was before now.  not so smart for an experienced wood worker.  i should have done a bit more research.

youve saved me a bunch of work!

thanks arne!

i think i will have to reevaluate what ive been doing with the mast.  your simple idea seems so practical and simple.  10 kilos sounds much lighter than the thing i have going now.  im going to compare today.

just to clarify, heres what happened

1. i had to leave my workshop and the boat moved to a marina boat yard.
   
2. the workshop had two things i would not be able to use after leaving: a nice table saw and some very nice, clear, vertical grain, fir boards.  they arent douglas fir, probably hem fir but im not sure.
3. i made a plan to make an 11cm diameter octagonal birdmouth mast and quickly cut them up before leaving, ready to assemble later at the boat yard
   
4. to my surprise the bundle of pieces felt pretty heavy, but its kinda dense wood so i shouldnt have been too surprised.

im really starting to regret cutting up that wood, but i will weight things and think some more.  probably a solid or two piece mast of pine or spruce is a much better option.  maybe even from this point in the project.

david, your idea of the whole young tree is tempting but i would have to order some long whole stick instead of going to the woods because here we dont have those style pine forests.  back home in california/oregon that would be easy!

I wouldn't be bothering with a built wooden mast, at this size. I'd be going to the woods for a small pine tree (straight grained, knot free) that would finish at a diameter of 4in at the partners, which sounds about right for a solid mast for this size of boat. If you then router a narrow groove up it for a very small wire for an LED light, that will also diminish the tendency to develop shakes as it seasons. 

It's not usual to glass a grown mast. One of the soft, traditional oil dressings would be good enough. Glass is used only to give a hard surface to soft timber, it doesn't add strength.

Hi Paul,

My preference for free standing masts of that size is aluminum lower sections and wood top.  I've built a few masts like that - three sections, the bottom two being aluminum tube, the middle section just slipping into the lower for about 6 inches with built-up bushings to make the fit tight.  The top section is made of ripped and glued-up dimensional lumber (making 1/4 sawn pieces on the cheap).  You can then get exactly the final taper you want.  The joints are faired on the outside with a long (maybe 8") fiberglass tapered sleeve so things slide nicely.

This makes an inexpensive and remarkable strong mast if you use the right quality aluminum.  6061-T6, 4" OD base should do it, I think.  Others with even more experience will surely chime in. 

issue #1 - mainsail mast

direct advice and information in a reply or referrals to other sources would be great.

• sail of about 11.6 sq. m. (125. sq. ft.)
• 4.6 meter mast

questions

• suggestions on how to size the mast?  are there some guiding principles on how much mast should be between the partners and the step?  ive read about this before i think but i cant find the info.
• what are the pros and cons of a wood mast or an aluminium one?  im more functional than romantic so a metal mast is fine, though ive started a birdsmouth mast already.  im asking because holding the pieces of the unfinished mast, they feel kinda heavy and maybe aluminium is lighter?
• what rigging concerns should i be dealing with before i finish the the mast and finish the step and partners?
  

thanks in advance!

paul