Large wooden masts

[daveyjones]

I would be interested to hear from anyone who has experience of building a large (30 ft upwards ) mast in wood, particularly from a solid tree. I am about to do so, and would welcome some advice. Similarly, if you know of any good books on the subject, as I have not found anything despite much research, please let me know.

 

[Peterduck]

The California Redwood masts for the replica 60-ton "Enterprize" were built from solid trees. A deep saw cut was ripped up the entire length of the trunk to provide a weak place where tangential shrinkage would open up in a controlled way, rather than in a haphazard way. When the trunk had finished drying a spline was glued into the sawcut and the shaping of the mast was done in the usual way.
Peter.

 

[ctelfer38]

I have also researched this recently; but I do not claim to be an expert. What I do know is that a solid spar needs to be sawn longitudinally and turned end to end and reglued before profiling - this is to prevent warping. You will also need a well drawn plan for all of the fittings - spreaders, mast furniture and pressure/load bearing 'hotspots'. Main timber choices are Sitka Spruce or Douglas fir. Finding timber big enough for a 30ft solid build might be very difficult - hence the prevalence of laminated/glued masts made up from smaller timber - the latter arguably stronger as well. Try googling Collars and Noble masts - these two firms are in the wooden spar construction business and you might well gather some more information there. Someone with more hands on experience will probably be along in a minute to offer better advice. My own project is remasting with a 22metre wooden mast build in glued (Douglas Fir) pieces to a professionally drawn plan. I wish you luck with yours. /forums/images/graemlins/cool.gif

 

[oldfrank]

Happy to help. My own boat has a 50', largely hollow, wooden spar - but laminated fron ten pieces of sitka spruce. It's also counterbalanced with lead but that's another story.

Excelsior's mainmast is a larch, grown pole and a bit longer. No question of cutting and turning a traditional mast. The key is to find slow growing timber with a large number of close growth rings. Salt helps to preserve them (tell that to the Cutty Sark). Excelsior's first mast after the 1986 rebuild was Douglas and only lasted six years.

You will only find really good grown poles as close as you can possibly get to the tree line. Trawler masts in the olden days were fashioned from pitchpine poles. Practically, these are no longer available - today's pitch pine is grown too quickly for longevity. You need to go and find a stand. Happy hunting.

Old Frank!

 

[Transcur]

It really depends on how much you want to spend. I know a lot of people have used poles imported from scandinavia and then planed them up to shape.

www.caldersandgrandidge.com

The above people supply poles for BT, Electricitg Board etc. I bought one 12 meters long, 11"at the heel and 5.5 at the top. Price was very cheap(less than £250 delivered) Very pleased with it so far after 6 years. A few small drying shakes. Was well treated with linseed etc. Took a couple of days to make.

 

[nmiller]

Hi
You asked about books. The eighth edition of Skene's Elements of Yacht design edited by F S Kinney has some useful information, and the standard work "Boatbuilding" by Chapelle has a good section on shaping the spar.

 

[ctelfer38]

Any idea why the Douglas fir did not last? /forums/images/graemlins/cool.gif

 

[oldfrank]

Grown too fast. The more growth rings, ie; the slower grown and older the timber, the slower it will rot.

 

[Cornishman]

In 2006 Peter Allington fashioned three topmasts at Cotehele Quay for the National Maritime Museum to be taken to Bristol and installed on the Great Britain.
Here you see him carefully guiding one over Cotehle Bridge to the lorry which took them up the M5.
Peter is now retired but can probably be contacted through the NMM at Falmouth

 

[Gunfleet]

This is a location so secret Google Earth have put a suspicious square cloud right over it. What are the Cornish planning down there?

 

[Cornishman]

National Trust - closed for the winter. Come back at Easter

 

[nickjones]

Go to the people who know - and who better than the MD at Collars who was very helpful to me over my enquiries about (albeit shorter) masts. Tel:01865 341277

 

[Seanick]

I have a one year old mast for sale, 45' long, 91/2" at deck, tapering to 5" at the head. Made from a new pole supplied by Calders and Grandige. They use Norwigen Pine, grown in the Corailian (sp?) forest. Mine was 120 years old, and a ' 15m light' I am making another larger one from the same source. Takes about 8 days.

 

[daveyjones]

Thanks all for the contributions. I live in mid Wales. and the local Forestry commission assure me that there will be no problem supplying trees of a sufficient size (mainmast is the biggest at 48 ft long and 10 ins at base) I intend to use Douglas Fir , as it is cheap and readily available. I was hoping to find a book which tells me how to fashion the mast from the tree, and such things as whether I should let the log season after stripping the bark, and for how long. Also does it need to season at all? The design calls for solid spars of Douglas Fir, and being gaff rig, they would be more suitable, also less work than gluing a mast up from small pieces. Besides, if I cock up the work, it won't break the bank if I have to buy another tree, and I am hoping by starting on the small spars first, I will be skilled enough when I get to the big ones. I assume timber should be cut in the Autumn, as the sap content is lower, and the Forestry people assure me I can go with them to stand, and pick the trees myself. I'll check the references mentioned above, thanks again.