dcr
Well-Known Member
Which of the above is preferable hull material for a motor boat?
Which is best for seawater - mahogany, teak, pitch pine?
- Thread starter dcr
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Motor_Sailor
Well-Known Member
Pre 1970s Burma teak, pre-war pitch pine, then true mahogany. In that order.
Recent plantation teak, post war pitch pine and all the stuff that gets called 'mahogany' can only be judged on a case by case basis.
Recent plantation teak, post war pitch pine and all the stuff that gets called 'mahogany' can only be judged on a case by case basis.
Tranona
Well-Known Member
Just to add, rot in planking is not primarily caused by seawater, but by fresh from leaks above. The advantage of the materials described above is that they are more stable and durable than others, but still rely on an effective coating to keep them as dry as possible.
Kukri
Well-Known Member
Just to expand a little on that, which is perfectly correct, rot is not the only problem - electrolytic corrosion of metal fastenings is also important.
If you keep a wooden hull free from rainwater and domestic fresh water leaks, and very well ventilated (think "howling draft!") then the timber above the waterline will be at ambient moisture levels and these are too low for rot to start, whilst the timber below the waterline will be saturated with sea water and the osmotic pressure will be too high for rot to start. You will be correct in thinking that planking and framing "between wind and water" is more vulnerable and that is why planking timbers such as elm (traditionally used for the bottoms of canal narrow boats) are not used there.
Teak is not particularly strong, but it is is very dimensionally stable, and contains a poison which discourages rot, Genuine mahogany is also dimensionally stable and fairly resistant to rot. Genuine pitch pine has a LOT of resin in it - if you scrape a square inch or so back to bare wood and are overpowered by the smell of genuine turpentine, you have got pitch pine. If not, you have got the much commoner, and less resistant, Douglas fir, usually sold in this country as "BCP" - "British Columbian Pine".
Beech is dimensionally stable and strong, but rots as soon as you look at it, which is why tools are made of it but you never see it in a boat.
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nortada
Well-Known Member
Couldn't have put it better myself!
ianc1200
Well-Known Member
Re "Genuine pitch pine has a LOT of resin in it - if you scrape a square inch or so back to bare wood and are overpowered by the smell of genuine turpentine, you have got pitch pine. If not, you have got the much commoner, and less resistant, Douglas fir, usually sold in this country as "BCP" - "British Columbian Pine". "
I once read an article (perhaps in Wooden Boat) about the meaning of pitch pine. It said pitch pine was essentially cut down by the American Civil War ie 1860's, and what the Americans call yellow longleaf pine but we called pitch pine was widely available up until WW2 and used as boatbuilding timber for planking extensively.
I too have come across people who've claimed their post WW2 boats were built of pitch pine despite the builders adverts stating BC pine or Douglas Fir.
I once read an article (perhaps in Wooden Boat) about the meaning of pitch pine. It said pitch pine was essentially cut down by the American Civil War ie 1860's, and what the Americans call yellow longleaf pine but we called pitch pine was widely available up until WW2 and used as boatbuilding timber for planking extensively.
I too have come across people who've claimed their post WW2 boats were built of pitch pine despite the builders adverts stating BC pine or Douglas Fir.
Keith 66
Well-Known Member
Proper pitch pine is wonderful stuff, you will be lucky to find any today in the Uk.
A friend still has some heavy lumps that came out of a tanning works, It was used to build the vats. The surface is dry & discoloured but plane a 1/4" off & it is perfect, the best stuff has so much resin you cannot put it through a planer as the resin builds up on the feed rollers & garms them up. It is heavy stuff. I would take a boat built out of this over a mahogany boat any day.
My favorite cigar box guitar has a neck made from pitch pine, great tone & doesnt need a truss rod!
A friend still has some heavy lumps that came out of a tanning works, It was used to build the vats. The surface is dry & discoloured but plane a 1/4" off & it is perfect, the best stuff has so much resin you cannot put it through a planer as the resin builds up on the feed rollers & garms them up. It is heavy stuff. I would take a boat built out of this over a mahogany boat any day.
My favorite cigar box guitar has a neck made from pitch pine, great tone & doesnt need a truss rod!
scotty123
Well-Known Member
Mahogany doesn't like standing freshwater anywhere near it, it rots, so wouldn't want it as a hull other than in seawater.
Knobbly
New Member
If you're planning to sail in warmer seas, iroko or teak as they are more resistant to worms. Iroko is a lovely wood and takes International's Woodskin (oil/varnish hybrid) beautifully.