which mahogany?

O

ossygobbin

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lancashire, england
www.kestrel22.com
hi,this is a request for info. please could anyone advise regarding which type of mahogany to use in the rebuilding of a centercase. what is the difference between african and brazilian mahogany in terms of boatbuilding.(apart from the price) which is the better suited to my job in hand. all help gratefully received.

ossygobbin
 
Hi,
Unless your boat is a real classic deserving the use of very rare tropical hardwoods, I would be inclined to use the high quality Scandinavian plywoods made to marine grade from sustainable softwoods. Do not be put off by the word "softwood" when appplied to wood from these latitudes. A friend of mine become a caretaker for a 100 year old school in southern Sweden. The building was made entirely of windows all held in softwood frames and all !00 years old. It took him ten years to cover every piece of wood in the building, but he found no rot at all. It had been maintained, but it was very old.
I have had limited experience of the plywoods of which I speak and they 'work' very much the same as any other ply and in many ways far more easily than solid wood.
I hope this helps and if you really need to do it in mahogany try to find a reclaimed piece of Brazillian similar in age to the boat. Helps the 'soul'.
Regards,
Nicki
 
I would second all of that, especially the use of recycled timber. I would have thought that the end posts should be made of a timber like teak that the little wood-chewing critters don't like; the sides of aforementioned plywood, and the case-logs of a nice hardwood like elm. I wouldn't be looking at mahogany at all.
Peter.
 
A less \"PC\" response

In a nutshell: the Latin American mahoganies are the real stuff, but the African mahoganies are related. The so-called Philippine mahoganies are not, and they don't come from the Phlippines either, as the Philippines was logged out years ago.

It comes from Indonesia now and is usually illegally logged. Some of this timber is good but most of it is rubbish and not durable at all - fit only for shuttering plywood.

There is a specific problem in relation to the resistance to electrolytic damage of African mahoganies, which was responsible for the early demise of many post-WW2 British built wooden boats. Case in point - Eric Hiscock's Wanderer III was intended to be planked with African mahogany, but ended up with iroko instead. As her present owner says in a very good article on repairs in the last edition but one of the American magazine "Woodenboat", "If mahogany had been used, she would not be here now." This problem is now well known and is discussed in Lloyd's yacht Rules.

It follows that unless weight is critical I would suggest the use of iroko, which is still available ar reasonable prices and is considerably more durable.

If weight is critical and cost is less important, use Brazilian mahogany.

Now, getting on to the PC stuff. The durability of softwoods in the Scandinavian climate is a very poor guide to what happens elsewhere. Taking an admittedly extreme case,; I have seen tree trunks washed up on raised beaches in Spitzbergen where the beach is now 300 feet above the sea, so the trees have been there for centuries, and I have stepped over the remains of a wooden hut erected by a British Polar expedition in the 1820's. Smashed by the weight of snow but the timber was fine. In the UK nothing would have been left of either.

The impact on the world's rain forests of recreational boatbuilding is microscopic. Since China banned domestic logging in the late 1990's due to soil erosion and flooding the rate of forest destruction in Indonesia and Latin America has increased hand over fist. Don't worry about a centreboard case - think about the flat pack furniture bought by all and sundry - where do people imagine that this comes from? the timber is shipped to China, made into the tat we buy and shipped to superstores in the UK, by British companies.

A little common sense, please!
 
Taking this further...

...just to store in my memory, which is hungry for timber-lore...

Where do we stand with Teak? I have some recollection of Crystal's Teak being Burmese, and the Mahogany (all internal) Brazillian. For the interior remodelling, I think reclaimed Latin American Mahogany will be more than adequate, if one can find it - I'm more concerned about the availability of significant amounts of Teak. If, God forbid, we stove in a few planks, what then?

/<
 
Re: A less \"PC\" response

Hi there
You don't say which part of the centre case you wish to replace. Is it all of it and the exiisting one is solid timber or has it got solid timber ends and top with plywood sides or cheeks?
If it has to be solid real mahogany then use that, it is classed as durable whereas African mahogany is only moderately durable. Brazilian mahogany is very expensive these days but its colour and working properties are first class. If colour is not so important then use iroko. It is even more durable than Brazilian mahogany but more difficult to work. I posted a reply a week or so ago about timber merchants who deal with mahogany but if you wish to find suppliers please contact me.

Martin Whitworth
 
Re: A less \"PC\" response

Most timber yards stock new grown mahogany but its not a patch on brazilian , your best bet is to go to homebase and buy garden furnature and reuse that . They seem to not bother about the whole rain forest issue . I have an old door frame out of the poppy factory in Richmond thats around 4"x3" i can mill it to what you need for a few beers with forbsie and i at our Twickenham pontoon .
 
Well, having done just that...

You write out a suitably large cheque, which is one reason why you need to keep an eye on your insured value and why underwriters don't welcome wooden boats with open arms even when they are in perfect order.

Indeed, Mirelle's rudder stock has been iroko since 1989 when the October 87 damage was repaired. Bits of the old, broken, Burma Teak rudder stock are still in the yard's stockpile!
 
Recycled Mahogany.

I have just helped a friend who bought a Mahogany door from our local rubbish tip. It was old but absolutely sound and he picked it up for £20. He reused it as a door but the bits we cut off grace parts of both his and my boat. What country it came from I know not but it was very good to work with and matched the bits we wanted.
 
Re: A less \"PC\" response

Mirelle, I agree with all that you say. The indonesian "hardwood" used to make the Chinese built rubbish we buy is one of my main hobby horses. I think I am roughly correct in saying that in 2001 the Indonesian government authorised the extraction of 25,000 cubic metres and the estimated extraction was in fact 1.5 million cubic metres. I say estimated because it is very hard to to track what is after all an illegal trade.
My thing with the Scandinavian ply is that in the case of a dinghy centreboard for example, the amount of time it is likely to be immersed in water is quite possibly very little. In the case of a centreboard yacht permantly moored afloat it obviously becomes far more critical. I accept that I may have been a little ocer PC and as such find myself boring. Apologies for that.
On the subject of teak there is now virtually no old growth timber being extracted as it has all been used, thus everything is plantation grown and relatively Ok. They even remove it from the forest with elephants to cut down on damage to the flora and fauna. It is a shame that everything is now so contentious and the big sheds selling their cheap wares really do in my opinion carry the burdon of responsibly as you suggest Mirelle, and boatbulding carries far less responsibility. Just a quick illustrative case of the appalling use of these woods: I was given a hardwood garden table (said teak on the box but definitly was not) and the fastenings were so rubbish that I had to replace them before the wood had even changed colour. An insult to both the wood and the purchaser.
Regards,
Nicki
 
Well said!

Nicki,

Thanks, and I am also in complete agreement. You are also quite right about the dinghy centreboard case vs keel boat c/b case, and I should not have taken such a dogmatic position.

I am guilty of recommending iroko, which I strongly suspect is not plantation grown - Ongolo posted some first hand observations on West African forestry here some time ago, and that was one of the points he made.

Your figures on Indonesian logging do not surprise me. I suspect that Kalimantan and Irian Jaya are suffering particularly badly. I also suspect that Latin America is no better.
 
Re: Well said!

There's still some old stock out there. One of my projects is a 1935 'B' Class sailing canoe made of mahogany which is very sound, lovely and dense and rock hard. At some point she's been dropped on a trailer and two holes punched in the bottom so some replacement timber was needed

A phone call to a timber supplier sourced a 13' * 13" * 3" Hondourous plank from Stranraer that had been in a yard for over 50 years and was shipped down to Devon in two days.

There is old timber around but be prepared to pay for it, but compared to the modern stuff it's in a different class.
 
\"B\" class canoe

What an interesting boat!

She must be a very late one indeed, to have been built in 1935, because Uffa Fox and Roger de Quincey had won the Canoe Championship of America in 1933 with "Valiant" and "East Anglian" and the International Canoe Rule had already been drawn up.

My late father's first boat was "Bubble", RCC B class, designed by Linton Hope - the drawings are in Hope's edition of Dixon Kemp.
 
Re: \"B\" class canoe

Ahhh, just checked and the date is wrong.

She was built in 1926, but was registered as an International Canoe in 1935 so was the last IC without a sliding seat (I knew there was a 1935 in there!).

She's a Sven Thorrel design built by Nunn Bros, used to be owned by the late Barry Bucknell and can be seen at www.pegasus18.com/zenith.html
 
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