Type of wood

[Guest]

I am thinking of getting a timber hulled boat - probably a motor cruiser. I am new to this and have been doing a fair bit of reading around. Most writers warn of the problems of using mahogany for the hull on boats that are to be mainly used in fresh water. However a number of well respected boat makers seem to have used this wood in their crusiers, e.g. William Osbourne. Should I steer clear of these or are they OK?

 

[Guest]

Joe, I don't expect you'd have any problems whatever. Mahogany is not a timber we use here, though, so there's a good deal I don't know about it. You'll get the best answer to this question by posting it on the WoodenBoat Forum, at --

http://media5.hypernet.com/cgi-bin/UBB/Ultimate.cgi?action=intro

Diferent people will tell you differently, but I'm very clear that if you're using a boat in freshwater and she lets in more than just a cupful or so, then you should put a handful or two of salt in the bilges to help stave off rot.

For ingress of only a very little water, it's probably best to hold the salt and to use a sponge dry the planking right out instead. This is because salt is hygroscopic and will attract moisture from the atmosphere, thus keeping the bilges constantly damp -- even when "dry."

mikefield@woodenboatfittings.com

 

[Mirelle]

I agree with Mike - post the question on the Woodeboat magazine forum (and subscribe to the magazine, incidentally, it is a complement to, rather than a competitor of, Classic Boat).

However, I would be a bit careful about mahogany planking in fresh water - in the case of a post-War boat, very careful indeed, as much more African mahogany was used then, and this is considered trickier stuff. The pecking order (best at top) is

Honduras
Philippine
African

Part of the problem is that during the period 1945-65, approximately, it was difficult to get good timber and this forced some yards into using "experiemental" materials.

It is worth noting that James Silver did not use mahogany, so far as I know the firm used only teak and pitch pine for plankng - both of which are quite safe.

 

[Guest]

Thanks for the info. I'm actually thinking of an Osborne Kestrel, circa 1960 wiht double skin mahogany. Sounds like it might be a problem although the seller has told me it spent many of its first 15 years in sea water and "the hull is wel pickled". Ay views on this?

 

[Mirelle]

I would be rather careful. The "pickling" argument is really nonsense, as the salt migrates out fast in fresh water (the osmosis principle) so there is nothing to that.

There is a bit of confusion over this, as some woods, eg. most famously, English Oak, either rot in the first few years (due, usually, to incorporation of sapwood) or do not rot at all. This gets confused with talk about pickling. But a boat built of mahogany in 1960 is most likely African mahogany.

If you do decide to go ahead, this is a case where you REALLY need a surveyor familiar with wooden boats. Meanwhile, have a careful look yourself and in particular look around the fastenings; Lloyds Rules were changed soon after
this date because of alarming cases of rot around fastenings in African mahogany.

Double skin is deservedly unpopular; if you think about how much outer skin you need to remove to deal with a single strake on the inner skin and you will see why at once!

A pre-War boat is likely to be carvel built of better quality materials and is therefore much easier to look after. There are some lovely ones, at quite reasonable prices.