Merbau for planking?

[woodenboat]

Who may know?
Is merbau (Kwila ?) suitable for planking a 38 foot displacement
motor/sailer (slow). Environmental considerations aside, what are
the the pros and cons for using this timber for this task-planking !
Thankyou in advance for your advice/experience.

[D'ARTOIS]

Merbau = Ironwood; Class II, 550 kg m3 is generally used in Indonesia as main structural hull material. It is strong, rot resistant and entirely useful and acceptable in the traditional tropical way of shipbuilding.

The negative aspects are: Bonding characteristics are generally not good;
Glueing is similar or worth to teak; painting and varnishing are void, useless.
In sunny climates the varnish burns in no time away.
All those negative aspects are caused by the internal secretian of the woods liquids, called "bleeding".
For modern purposes and applications: think about it twice but if you can live with the negative aspects it is in technical sense a good usuable wood.

[artemis]

And if you're doing repair work with a boat in the water, don't drop a plank - it doesn't float!

[woodenboat]

Thankyou D'ARTOIS for that information.
You've confirmed in my own mind a number of issues.
Yes, I'm very aware of that prolonged "greasy" bleeding of merbau, which in fact is its preservative and rot resistant characteristic.
I suppose that epoxy resin will have the same adhesion problems that paints and glues would have. Are the traditional tropical boats left in a 'natural" state? Also, is there any advantage to be significantly gained by ageing the timber to a "silver/grey-coloured" state?
Do you know of any written/web info that discusses merbau and boatbuilding?
Thankyou again for your time and consideration. Regards

[D'ARTOIS]

Wooden Boat, I don't. It just depends on availability. The Buganese boatbuilders from Indinesia (from Celebes) are using it on teak frames, for ages. And why not? It a native wood, easily available and offers good enough qualities for their purposes.
I have some Buginese designs, will show you a picture or so. Then you have some idea. I think you can paint it by using Alkyd based paints, do not know if hey are still allowed environmentally.
I have some experience with merbau and it is good in a salty and humid environment, I used to live on the sea shore and my door- and windowframes were made of either merbau or meranti. Meranti is more a Phillipine/Thai wood, most generally called the Asian forest-oak.

[PAR]

Seems to be quite a heavy stock for planking. I'd think it better suited for structural members like keels, frames and floors. Letting the surface deteriorate under the effects of UV (allowing it to go gray) isn't a good idea. The material at the surface (the gray stuff) has lost most of what we desire in the lumber in the first place. It may be forced to take on a coating of paint or adhesive, but there would be a few extra steps involved. Heating the well cleaned (chemically) lumber before adhesive application (especially epoxy) would help a great deal in the stick-um ability of the goo. This may prove difficult on long sections of planking stock, but does work great on parts small enough to fit in an oven.

[D'ARTOIS]

Paul, it is not so heavy, specific gravity is 5,5 = about the same as Honduras Mahogany. Problem is that timber from S-W Asia comes in a number of varieties and those woods are looking very similar - here and there different colours but grainwise they are quite similar. The guy who posted this question lives in Australia; probably the deforestation of the famous Kauri has brought the Merbau to Oz.
You have all the topwoods for planking next door: Abarco, Mahogany, - the heavy pines, lolbolly, slash - the ceders, Port Orford, Oregon, Larch - name it.

About the graying you are right. I have no particular knowledge of treating Merbau. It is in Holland not considered as a boatbuilding material.
The only thing I have ever heard is that the best woods of the US go to Japan for building houses, in particular Sitka Spruce.

[PAR]

Brien, I thought Ironwood was a lot denser then that, didn't bother to look it up of course. I would think there would be a difference in properties from one growth area to the next (soil mineral and chemical draw up and all) Is it farmed or natural stands?

[D'ARTOIS]

Paul, that is very well possible. There are varieties, but the weight does not exceed 650 kg / m3; it remains within the scale of the Afrcan hardwoods and the mahoganies. Meranti (lauan) is softer and a bit less in quality than Ironwood, that is much harder. Ironwood is found in the Indonesian Archepelago and Papua New Guinee.
Commercial lengths are up to 500 cm.