advice needed on which timber to use for skids on a trailer

[GBC]

I agree with bigjimb, oregon isn't an external grade of timber. I've used it as jin poles etc and it has it's uses but it wouldn't be high on my list for boat skids. The stuff we used was Canadian Skookum.

You've bought kd. Think of it as 'pre shrunk' - it is for use where seasoning and the associated shrinking has been achieved prior to the member being used in internal construction. As you dunk it under water the beams are going to want to reconstitute somewhat. The effects won't be catastrophic, but I'd certainly be giving a little extra clearance on bolt holes etc to give it the chance to do what it will do naturally, without splitting too much.

I'd also entertain strapping or binding the ends to prevent splitting.

C.N. oil is as good a rot preventer as any and I'd be liberal with it. You can get it from the hardware. K.D. generally is raw and not treated with anything.

I personally probably would just go for some slightly larger section cca rougher header.

Tony and the boys at Moxon's have some amazing timbers, but I don't know that I'd bother them (or my bank account) for burmese teak or King billy pine to 'waste' on a boat trailer?

[oldboot]

Oregon or "Douglas Fir" is very popular in wooden boat building because it has one of the highest strength to weight ratios in timber ( as long as it is good stuff).

while all timber shrinks (particularly radialy) as it is dried from green, it will not expand anywhere near as much when it is wetted after proper curing.

Much of oregan's bad press has come from it being used extensivly in the cheapest grades in this country, and it being sold and used very green.

As far as cracking and splitting there are haeps of hardwoods that crack plenty more than oregan.

As far as leaving clearance for bolt holes, ya should do this with any timber.....many of the hardwoods will expand into bolt holes if made neat, and the tannins ( acids that stain) in the hardwoods will considerably accelerate the corrosion of that fastener.

On several ocasions I have had to belt bolts out of hardwood poles because of the above....and on more than one ocasion completely failed to remove bolts because they were so well corroded into a neat hole.

I love hardwood and have a shed full of the stuff.... but on boat skids.....I would be using hoop pine ( not a pine at all) as a preference.........it is far less prone to split, crack and misbehave that most other woods, it has almost no tanin and can be had in decent section clear.
It also has a pretty good strength to weight ratio.

cheers

[timddo]

Just buy a peice of 100x50 length of Fencing grade treated pine rails.

$10.80 i think from bunnings. 4.8 meter length.