Timber Raft

[andyBruce]

Hello,

I'm quite a fan of traditional, backwoods, or "primative" skills. One of the things that I've been looking at is traditional timber rafts (straight tree trunks lashed together) and was wondering if anybody could answer this for me.....


How many average sized mature pine trees would it take to float an adult?

I know there are alot of variables, and I wouldn't be likely to keep my socks dry, but, any ideas would be welcome!

Thanks everybody.

 

[tiger stacker]

Have a look at the Kon-Tiki Raft 9 balsa tree trunks enabed 5 men to sail across the Pacific in 1947.

 

[Toddy]

What do you mean by average sized ?

Nowadays the FC average Scots pine felling at 57 years, but the ones that are left to grow and were cut for log boats are nearly a metre in diametre.

To float a human you need only about five pounds of 'lift' since the body is naturally buoyant.

Don't know if that helps any though

cheers,
Toddy

 

[Retired Member southey]

id say from playing with washed up logs around 12 foot long, you'd only need one to float but at least two to be stable and able to stand on and paddle if you wanted, though these were log time cut logs so were pretty dry, around one foot thick,

 

[andyBruce]

I'm just playing with ideas and thoughts at the moment! I think the use of the word average was probably short sighted on my behalf!
I think I'd be looking at trunks around 2' in diameter, or there abouts!

As always, I'm very impressed by the speed which you guys respond, and the info you have stored away!

Thank you!

 

[forrestdweller]

Have a look at the Kon-Tiki Raft 9 balsa tree trunks enabed 5 men to sail across the Pacific in 1947.

small correction: they were six crew members- five norwegian and one swedish

 

[andyBruce]

Well, after some extensive research, it turns out that its pretty difficult to source timber for rafting. the forestry commission around burrator resevoir have some issues with tree disease and so are very choosy about what is allowed in the water (understandably!)

With some help, i managed to find some timber although it was unseasoned and only 8' long, we decided that 11 of these should be enough.............................. Possibly not entirely accurate!

after loading the trailer with the timber (each log weighing around 45kg) we headed to a lake to try it out!
The raft held together very well with square lashing and floated well, untill i got on it, it floated just about on the water level but with any shift in weight the raft submerged slightly!

The end result was an awesome looking raft with some mild floatation issues! The brief was that the raft needed to float 2 people across the reservoir and be bark covered timber, so......

I built 2 rafts! one from seasoned timber that was slightly smaller than the traditional looking raft. The seasoned raft sat under the non seasoned and gave enough bouyancy to float the two paddlers across the water, and not see the seasoned wood!


all in all, Longer timber would have been much more appropriate, and seasoned timber would have been wonderful, if you ever get the chance to get hold of seasoned timber, (we had larch) around 12' long and 6' diameter, and want to build a traditional style timber raft, buy it all! these rafts are excellent to paddle, fun to build and very satisfying.
however the timber is pretty heavy!

I do have some pictures of the finished raft and will try to work out how to upload them!

Having built this type of raft now, i would definately build another given the chance, and if anybody fancies trying out this type of raft, in the southwest, I can help!

Andy

 

[spandit]

I used to love the raft building at a gravel pit in South Cerney near Cirencester. It was virtually guaranteed that you'd end up in the water with a load of loosely lashed barrels & timber