Survivorman - Building a raft

[spamel]

Just watched the Survivorman episode where our hero, Les, builds a raft. It was a pretty bonk effort but he did say he'd never built one before. What struck me was the raft pretty much sank from the off, and I started thinking back to other rafts I'd seen on TV over the years. I seem to recall a Huckleberry Finn programme from when I was a kid where they had a huge raft made from pretty substantial sized logs which floated nicely.

Thinking on a bit, I wondered if there is any difference to what type of wood you use. Is one more floaty than another, and I suppose seasoned dry wood will float better than green wood. Has anybody got any actual experience in raft building and can they suggest a decent wood that will keep you out of the water? This is purely an interest thing, although if I could live on that Huckleberry Finn raft......!

 

[scoops_uk]

I think the difference is in the amount of wood used, the "Huckleberry Finn" logging rafts were big logs tied to big logs.

Most logs seem to float just level with the surface rather than much above it, so I guess you would need more than one layer (with big logs!) to form a platform above the water surface.

Scoops

 

[sxmolloy]

Hey Scoops, which one of the four people in that pic is you? :tapedshut

 

[spamel]

This is what I thought, logs don't stand too proud of the water, they are usually semi submerged or more. It must be certain woods that float best. Pine is quite a light wood once seasoned, this would surely make a difference to its floatabilty (if that is a word!).

 

[scoops_uk]

Hey Scoops, which one of the four people in that pic is you? :tapedshut

The one with the tilley hat, 2nd from left

 

[BOD]

Never built a raft.

Watched the Kon Tiki expedition DVD and Thor Heyerdahl said he was glad they had listened to the Indians and built the raft from greenwood and not seasoned wood as Western experts told them too or they'd have been in trouble.

 

[JonnyP]

Never built a raft.

Watched the Kon Tiki expedition DVD and Thor Heyerdahl said he was glad they had listened to the Indians and built the raft from greenwood and not seasoned wood as Western experts told them too or they'd have been in trouble.

Yes, I have the book of the expedition, amazing story....

 

[born2roam]

Unfortunately Bamboo doesn't grow everywhere...

I know, I know, it's a grass...not a tree but great rafting material...

Grtz Johan

 

[Porcupine]

why wouldnt reeds be possible? basicly tie a few bundles together and go for it


or is that oversimplified?

 

[spamel]

Not saying reeds aren't possible, I believe the egyptians made boats from reeds bundled together. The point of the thread was to try and establish which wood would be the best to make a raft, or if there is very little difference to them (I suspect there will be one wood ideally suited and much better than the others, but I've yet to see somebodt say so). Also, if seasoned wood makes a difference or not.

Does anybody know for sure?

 

[PJMCBear]

Balsa, although I'm not sure how big a tree this is.

 

[BOD]

Balsa, although I'm not sure how big a tree this is.

Big enough for a raft to cross the Pacific I believe!

 

[Grooveski]

Watched the Kon Tiki expedition DVD.....

Never knew there was such a thing. Many thanks for the heads up - off to find a copy.

 

[weaver]

Look here at the Specific Gravity of certain green and dried woods.

http://www.engineeringtoolbox.com/weigt-wood-d_821.html

Obviously the dry will float higher in the water. But, if the specie of wood is porous it will rapidly absorb water causing it to sink.

The trick is to find the highest Specific Gravity in a dry wood that has closed cells and so will not absorb water.

 

[spamel]

Nice one Weaver! It would seem Willow would be a good wood to use, or alder. Very informative stuff, cheers!

 

[RobertRogers]

I suspect softwoods such as pine and balsam fir will float better than hardwoods like maple and yellow birch. Weight per volume of wood means the differnece.

I live in the United States, your wood species may vary.

 

[chipstick]

I have never seen a raft on TV that seemed to be any good (i.e anything other than 90% submerged). It always seems to me that the reason they never work on TV is because whatever "expert" is building the raft always leaves it only 4 or 5 feet wide and only a single layer of logs. I guess they're a bit lazy because they're only making the thing for TV.

To answer your question, I would think Spruce would be the best natural wood for a raft (after all, they built a plane from the stuff). Most pine would be good. From personal experience I can recommend willow, and I imagine that partially rotted white wood from the forest floor might help to make a good raft if enough is used.

 

[Grooveski]

Watched the Kon Tiki expedition DVD and Thor Heyerdahl said he was glad they had listened to the Indians and built the raft from greenwood and not seasoned wood as Western experts told them too or they'd have been in trouble.

Just watched it, excellent! Have read the book pretty-much annualy since I was a kid. Knew from it that they'd filmed the crossing but hadn't ever thought to look for it.
Enjoyed the narration as well - passages from the book. Didn't cover the full story but accompanied the footage well.

Great to see it in action. That's how to build a raft.