Tuesday, March 15, 2011

Wood Density

My fascination with the weight of the kayak I’m building is growing with my surprise at just how light in weight the hull is. I thought I’d do a quick check on a couple of samples of Paulownia and Cedar.

For the wood I’ve bought it works out that Cedar is about 0.40g/cm3 (about 17 lbs/ft3), and the Paulownia is about 0.27g/cm3 (about 25lbs/ft3). So the Paulownia is 2/3rds the density of the Cedar!

Now that has me thinking – I’m mostly building the deck in Cedar – the extra wood weight plus the coming/deck deckplates etc – hmmm, will it be tippy without me in it? I reckon from looking at it that the deck is about 2/3rds the size of the hull so it might will be balanced at about the same weight top half and bottom half!


Paul Squire said...

The weights you're achieving are impressive! I'm excited because I'm going to use Paulowina for my Hunter. By my calculations your Cedar deck will be 1.6kg heavier than a Paulowina one. For this reason I think I'll build my entire boat from Paulowina. Returning to yours, thats about the equivalent of a spare paddle, a drink bottle & a sandwich strapped to the deck. I reckon it'll stay upside up without you in it. I'm looking forward to seeing the other tricks you must have deployed to achieve such low weight. Cheers, Paul

Bohdan Szymanik said...

I think the other aspect that's keeping the weight down is the high density 170g fibreglass. The last boat I made used 200g fibreglass - this seemed to soak up a lot more epoxy and seemed a lot more solid.