Posted by Jonathan Labaree on September 14, 2004 at 14:42:02 from 207.5.234.19 user JLabaree.
In Reply to: Re: Kon Tiki talk and waterlogged logs, was Re: Swallow and Dreadnought posted by Eric Abraham on September 14, 2004 at 13:45:17:
It takes quite a long time for the types of wood commonly used in boatbuilding to become waterlogged (i.e. get so much water that the wood actually sinks). That's not the same thing, of course, as taking up water and swelling, which many wooden boats rely upon to be watertight.
While varnish does provide a waterproof barrier, it would not hold up for very long under constant contact with water – it’s more to keep out rain and spray. Thus, few boats are varnished below the waterline. Those that are are usually “dry stored” – that is, hoisted out after every use. It is used above the waterline and must be applied in many coats and often reapplied half-way through the season to be effective.
Paint, which is generally used below the waterline as well as above, does not prevent water from soaking into wood. If it did, wooden boats wouldn’t swell and therefore most would leak. There are indeed modern paints that are waterproof, but using them on wood is problematic.
I recently read that Thor Heyerdahl's grandson is among a team planning to recreate his journey on Kon Tiki. So, Eric, you may have a chance to fulfill your childhood dream and sign on!