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Blocking..... again.

Posted: Tue Sep 15, 2009 8:46 am
by Terry
Hey Rob,
Remember this?
viewtopic.php?f=2&t=78&p=272#p278

Can you give me a description of how you built your blocks/cribs?
Size, how did you connect them, etc.

I was thinking about a 2 foot square of 4x4's, with a threaded rod to connect. Maybe build the outside up with 2x4's to compensate for the hull coming up to the chines.

--
Terry Robb
Mastercard III
http://www.alcanboats.com/mastercard_iii.htm

Re: Blocking..... again.

Posted: Thu Sep 17, 2009 8:50 am
by Rob
Hi Terry:

My blocking is made up of 16" long 4x4s, with each layer screwed to to the previous one with 4" screws. These screws were driven in to the depth of the power bit, so are countersunk about 2". This seems a little "light", but I have been using the same blocks for 15 years and I haul out in a windy location. The top 4x4 (and sometimes a little additional shimming) is loose and is placed as close to the centreline of the main block as possible. This moveable block is aligned with the chine and allows the hull to clear the main block. It is important to have a piece of plywood right against the chine, as the chine will split timber aligned with it.

See http://www.alcanboats.com/dry_land_storage.htm

And . . . David makes a good point about not carrying weight on the keel (at least of an Alwest). I have to rethink my plan for this. The Alcans seem to have more internal structure supporting the keel because I have often seen them blocked at the keel. Although . . . . the Alcan blueprint included by David in the last discussion does not show this ???

Rob