Boat plan Free

Correcting Mistakes II The Usefulness of Square Corners

When we went to put sheets of plywood on the top, er, bottom of the boat hull, they didnt really line up.  WTF?  It seemed unlikely that four sheets of plywood were manufactured not quite square, so we had to look elsewhere.


When we assembled the stringers with the cross beams, we had squared the pieces more or less, but little errors at the quarter inch level really add up over a 20 foot boat.  We hadnt thought to square the boat up as a whole unit.

So now we measured corner-to-corner to find that there was a difference of about and inch and a half.  Not giant, but enough to make the plywood fit funny on top, er, bottom.  We hadnt made a rectangular boat hull, wed made a parallelogram.


That night I had a dream:  We were using a come-along to square up the boat.  Brilliant!  Thanks, subconscious!  So that morning, we grabbed my come-along and screwed big-ass eye bolts into the opposite (long) corners.


My come-along didnt go the distance, so we borrowed a hooked chain from the boat trailer and doubled it up.


We worked for a while to find the route for the chain and the come-along that when tightened wouldnt tear the building form apart.


We then started working my rusty come-along to square the boat.  Kai was working the come-along originally until she realized with horror that one of the two stops that keep the ratchet from violently unratcheting broke off and fell out.  She didnt want to have to explain to people for the rest of her life about that gnarly scar across her forehead so she passed on that job.


So I got to work the come-along.


After a half dozen clicks under tension the boat was approaching square.  Oh wait, too far.  Back off.  Whoops, too little.  More tension.  We played that game back and forth for a while.


Until finally the two corners were within a quarter inch of each other. Once we got the sheeting on the bottom screwed and epoxied down, the boat would stay square.


Next we sheet the bottom of the hull.