Dry run on boat levelling

I have had a nagging worry all along that my boat would be out-of-square to the point where I would not be able to install the beam mounts properly. Although I am not ready for these just yet, I decided to do a test run and see just how bad (or good) things really were.

The most accurate gunwale markings I have left are on the beam bulkheads, so I cut out enough of a hole so that I could screw or clamp a small piece of straight wood to each bulkhead. The wood is fixed so that it is even with the gunwale marking. Then I hung tape measures down from each piece of wood. This was so that I could aim a laser level (belonging to my neighbor Sean - thanks for letting me borrow this again) at each tape measure and get an accurate height reading on the gunwale mark at each beam bulkhead. Other builder have done similar things. I aimed the level at a point on the tape measures about 26" below the actual gunwale line; that way the level can "see" the tape measure at all four points.

Here's a rough sketch of the method, excuse the sloppy freehand drawing: Here's a tape measure hanging down; after awhile I scrounged for every tape measure we had in the house so I didn't have to keep moving it around:

The initial readings were actually very very close. When I made my boat cradles, I designed them so that the boat would naturally sit as close to gunwale level as I could get it. The measurements showed all four points within 1.5". Not too bad!

I used an automotive bottle jack to adjust the corners:

Then I'd screw some extra supports to the strong back to hold the cradle at the new position...

...and remove the jack. Yeah I have a big cleanup job under the strongback someday.

I couldn't get all four corners level after 1/2 day of fiddling with it, and sent mail to the F22 builders group on google asking how close the level needs to be. Ian himself replied offline and told me to check sheet 49 where he talks about this. Darn - hate to waste people's time when the answer is in the manual.

I did figure out that one problem was due to the strongback or the cradles "settling" after I'd remove the jack. After that, I was able to get three corners level and the fourth out by only 1/16". According to Ian and the plans this is plenty good enough. Now I'm no longer worried about my lopsided boat and am looking forward to starting the beam mount installs (but have a lot of work left to do before I get there).