In the process of turning my hunks of plywood into something that is starting to look like a boat, I wanted do my best to align the major parts: keel and stem, hull bottom, deck.
The keel was already on the cart, so I set the front end of the hull bottom into the notch in the stem where it goes. Then I suspended the deck from the garage rafters, positioning the cart beneath.
I dug out my (fairly old) laser level and put it to work.
This photo shows that the deck, hull bottom, and center keel lamination are nicely aligned.