Going to be building a garage this summer thinking a 42 would be largest boat we may ever own. How tall are they on a trailer? 10' tall doors ok?
Thanks

Yep, you will be fine with a 10' tall door.
Accordingly, 12' ceiling height (2' taller than door) is fine for standing in the boat, and working in & around it as well as on the deck. (Can't stand on deck, but can wax it.)

Remember, boat plus 7 feet is a good average length for OAL on a trailer. There are some other posts which list variables.
Don't build a bay shorter than 50' deep, period.

Thanks for the info 50' is what I was thinking just have to get it past the city.

My 42 on a an eagle trailer is 46' from coupler to swim plaform. I'm building a 50' long barn now.

If you vacuum the inside with a shop vac like I do, you can attach the cheap black flex hose to 2" PVC, run it up the wall and half way over the top of the boat where you connect a 10' hose to the PVC. this leaves the vac on the floor and you can reach just about anywhere. yea, it takes a liitle creativity and modifying but well worth it

Speedfreek, what a great idea. I have been hauling my huge shopvac in and out of my trailered boat forever! I'm going to try your idea. I'll probably have a much cleaner boat this summer!

Brilliant!