I am building a garage to someday house something like a 26' Sonic Prowler on a trailer and was wondering if a 9' door would be high enough. I do not know where to look for o/a height on a trailer for certain boats. Thanks for your help.

A 26' Sonic will fit under a 9' door in most cases. A lot depends on the trailer and the grade.

Play it safe, go with 10'. You are always going to want a bigger boat.

A 10' door requires a 12' ceiling height for most door applications. You do not want to try and mess around on the boat, in less than 12' period.

If you ever need more than a 10' door height, there are slim-line door applications that can roll up into the rafters, and get you higher than 10' door height, maybe 11'+.

My 32 AT fits under a 9' tall door with no problem. Make sure you make it at least a 10' wide door.
Build it way bigger than you think you will ever need, because eventually you will need the space. i wish mine was 10' longer and 4' wider and I only built the house 3 years ago.

Go bigger than you think you need, and as big as you can afford. You will NEVER have enough room.

Get a roll up door not a garage door!

Thanks for your suggestions. My ceiling is going to be 11'6" and I planned on a 10' wide door. I am in a residential area on less than an acre so, the higher I go, the less chance of getting the townspeople to O.K. it. I'm just glad to hear that it could be possible with a 9" door. Here is another question for ya, is there that much difference in height between a 26' Sonic and say a 33' which would be the longest I could fit? I know the 26' has a pretty deep transom.

My 32 AT sits about 6" higher on the trailer than my 28 Pantera did. A lot will depend on the which trailer and which boat, but most should fit.

my door is 9' height, width is 12' 10 wood be tight. I have a 14x30x10 tent garage, I am making a fence around it 16w x 30l x 14h and use the tg top as a roof its going to be post and beam all bolted , so its a fence not barn phuck the town, I asked if I could build a fence around my boat since my drive and parts were stolen in march ,they said there was no law on fence height. I am using 6''x 6''x 12' beams 2'' x 10'' x16s for the top braces and it looks like 16' x1'' x6'' deck sides it should cost around 2500 in a few yrs I will put a roof on it thats why the 10''x2''x16s to reinforce plus locks and alarm put the new opening will be 14', some times its hard backing in with the 12' opening, I have to come in on a angle not big just a pain. so go 12' if you can for w, and I can stand in my boat with the 10h there is now. art

I get my 28 Powerquest in my 8' high garage door, just barely.