Prefab steel buildings

How guys

I took the cover of the boat today and found it was full of water

Long story short, I think it would be wise to put up a car port to keep it under during the winter

I'm thinking of going with a place like www.directmetalbuildings.com

Now, this is where it gets tricky

i park the boat next to the downstairs garage door, which is in between 2 small retaining walls, which both have different heights (and neither one extends out far enough

the span will need to be about 24X24


does this sound doable?

any experience with this kind of project?

(all i need is a roof to keep the snow and rain out of the boat)