I am looking at getting a portable garage/canopy to cover the boat for the winter so I can work on it. What is the better type of roof that will let the snow fall off it, the kind that has a peak or the kind that is a round dome?

I would go with the one that has a peak. You are going to have to shovel the snow off of it anyways. I know that some of them have a snow load rating but don't count on it.

A buddy of mine had a Cover-It that I he bought and erected in 2000. I bought it from him in 2002, and sold it a year later to another guy. It was sold once more as well. Last time I checked last year, it was still standing. (Never moved, just new owners in same storage lot.)

This was in Northern Virginia, and while it did not get repeated snowfall, it held up well to the dumpings we got. It was a round top.

Pics below are all I have, but you can see how the snow accumulated on the one next to mine. A strong push with a push broom from the inside, and whatever was on top would slide down. This snowfall was 6-8 inches of heavy wet stuff.

I had a round top in MA for ten years and never had a problem. I would get the vents for the doors to keep moisture down they are so tight it can keep a lot of moisture in. Be sure it is held down well, I would take the ropes from the boat and tie it off on both sides just to be sure.

I have an "A" roof style in VA. We get some wet snow but not in huge volumes. I would rather have the rounded roof style if possible. Get the Galvanized pipes (not powder coated) in 2.38 thickness (not 1.98). The material comes in 7 oz, 8 oz, 10oz, and occasionally 12 oz. Obviously the thicker the better but it costs more. If you get alot of wind make sure you get good secure anchors too.
For moisture...these things draw an unbelievable amount of moisture from the ground.....in VA's humid climate it can nearly rain inside the thing. Make sure you lay down a layer of plastic on the ground and it will nearly eliminate that problem.

what he said!!!!!!!

Good idea on the plastic as well. I bought some 10mil industrial poly from a construction supply place. Its almost as thick as a swimming pool liner.