To set the record straight on canopies and bimini tops I refer you to any picture of a steam launch, a bow rider or a chesapeake deadrise workboat. Any of these would have a lightweight aluminum frame or a lightweight douglas fir frame. The weight is usually under 50 pounds. The canvas covering weighs about 10 pounds.
My boat Lola as an America Cat had a 75 pound aluminum mast standing 25' plus into the air. When the 20 pound sail is set the material is vertical to the wind and creates the windage that allows for laminar flow of air and forward motion of the boat.
In contrast, the horizontal application of a canopy top is in line with the wind direction( which is also horizontal most of the time). I have read posts where people express concern that a good breeze could flip a powerboat or lift it into the air. When you are on a boat with any type of canopy, you do not consider that the top might be unbalanced because you realize you are in a boat that weighs a couple of thousand pounds and that the center of effort is below the waterline and that stability is not really affected in the least.
My goal with Lola before she was turned into a project boat by Sandy was an open launch with canopy top. It was to have an aluminum frame with the striped surrey top like the launches of the 19th century. I didn't invent the idea, I got the idea after seeing a beautiful Herreshoff electric launch a few years back.
Now that I'm rebuilding Lola in my shop, upside down with the deck off and the liner removed. The layout and drive system are going to be unique to the hull type and will be installing a surrey top with douglas fir frames and bronze flanges and fittings. It will look more traditional than the boat above, but will be no more dangerous or top heavy than any boat with a top that you se on the water any day of the week.
As far as being top heavy and having a lot of windage that can adversely affect navigation, I refer you to the photo's Joe has posted of a blue launch with a full cabin enclosure. I believe a boat like that has lost a good deal of initial stability with the height of the cabin and had increased the windage to the point of being difficult to operate in any decent cross wind. Is the boat pretty? yes. Is it stable? I don't think so.
