Would you happen to be a member of one or more of the associations that think they represent UK boating? Do you usually attack random strangers like that?
Plastic tubs, not tin, and more than one, and he thinks 20mph is more like it than 2mph with a good wind behind him. His roof is very cluttered - there's a great big metal pole on it for starters, the wires will probably stay there and solar panels.
There are other alternatives, but Alan will be delighted that you bit. He has been sitting under his bridge waiting for the billy goats for a week on this one.