Generic Warm air Heaters Tale .A story so Far.

[vyv_cox]

Transom is best, especially if you are a sociable cove and not likely to have a melt down if somebody has the temerity to moor along side you at some point in your boating life.
Less likely the noise will annoy your neighbour or scorch his gelcoat, it will not set fire to or melt holes in your fenders .

I think the reason transom mounting is recommended is that it is less likely to be flooded when sailing. On my motor sailer, very unlikely to heel due to sailing loads, I mounted it high in the topsides, then forgot and burnt a hole through the winter cover.