Exhaust system on diesel air heater

[tolly]

I am planning to install two diesel heaters on my 50' sail catamaran, and trying to avoid possible mistakes I turn to this forum for advice.

I was thinking, to prevent wind blowing into the exhaust pipe and killing the flame of the burner with all the problems that can come with that, wouldn it then be a good idea to let the exhaust pipe come out through the inside of the hulls, just under the bridgedeck?

At some points there will naturally be water passing by/ flushing on it at that position, but since it is significant lower placed than the burner, it shouldn't negatively effect that...or? I can always put some cover outside, stopping the worst waves.

Is it a problem letting the exhaust fumes go downwards the last say 2 feet of the exhaust tube?

I was also thinking of taking the inlet air from the salon, instead from outside, since if taking it from outside, I will always have to heat colder air. Of course there is a risk that the burner will leak in to the air system, but to me it seemes as a very small risk. Having day and night fans continously operating , together with a gas warning system, should be sufficient when it comes to safety I guess. What's your opinion?