Artimis

If needs, must

No, it's not a wet exhaust. Vertical is impossible, it must exit to port or starboard horizontally. If to sbd, the pipe will pass v close to weed hatch. If to port, which is shorter route, I have to blow another hole in the hull

Another question Assuming the hull exit is as high as reasonably possible above waterline, common sense suggests a swan neck in the pipe to prevent water ingress, so how does the swan neck fit below deck?

Nope, cant find anything relating to exhaust pipes

To clarify....the whole of the aft end, the transom is 2 big fuel tanks, so the exhaust either has to traverse the width of the boat to either port or starboard, but the weed hatch is the nearest place by far, and happens to be very close by. blowing a hole isnt a problem with plasma, i just hoped to cut down on the length of tube which would go straight from the manifold, 3 feet at the most, direct into the weed hatch

Is there any BSS reason why the exhaust cannot exit the boat via the weed hatch, rather than blow another hole in the hull side? Obviously the weed hatch lid will be gas and water tight, and the engine wont be running when its open for clearance. Also, does the exhaust tube need to have a swan neck inside the engine compartment to prevent water running back to the engine? What do the latest regs stipulate about a silencer?

Look at them all and find one that suits your needs. Its the flat back and mounting points that are important

Its up to you to crunch the numbers but I would go for a larger genny, up to 30kva, purpose made in a sound proof container, one thats designed for many thousands of hours use. Register it and install so you can couple up to the grid and export power and get paid for it. In return, you get the power you want, the Feed in Tariff (FIT) covers your costs, you have heat back from it as well. Sounds expensive?, NO google and learn. Meanwhile, forget PV and windy gens. You need exceptional location and investment to cover your needs

My folks were on the bandwagon in the early 80s to breed and farm crawfish. The dangers of escaped and feral foreigners wasnt understood and thousands were released into ponds and reservoirs. It was all part of farm diversification, encouraged by MAFF, the predecessor of DEFRA Females with eggs have to be kept in cages which allow the young to escape once hatched so mum doesnt eat them. Adults can give you a very nasty nip and are agressive.

Get round the scrap yards and pick one up for £3 like I did. it sure beats £40