On our power boat Beta 60 instalation point X is 8" above the water line is this considerd to close? and the minium should in fact be no less than 12" which is where they show the Anti syphon valve in the manual. Better to be safe than sorry I know.
Welcome to the forum. Without knowing how the whole exhaust system is run it is impossible to comment. Will it be possible for you to make a good drawing and scan it? If I can see the whole layout I should be able to provide some intelligent answers. This forum will accept a jpeg but not a pdf.
