I suspect most center-cockpit boats of this vintage had a similar limitation: where/how to run mechanical bits (exhaust, steering, etc) aft without interfering with the aft living spaces? I have seen some Westsail 42's do a port side-exit amidships for engine exhaust, which can be a simple and easy install giving you the shortest hose run possible (ideal). But I can't do that, given how I designed the engine room, without a big hose looming over your head. I would rather have exhaust discharge aft anyway.
So I came up with a stern discharge solution that involves a Vetus exhaust "gooseneck". With wet exhaust you want the hose to "loop" up to a high point within the boat (the higher the better). This will prevent any following waves from "backfilling" into the exhaust and the engine. Saltwater backing into a diesel engine can kill it quickly unless you remedy it immediately (usually involves removing the engine heads before corrosion has a chance to work). If you have the space, simply looping the exhaust hose up-then-down from a high point is sufficient. But exhaust hose cannot bend enough for that to work in the small space we have.
|Test fit of gooseneck in port-aft quarter.|
|Discharge from gooseneck, down and toward the stern, underneath the aft-berth.|
That is the idea at least.