Talador,

  Thanks for the tip on ventilation. 

  The dory's well will have an open top, with the top of the motor completely exposed, so that probably won't be an issue.  However, an outboard in a well in a proa would need a ventilation solution.  I'll have to ask the guys over at Presto what they do about it, and perhaps see if I can convince someone to run a speed test with the top hatch open versus shut.

  The dory is scheduled to be finished in the fall.  Of course, it's been scheduled for launch each of the last three Septembers, so I'm not going to get adamant about it.  We're finishing up a house build project right now and I imagine that's going to eat into my free boatbuilding time.  Work has a way of interfering with it, to.

  But I can't wait to take on some three-foot seas with that stead rumble of the yanmar diesel outboard.  /Much/ cooler than trying to do the same thing on a planing skiff.

        - Mike

 

Mike - " I don't yet know how much smoke will make it up from the underwater exhaust into the well."

Very neat about the dory.

About an engine in a confined area, when doing dynometer engines tests in a well ventilated engine room we inadvertently discovered that opening or closing the door could have a huge affect on the brake horsepower and the temperature of the engine for the test.  We ended up taking out a whole wall for ventilation purposes and made ambient temperature, pressure and humidity corrections too.

Double any ventilation openings for an engine space, and then double them again.  All an engine is is a pump and any unnecessary restrictions just hurts performance, a lot.

Talador