On my 26u the engine clamshell are angled downward at about a 60* angle off of horizontal. One is angled forward the other aft. Should I have any concerns about water, let’s say from a large wave, getting into the engine room?
Ed
I should have proofread my question. I’m referring to the clamshell vent angled forward making it easier for water to enter.
FWIW, on both my previous N26C #143 and my current N26U #233, the clamshells were angled down toward aft on both sides.
I think the goal is to have them enough over the vent holes that a wave from either forward, aft or the side would likely deflect around it. I think the biggest risk from which way you orient it would come from whether you usually hose it down from one way or the other. A directed flow of water could easily deflect off the deck in addition to getting channeled upwards.
It’s possible that the different orientations are intended to channel air in from forward facing one and vent it out from the aft facing one.
-- Bob
Thanks for the reply Bob. I’m not particularly concerned but the admiral has been questioning me a couple of times about the forward facing clamshell so I figured I’d better ask around. 
Both mine face aft at a 45 degree angle for the engine and the other for the fan vent.
Facing forward would risk water ingress when sailing….
I don’t have a fan on either of my vents but that’s on the to do list.
One is an intake for the engine, no fan required the other should have a hose from the bilge blower to exhaust possible engine or propane gasket from the bilge. The switch is usually in the lazarette under the engine gauges