Louvered breather direction

[sstone]

Which direction should the breather vents on either side of the engine compartment face? It makes sense for them to open aftward, as it would keep splash and/or rain from entering, but would it create air pressure/flow problems at higher speeds (around 50-60 mph)? Or am I way over thinking this?

 

[smokeonthewater]

Re: Louvered breather direction

answer: it depends....

Some boats have an intake forward and exhaust rear... some have intake and exhaust behind same grill and some have all exhaust with intake in deck.

 

[tazrig]

Re: Louvered breather direction

I have a 23' Formula. I have one set of vents facing forward on each side for inhaling and 2 vents on the stern for exhaust. These pics were taken at the beginning of the restoration project but you get the idea. I've never had a problem with water intrusion with the forward facing ones as there are inner baffles that lead straight to the blower hose and into the bilge so nothing lands on the motors if any goes in at all.

 

[Alwhite00]

Re: Louvered breather direction

intake forward, exhaust to the aft. (on my old Sea Ray)

LK

 

[Another retired guy]

Re: Louvered breather direction

intake forward, exhaust to the aft. (on my old Sea Ray

LK

^^ X2. Same on my old '88 Cadorette

 

[sstone]

Re: Louvered breather direction

I can't add pictures yet as they're not on my computer. But it's just a 16"x2 1/8" hole on either side of engine compartment, no hoses or baffles or anything, save for the blower hose up against a portion of one. And no vents on the aft of the boat. I guess I'll see what works and looks best when I have it out next

 

[mxcobra]

Re: Louvered breather direction

If you are talking about the bilge vents, for adding oxygen to the engine compartnt for combunstion.
One facing foward so when you are underway, fresh oxygen is forced into the engine compartment.
the secound set of vent faces to the back and has the blower hooked up to them so you can suck out gasfumes before you start engine so you dont blow up

 

[tpenfield]

Re: Louvered breather direction

I *think* the 'standard' is port side takes in air . . . starboard side exhausts air. So the louvers should be faced accordingly on each side.

 

[H20Rat]

Re: Louvered breather direction

It really doesn't matter, there is no 'correct' way... Obviously at slow speeds there is no wind to push in, you are relying on the blower for ventilation. (although I'd rather have the exhaust pointed back, intake doesn't matter) Once you are running at speed, intake direction makes zero difference. Having the intake face backwards will NOT starve the engine for air in any way, and you aren't getting any ram air effect either, there is more than enough turbulence around a boat to create a pretty big boundary layer.

On my boat the intake/exhaust are both shielded by pockets in engine hatch cover. They are completely out of the airstream. If anything, they end up both pointing backwards after you take into account the pocket shape on the hatch cover.