Engine air intake snorkel above the PH?

I've seen some commercial boats with an engine air intake snorkels above the pilothouse. One guy I watch on youtube bought a commercial boat to use for a hobby business and it has one. I thought these were just simple engine room air intakes, but they are piped directly into the air filter housing. This makes the air intake a sealed duct.



The only reasons I could come up with for this is 1)cooler intake air for better performance or 2)the ability for the engine to run submerged in water. The first I could understand on a commercial rig that may run for days, weeks, months, non stop. The second seems like overkill. If my engine is in the drink, I'm probably, or hopefully, in the life raft along with the crew and the EPIRB.



Is there any other valid reason commercial or pleasure boat wise to have an engine air intake piped above the pilothouse? I can't see a valid reason for a pleasure boat but commercial outfits are a whole different animal that I'm sure I don't completely understand.

Makes no sense to me. You want plenty of intake air, but ideally directed to the lowest point in the engine room.

While I'm sure the snorkels have water traps, still think that's begging for trouble.

Ted

In very rough weather, it is important air gets into the ER to keep the engines running.
Some rough weather boats have the ER air inlet along the protected walk around decks.

Ours is as described, cool dry air ducted in via the rooftop funnel into air filter box and straight to engine.
In reverse we have dual Davies Craig fans sucking warm air out and through the funnel.
Plus 6 x 4 inch pipes from foredeck locker to bottom of ER

O C Diver said:

Makes no sense to me. You want plenty of intake air, but ideally directed to the lowest point in the engine room.

While I'm sure the snorkels have water traps, still think that's begging for trouble.

Ted

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The snorkels I see are like a J with the opening facing down and provide the engine with fresh air directly into the air filter element. I'm sure there is a water trap somewhere. The ER is vented in other areas.

OldDan1943 said:

In very rough weather, it is important air gets into the ER to keep the engines running.
Some rough weather boats have the ER air inlet along the protected walk around decks.

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I've seen that and venting along the tops of the inside of the bullwarks.

Simi 60 said:

Ours is as described, cool dry air ducted in via the rooftop funnel into air filter box and straight to engine.
In reverse we have dual Davies Craig fans sucking warm air out and through the funnel.
Plus 6 x 4 inch pipes from foredeck locker to bottom of ER

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That's sounds like what I have probably seen.



I saw one boat that vented the ER out around the box that encases the dry stack exhaust. I can't remember the name of the vessel but was a fishing boat (shrimper) with twin 8V Detroits.

It makes the engine noise quieter. Lots of noise comes from the engine intake.

Lepke said:

It makes the engine noise quieter. Lots of noise comes from the engine intake.

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I'm sure. I've had some performance vehicles and motorcycles with hellacious intake noise.

Lepke said:

It makes the engine noise quieter. Lots of noise comes from the engine intake.

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Agreed. The majority of my engine noise is a combination of the noise radiated off the engines themselves and intake noise. Silencing the intake noise would make a huge difference, especially at higher power settings.