Identifying Green vent on bottom of hull

[theorifice]

What is this green vent? It is located on the aft of the hull and the vents are facing aft

PXL_20230415_164524549.MP.jpg

[Cooler]

That is the water pick up for your engines. The green is corrosion. Should have 1 for each engine. er

[km1125]

Like Cooler says, those are typically for the engine or generator water intake. However, you wrote that the "vents" are facing AFT. Is that accurate? They should be facing forward if they are for engines or generator.

And there should be a coat of bottom paint on those, but don't lay it on so thick as to plug up the slots.

[buster53]

Could also be air conditioning water pick up

[g36]

Or raw water head

[bud37]

Looks like there has just been some work on it by the look of the sealant and the clean gel around it.

[Viper]

Check to see if it's for the generator. It's common to see that type of intake facing aft for generator applications so you don't force water up into a generator that's not running while the boat is underway. If the generator isn't running and water is forced through the raw water pump, there's no exhaust pressure to prevent water from backing down the exhaust elbow into a cylinder.

[theorifice]

Thanks all.

The boat is a sterndrive so the water pickups are in the lower units. The boat does have AC and a generator. I saw a coolant reservoir for the generator though so it might be a closed system. I'll keep poking around and mapping out all of the fittings.

I'm not aware of any work in the last 3 years. We've owned for the last 8 months and previous owner hadn't done any work other than winterizing.

[tomschauer]

Even a closed cooling system for your generator uses raw water to cool it. It goes through a heat exchanger.

[Midnightsun]

As explained above closed cooling systems need raw water to cool the coolant since everything is enclosed in a hot bilge unlike a car which can benefit from cooler ambient air and a radiator to do the same job.