Thru-hull question

[rescuesailor]

I have a Universal 5432 diesel engine. The intake into the raw water pump is 1/2 inch. My boat currently has 13 thru-hulls. I would like to streamline and eliminate some of these. My question is this. Can I consolidate the raw water intake for the engine, salt water for the sink, and the A/C intake into one. My plan is to use an 1 - 1/4 thru-hull, same size strainer and a manifold using 1-1/4 tees with 3/4 inch take offs going to all three usage devices. I also want to incorporate a generator someday but I figured that would be too much. The problem will come when the generator is installed. It would be likely that both the A/C and the motor could run simultaneously. Any thoughts?

[Skipper599]

I have a Universal 5432 diesel engine. The intake into the raw water pump is 1/2 inch. My boat currently has 13 thru-hulls. I would like to streamline and eliminate some of these. My question is this. Can I consolidate the raw water intake for the engine, salt water for the sink, and the A/C intake into one. My plan is to use an 1 - 1/4 thru-hull, same size strainer and a manifold using 1-1/4 tees with 3/4 inch take offs going to all three usage devices. I also want to incorporate a generator someday but I figured that would be too much. The problem will come when the generator is installed. It would be likely that both the A/C and the motor could run simultaneously. Any thoughts?

Hello "rescuesailor"

Personally, I don't see a problem with what you propose as long as the 1-1/4" thru-hull will accomodate the combined water demand of all connected accessories or systems.

What I would be concerned with is, that engine cooling takes priority and there are no possibilities of coolant flow reduction caused by whatever else uses the combined intake system.

[sail_fix]

13? Wow.
My 34 footer has less below-DLW thru hulls to worry about.
Let's see... engine intake, galley sink drain, head sink drain, Head intake and discharge....

There are also some tough "thru hull" fittings for instrument transducers (2) and the solid one for the Frigoboat heat exchanger.... so that's three more holes in the hull. I would not consider those as a weakness, per se.

My other fittings were changed over to composite Forespar seacocks several years ago, epoxied to big backing plates. Very stout.

Still, I wonder how you have some many holes?

As to the engine, by the late 80's, most of those intakes were standardizing on a 3/4" size, and still are. One key thing is that, in dealing with mechanics and builders over a three decade period, I have never met even one that liked combining an engine cooling water intake with any other intake. This is because ANY loss of suction there will ruin the raw water impeller quickly, very quickly.

So, while advice from strangers on the 'net is only worth what you paid, Do Not combine the engine intake with any other intakes via a "sea chest" or "manifold."

Sincerely,
LB

(Universal M25XP)

[galleywench]

Not sure if this would be an issue or not, but if you don't have backflow preventers (1 way valves) installed on the sink and a/c intakes wouldn't you run the risk of losing suction when the engine is running (meaning the engine starts sucking air through the sink spigot)? Or maybe the manifold has those built in?
Purely speculation on my part.