GoFastSonic

I am installing a 5000 btu AC unit im my 2001 sonic 31 SS. My question is has anyone ever used the hose from the outdrive that sends water to the raw water pump? Does that hose have water in it at all times or does the raw water pump pull it up to the motor? The reason being is that I do NOT want to put a hole in the bottom of the boat if I can help it? Any thought on the matter would be apreciated.

Michael

JohnnyG

I'm no expert, but it seems to me that the suction created by the raw water pump on the engine wouldn't allow much or any water into the AC system. This means it probably wouldn't ever work while the engine was running.

I know that the water pumps on the AC units are typically not very big and usually not self priming also. They rely on being below the water line in order to function. This may also present a problem if you're trying to use the outdrives water supply. Even though it is below the waterline on the outside of the boat, it can't possibly remain so all the way into the engine room.

We have a Mermaid system on our 32SS with a brass thru-hull and a ball valve. Seems to work fine. I hate extra holes in the boat too, but that's the price you pay for more gadgets and amenities.

Wally

Do you have a sea strainer? many boaters use that as the water source for the pumps ont he A/C systems.
JohnnyG is right that the pumps do need to be below the water line as they are not self priming.
The boats that have systems that work when on plane have their own sepperate thru-hull pickup for the a/c system.
As long as your not planning to try and use the A/C when running i think you would be able to use the main water line from the drive.....just make sure theres no sea-weed blocking the intakes of the drive

GoFastSonic

I do not have a generator so no problem not using the air underway. But when I look at the hose from the drive to the pump it looks like it comes out of the top of the bell housing which I do not think is below the water line. Guess it is off the lift on tuesday on the trailer and chop chop with the hole saw. Thanks for the advice and let me know if you have any other ideas please.

Michael

US1 Fountain

True, but not neccessarily. I run my AC with the boat on the lift. Just gotta be creative.

Turbojack

i would be concerned that using the engine water you might cause the engine to not get enough water or cause the engine water pump to suck air by backfeeding thru the AC cooling system.

GoFastSonic

I thought about it sucking air from the ac unit while runing but figured a ball valve on the ac hose would solve that.

t500hps

Install in a buddies Nordic they put the intake hole for the A/C on the transom down near the drain plugs. These are nice and deep in the water when at the dock, but out of the way and create no extra drag when underway.

Wally

Oh i think ive head them all by now seeing as i get about 5 calls a week from boaters asking questions about their pumps!

Yes there are ways of getting creative and getting them to work......theres more then a few guys ive spoken to that have cruisers that have put a "T" on the out put line to use as a fill line to prime the pump up.....theres even a few that have installed one way valves to keep from loosing the prime of the pumps....
One thing you have to remember and take into consideration on your setup when running on the lift US1.....when the pump is working and is above the water source you loose output capacity due to the fact its lifting the water...so its working first to lift, and then to try and pump....we have formulas to figure out what kind of output you would get but it drops off quite a bit the higher you get.
Now if you have agrden hose connection in the system for running on the lift.....then only thing you have to worry about is city water pressure.....The March pumps are only good to about 50psi on internal pressure.....city water pressure can be anywhere from 30psi as high as 65psi....hopefulyl you have a psi regulater on the inlet line to limit it..if not youll probably get leakage around the O-ring seal sooner or later....besides that, our little pumps "just about" never go bad. Ive got more then a few calls from boaters that have pumps go out on them after 15+ years and are looking for replacement parts!!! About the only thing you cant replace on our pumps is the motor as they are sealed in epoxy.

rdoactive

The AC water pumps have a hard plastic impeller and are magnetically coupled. If you T before the water pump, I would think the engines water pump would easily suck air backwards through the AC line. A one way or shutoff valve might work, but I expect the engine water pump would collapse the small hose to the AC pump. The hose probably wouldn't last long then.
Why not do it right? Go ahead a drill a hole in the bottom of your boat. I would prefer to drill through a non-cored hull than a wood cored transom for obvious reasons.
BTW, if you're only going to use it resting at the dock, a round "hole" thru hull at the bow will work as long as he pump is below the water line.
You'll need a scoop type pickup near the transom if you're going to get a gen and use while running.
Gary