Sea Strainer Mounting
 

I am going to install GIL sea strainers in the next few weeks. I am looking for thoughts on their height. On my last boat. I mounted the strainer to a stringer below the raw water pump. A lot of the water would drain out, as it does anyways from the pump. In this boat, there is no way to get between and below the engines, so I was thinking about mounting them in a location which would put them above the pumps. This then adds to the "head" of the inlet water line. It would also prevent the pump from draining out, which could improve start-up, as it will be primed.

Does anyone have experience with this scenario?

Thanks,
Bruce...

I think it should be ok as long as the sea strainer is not above the waterline of the boat.....that woudl just add more resistance upon startup. Gravity is your frined when priming the system on startup.......if you have broken veins inthe sea water pump it may never be able to pull the water into the engine!! :eek:

Actually, if you are using a through hull pickup, the strainer must be above the water line. If it isn't the system will siphon when open.

I'm using the standard Bravo 1 outdrive pickup (through the sides).

That's interesting about mounting it with reference to the water line. I wonder if there is a rule of thumb there? Hmmm....

On inboard applications (always equipped with thru-hull pickups) the sea strainer is always located below the waterline with the boat at rest. On my Cigarette with transom-mount water pickups the sea strainers are also located below the waterline when the boat is at rest..

If below the water line just put in a valve

Yeah, I forgot to mention the seacock required for the below-waterline installation.

I just kind of assumed all systems have some sort of shut off valve.. :rolleyes: but allas you know what happens when one assumes! :)

Tell me, is the ball valve there in case a line breaks? If so, do you shut it off when you leave the boat in the water unattended/moored? I trailer mine, so is it there just in case I blow a line or something? One last question, could the water really run into the boat through the inlet on a Bravo1?

Thanks,
Bruce...

If you blow an inlet line you got big problems. I have never seen one burst but if not secured properly it may pop off. They are rated at like 400 lbs pressure. The shut off is typically right before the strainer allowing you to shut off the water while cleaning it. I usually leave mine on all the time unless cleaning.

I located the sea strainers this past weekend. They are along side each engine, on the outer most stringer - but still above the raw water pump. Any last thoughts on this elevation? It is above the water line of the boat.

Thanks,
Bruce...

I had an occasion to use those ball valves on someone else's boat. He broke an air conditioning thru-hull fitting below the waterline and was taking on water at a tremendous rate, so when he made it into the harbor and into a slip I jumped into the engine room, shut off the seacocks after he shut down the engines, and removed an engine intake hose from the sea strainer. After laying the intake hose into the bilge I had him start that engine to use it as a bilge pump. It kept the boat afloat until the Coast Guard arrived with their pumps. And by the way, I kept a guy at the engine room hatch (this was a triple-cabin Chris-Craft) just in case I needed a hand getting out of there.

Crazyhorse,
That's quite ingenious! I'm sold.
In fact, maybe I should plumb in a T with an additional line and shut-off for just such a back-up. Hmmm...

Bruce... :D

Any last thoughts on my elevation question? They will be above the inlet of the raw water pumps.

Thanks,
Bruce...

there's a valve made just for this eventuality. Check at your local boat shop for a three-way valve.

Crazyhorse,
Are you talking about an emergency suction line (or bilge pump) for the boat?

Bruce...

I started reviewing this post because I just bought a set of strainers for my Cafe.

Dumb question #1 (they were used - no instructions): Mine have two ports on the bottom, and one on the top. I'm assuming the two on the bottom are "in" and the one on the top is "out" - correct?

Dumb question #2: Do i need to add a thru-hull water pickup, or will they be ok feeding from my Bravos?

I think as long as you aren't mounting the strainer more than a few inches above the sea pump you won't have any problems... whether the strainer is above or below the water line... Rubber vane pumps are self priming and don't need water for them to begin pumping... only to lubricate them upon startup... most of the pumps hold a small amount of water within their bodies to wet the rubber when you start the engine. My boat had ball valves between the hull mounted pick ups and the strainers... just in case the strainer had to be opened. Even if the strainer is above the water line I would have a ball valve in case something in the water system broke on one engine.... you could close the valve and then motor back on the other engine without filling the boat with water. Hull mounted pick-ups sit facing the water stream and will scoop water up and generate a small amount of "head" when the boat is moving forward.

Ray - How ae the fittings in your lids holding up? That was a great idea.



The valve can also be used to shut off the hose to thru-hulls if you have a flush fitting like raypanic does or if you winterize with a fitting like this or have a tee inline.

Double clamp all the hoses like raypanic did.

O.K. I have a 24' Formula 242ls and use a Groco strainer. it is mounted to a stringer. I thru bolted it with bronze hardware and sealed bolts with 3m 5200 sealer.
Also have 1 1/4 " thru hull with a ball valve. This system is excellent and would recommend to everyone. The only thing I'd do different is put a bigger thru hull in so I can get more water when I put in a bigger motor. It's not cheap at all to buy a bronze seawater pump and groco strainer and a strainer on the bottom of the boat, a flush kit and hardware and the pump brackets and the pulley, but that's the reason why they don't come on boats from the factory. It's good insurance against frying a motor. Also a temp alarm for $30 is a great deal. I run a slightly modified 365 mag motor with a 140deg t-stat and it never goes over 140deg. I have to contend with seaweed and salt water. Maybe elsewhere you can do without all this hassle. I would do this to a smalblock cabin cruiser too. Both my boats are setup like this, My smaller boat does not have the inside strainer and has not had a problem since setting it up my way ! :) I leave the ball valve open when unattended. It's a very solid system. I'd never trust a pvc thru hull fitting either but thats just me. Inadequate cooling is probably the most overlooked area that cause premature engine failure. (people feel hey! it's a boat, it's surrounded by water of course it's getting plenty of water) :rolleyes: BBB

Cignificant, I'm certainly thinking that the top ports are the "in" (from pickup) and the bottom(s) go to the pump.
The sea strainer collects debris on top of the screen.

Thx, I'll peak at some in Miami next week to make sure.

Yes that's correct ;)

After in stalling the strainers and take your first ride, monitor the water pressure guage. You sould have 20 to 25 psi when cruising. Any thing over 30 psi. will make head gaskets leak to the outside and may blow off a circulator hose. Then you need merc's water bypass kit.Anything under 15 psi. and you could start making steam pockets in the heads or block. Thats BAD. It can hang up an exhaust valve as it heats up at high speed. Then BOOM!! That means you may need a little longer pickup or if a bravo has side pickups you need to plug the 3 upper holes on each side.