Where to put raw water strainer?

Noah · Post by **Noah** » Mon Jun 25, 2007 10:32 pm

I want to install a raw water strainer between the saildrive leg (where the engine get's it's water) and the engine raw water pump. I'm doing this because I worry about crap (zebra muscles) getting sucked up into the engine.

The cockpit sole on my boat is pretty low, meaning that I have two places to install the raw water strainer, and neither is perfect:

1: Install it in the engine compartment, but between .5 and 1" below the water line. (Meaning that the screw on top of the strainer will be below the waterline)

2: Install it in the cockpit locker. I can put it just above the waterline, but it will be out in the open, and could get broken/hit by something which would be bad/sink the boat.

What say the folks here about the right place to install?

Thanks,

Noah

Figment · Post by **Figment** » Mon Jun 25, 2007 10:36 pm

I can't recall the last time I saw a strainer that was above the waterline.

Post by **dasein668** » Mon Jun 25, 2007 11:23 pm

Mine's close... But Mike's right: rarely do these things get installed above the waterline in a small boat. I wouldn't worry about it at all if you have a seacock on the intake and close it when you're not on the boat.

bcooke · Post by **bcooke** » Tue Jun 26, 2007 10:07 am

ditto

(or is it thritto?...)

Is there a common rule or something about keeping the strainer above the water line or is it a personal inclination -and I know ALL about personal inclinations :-)

My strainer is about 2 feet below the waterline. I always keep the engine raw water intake seacock closed when the engine is off so I don't worry about it. Turning on the blower, fuel and water is just a part of my startup routine.

-Britton

Post by **Tim** » Tue Jun 26, 2007 10:23 am

I think strainers end up below the waterline mostly because the engines and their related compartments are below the waterline. Therefore, the space available tends to be below the waterline, and level with or below the engine intake through hull.

Noah · Post by **Noah** » Tue Jun 26, 2007 10:40 am

The raw water seacock isn't very easy to get to, so I probably won't be closing it each time I leave the boat...It's just the way it is. Would you still put it below the waterline?

Post by **dasein668** » Tue Jun 26, 2007 10:53 am

Are you vigilant about inspecting hoses?

I occasionally forget to close my raw water intake. I try not to, but it happens. But I also keep a good eye on the condition of my hoses and clamps, so that adds a little bit of peace 'o mind.

Post by **Tim** » Tue Jun 26, 2007 11:01 am

Noah wrote:The raw water seacock isn't very easy to get to, so I probably won't be closing it each time I leave the boat...It's just the way it is. Would you still put it below the waterline?

I think what drives the decision more than anything is ease of inspection and maintenance access for cleanout. Too many raw water strainers are all but inacessible, which sort of defeats the purpose.

Let this drive your decision. Lots of hoses are below the waterline, and few are attached to seacocks that get closed all the time--we all know that most people never close these things; those who do are rare indeed. (I do.)

Good hose maintenance and regular hose replacement always comes into play, so I don't think having an open seacock necessarily dictates where your strainer will go. (Unless the strainer fails, which it shouldn't. Unless it's neglected...unless...well, you get the point.)

Quetzalsailor · Post by **Quetzalsailor** » Tue Jun 26, 2007 11:43 am

I think you'd find that the instructions for strainer call for installation above the waterline.

However, I moved my engine raw water strainer from above the waterline to well below, to get working room around the engine. An identical strainer serves the refrigerator. There are three seacocks now neatly lined up on one side of the keel; the two strainers and the refrigerator raw water pump are across from the seacocks. There's a space for another strainer and a washdown pump. I broke my own preference for being able to rod out the seacock and thoughhull by using barbed ells instead of straight barbs. We always leave the seacocks closed when we're away for the week.

Accessable seacocks are much more likely to be left closed.

Noah · Post by **Noah** » Tue Jun 26, 2007 1:16 pm

The hoses from the Intake to the engine will be brand-spanking-new, as well as the raw water strainer and all hose clamps.

I think I will put it in the engine compartment just below the water line.

I generally close most of the sea cocks on my boats. On the Swede I will probably close all but the cockpit drains and the engine intake.

Figment · Post by **Figment** » Tue Jun 26, 2007 6:30 pm

If you're in the habit of closing seacocks, why not take the opportunity (the boat's on the hard, I assume) to relocate the intake to your convenience?

[duck]

Noah · Post by **Noah** » Tue Jun 26, 2007 10:07 pm

Figment wrote:If you're in the habit of closing seacocks, why not take the opportunity (the boat's on the hard, I assume) to relocate the intake to your convenience?

[duck]

Sheesh...tough crowd. The seacock is located on the saildrive, because the saildrive acts as the raw water intake. Let's just say I'm not moving the saildrive any time soon...I think the Saildrive may even use the raw water moving through it to cool it as well.

(Well I did just replace the $380 gasket that goes between the saildrive and the boat, keeping it a-float, so I guess I did move the saildrive, but I put it right back where I got it.)