Bertram31.com General Bulletin Board

Re: RAW WATER INTAKE

Posted By: Capt Patrick McCrary
Date: Thursday, 17 February 2005, at 9:00 p.m.

In Response To: RAW WATER INTAKE (phil)

Phil,

First, thank you for not using all upper case letters in your post!

I find that the most convenient location for the main raw water intakes is in the center bilge just forward of the fuel tank. We also only use Full Flow valves & external strainers for the engine water.

Your future Cummins diesel will need a genuine 2" of water flow. You can achieve that mark by going with either full flow ball valves or 2 1/2" standard ball valves, but the 2 1/2" standard will be much more bulky, you have a larger reduction to be made at the engine, and the cost will be nearly the same as the full flow by the time the job is complete.

I also like to up size my strainers and install the next size larger strainer than the valve has to have.

Internal or external strainers have frequently been a topic of debate here. I've been using, and running boats with, external strainers for the past fifteen years and have never a problem with them. On the other hand, I've run plenty of boats with internal strainers and constantly have a head ache from them.

The clam shell external strainer used in association with the internal strainers block only large debris, allowing grass and weed to pass freely into the strainer basket. The basket gets clogged and has to be checked and cleaned frequently. Barnicales & even oysters lock onto the plastic chamber walls. At least one a year, sometimes more often, the internal strainer has to be dismantled & boiled out with acid. A real pain in the ass...

Then the strainer baskets usually fail and have to be replaced at least every two years or so.

The shear space consumption of a pair of 2" internal strainers is ludicrous.

The external strainers do exactly the same job, in the same way, but are essentially self cleaning in regards to debris. Yes, barnacles can attach to the screen, but almost all of us have a dive service that maintains the bottom on at least a monthly basis. (That is, however, the reasoning behind using the next size larger strainer.)

Best regards,

Patrick

Messages In This Thread

RAW WATER INTAKE
phil -- Thursday, 17 February 2005, at 10:39 a.m.

Re: RAW WATER INTAKE
Randy Cootes -- Thursday, 17 February 2005, at 10:57 a.m.

Re: RAW WATER INTAKE
Capt Patrick McCrary -- Thursday, 17 February 2005, at 9:00 p.m.

Re: full flow vs. regular
Joef -- Friday, 18 February 2005, at 1:24 p.m.

Re: full flow vs. regular
Capt Patrick McCrary -- Friday, 18 February 2005, at 7:22 p.m.