Strainers for air-conditioning raw water intake

P-Dogg · Post by **P-Dogg** » Wed Sep 12, 2012 6:47 pm

I have the option to upgrade the strainers on my A/C raw water intakes (That's code for the fact that my boat is now a tree fort). I originally had this kind, which is a PITA to clean:

So now I am considering this one, which is easier to clean:
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or this one, which is not a scoop (it is what I plan to install for the generator raw water) but is low cost, and the easiest to clean:

or this one, which is a tad on the large side. That means more money, and more drag. It is, however, my current favorite to put on my engine raw water intakes:

Soooooo, do I really need a scoop strainer on my A/C raw water? Is the round hinged one satisfactory? Is the two-piece oval scoop better for some reason? Do I even need an outside strainer if I have inside strainers? Thanks in advance. Perry

PS -- Aaron you had better not post the yard pictures before I can! My camera battery died and I can't download them.

prowlersfish · Post by **prowlersfish** » Wed Sep 12, 2012 9:07 pm

forget the top 2 , you'll suck up sea grass and sea weed etc right in to the engine the last one will do a good job , the holes are too small to let much pass thru .

I am running something like this ( mine don't have the removable plate)

Perforated type not slotted http://www.deepblueyachtsupply.com/mari ... -strainers

really more like this but larger ( I have 2" intakes for the diesels )

Used them on several boats even one with inside strainers and never had to clean the inside strainers be cuse nothing got thru the them .

I have thousands of hours on these types no issues

Almost forgot , drag will not be a issue

aaronbocknek · Post by **aaronbocknek** » Thu Sep 13, 2012 3:39 am

QUOTE.....
PS -- Aaron you had better not post the yard pictures before I can! My camera battery died and I can't download them.

perry, you have no IDEA how i'm plutzing to post yard pics. but, i'll yield to you my friend, especially after the 'bet'. remember what phil said that day..... lol i did send them to dad though, and he's absolutely FASCINATED with the underwater exhaust system, especially once it's broken down into parts. he loves the amount of bronze used and the clean welds between 'down draft' pipe and hull plate.

aaron

vabeach1234 · Post by **vabeach1234** » Fri Sep 14, 2012 9:16 am

Paul,
He is asking about the strainer for A/C not the engine raw water.

I currently do not have a exterior strainer on my A/C raw water thru, just an interior strainer. If I leave the sea cock open when I get on plane, air gets in the line and I have to prime the system before I can run the a/c unit. I guess my F26 doesn' have enough draft for me to mount my A/C pump under water so that the pump can reprime it's self. When I haul out next, I plan on mounting a exterior strainer. My first preference would be a scoop type so I don't have to close the sea cock all the time but the A/C thru hull is ahead of my transducer so I'm concerned that they may cause too may bubbles in front of it giving me false readings on my fishfinder. I may just mount a round one and just keep closing the sea cock when I leave the dock. Also, if I have a scoop type scrainer, I guess that would push water through the system while on plane. I don't know if that would be an issue.

If your's doesn't lose it's prime when on plane, you may want to use the lower profile one.

aaronbocknek · Post by **aaronbocknek** » Fri Sep 14, 2012 9:20 am

vabeach1234 wrote:Paul,
He is asking about the strainer for A/C not the engine raw water.

I currently do not have a exterior strainer on my A/C raw water thru, just an interior strainer. If I leave the sea cock open when I get on plane, air gets in the line and I have to prime the system before I can run the a/c unit. I guess my F26 doesn' have enough draft for me to mount my A/C pump under water so that the pump can reprime it's self. When I haul out next, I plan on mounting a exterior strainer. My first preference would be a scoop type so I don't have to close the sea cock all the time but the A/C thru hull is ahead of my transducer so I'm concerned that they may cause too may bubbles in front of it giving me false readings on my fishfinder. I may just mount a round one and just keep closing the sea cock when I leave the dock. Also, if I have a scoop type scrainer, I guess that would push water through the system while on plane. I don't know if that would be an issue.

If your's doesn't lose it's prime when on plane, you may want to use the lower profile one.

scoop strainers work best as they tend to force water through your system thus negating the need for you to reprime.
aaron

prowlersfish · Post by **prowlersfish** » Sat Sep 15, 2012 10:45 am

vabeach1234 wrote:Paul,
He is asking about the strainer for A/C not the engine raw water

Yes I missed that the top of the post , However if you look at the midde and bottom parts P-dogg is talking about the genset and the engines ( I missed it my self ) I was only refering to the engines on my post .

One important note NEVER EVER put a scoop intake on a genset . you can flood the engine with water .

prowlersfish · Post by **prowlersfish** » Sat Sep 15, 2012 11:00 am

Ken , can you mount the thru hull and pump farther aft ? rember the close to the thru hul the pump is the better , pumps push much better then they pull .

prowlersfish · Post by **prowlersfish** » Sat Sep 15, 2012 11:40 am

I don't thing a scoop is need on the AC , I have never had a issue my self .

vabeach1234 · Post by **vabeach1234** » Sun Sep 16, 2012 8:08 am

prowlersfish wrote:Ken , can you mount the thru hull and pump farther aft ? rember the close to the thru hul the pump is the better , pumps push much better then they pull .

Yeah I know, but I hate adding new holes to the boat. I reused the thru hull for the head raw water pick up for my a/c. Then plumbed down the waste pump out thru hull and use that as the new head pick up. The head now only goes to the tank and I have no way to discharge overboard. I'm never in waters were I can legally pump overboard anyways.

AndyF32 · Post by **AndyF32** » Sat Sep 29, 2012 2:22 am

On my F32 I had installed the water intake all the way aft on center line and had the round non-scoop style intake. The issue I found was that when I went out and got up on plane it would create a vacuum and drain the intake line causing the pump to loose prime. Remembering to close the hull valve when going out solved the problem. The scoop style would have forced water back thru the system.