Through hull strainer

Ted

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Jan 26, 2005
1,254
C&C 110 Bay Shore, Long Island, NY
We had different opinions at the boatyard today regarding the correct way to install a through hull strainer like the one in this photo. Should the closed (solid) portion face forward or should the openings face forward. Extra credit if you can document your answer.
Screen Shot 2018-05-20 at 7.22.33 PM.png
 
Oct 24, 2010
2,405
Hunter 30 Everett, WA
No documents but i think facing forward would use hydraulics to force debris into it. Facing aft it would tend to clean it.

Ken
 
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Jan 11, 2014
11,321
Sabre 362 113 Fair Haven, NY
There was a discussion of this in some sailing/boating publication (Professional Boat Builder?), just can't remember the source. The issue was the water pressure with the scoop facing forward. The hydraulic pressure had the potential to force water up through the system. If I recall correctly, it was recommended to place the opening facing aft.
 
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May 17, 2004
5,028
Beneteau Oceanis 37 Havre de Grace
May 20, 2016
3,014
Catalina 36 MK1 94 Everett, WA
facing aft is correct - but that is a power boat strainer -- sail boats should have the round one full of holes, or even better no external strainer. Just like Davidasailor26 said
 
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Jun 21, 2004
2,532
Beneteau 343 Slidell, LA
Interesting, on my Beneteau there was one for the engine raw water intake and one for the shaft seal cooling water. One strainer faced forward and the other aft. I removed both of them and installed conventional thru hulls with no strainers. When I first got the boat & had it hauled, the strainers were significantly clogged and I could not clean them to my satisfaction. I removed the external screws; however, I couldn’t remove the strainer covers. After beating the strainers with a hammer, I realized that the strainer was actually a one piece casting with the thru hull as pictured in the previous post. No way to clean it, so I replaced them with open flanged thu hull fittings.
 
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Gunni

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Mar 16, 2010
5,937
Beneteau 411 Oceanis Annapolis
For engine raw water use the the slots are oriented to the aft of the boat. For the shaft seal the slots are oriented to the bow of the boat. For random drains I would orient them with the slots aft to facilitate suction out of the boat. We have a problem around the Bay with young herring fry hiding in open thru-hull ports and getting sucked up into the hose so we keep ours in place.
 
Dec 19, 2006
5,809
Hunter 36 Punta Gorda
I don’t like that type of strainer because they are very hard to clean out and easy to collect barnicales inside it and hard to clean
Nick
 

Ted

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Jan 26, 2005
1,254
C&C 110 Bay Shore, Long Island, NY
So.........to further muck things up, I contacted Buck Algonguin (the manufacturer of the strainer in question) and here is their response.

"We appreciate your interest in our products and we would be glad to help out. For this item you should have the the openings or slots facing forward toward the bow of the boat."

Stumped!
 
Apr 8, 2010
1,942
Ericson Yachts Olson 34 28400 Portland OR
Just because the responder works there does not guarantee that they always know what they are talking about.
Rather than info from a vendor, I would listen to a repair professional like Maine Sail.
 
Jan 10, 2018
260
Beneteau 331 Halifax
Hi, I have a new to me Beneteau 331, and I just checked these out this past weekend. The round part without the slots is underneath the hole on the hull, so the slots face forward.

I never liked these and never used them. Mine has one screw on the thing which I undid but I could not get the strainer off. I think it is all one piece. I cleaned it, vacuumed with a shopvac, and painted it well.

Can you remove the strainer?
 

Gunni

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Mar 16, 2010
5,937
Beneteau 411 Oceanis Annapolis
If you want anti fouling paint to stay on a bronze fitting you first need to paint the fitting with epoxy barrier paint.
 
Dec 25, 2000
5,702
Hunter Passage 42 Shelter Bay, WA
Facing aft it would tend to clean it.
Hi Ted, the original one on our boat installed by Hunter, like the one in your photo, faces aft to help prevent debris from being sucked into the sea water strainer.
 
Jun 21, 2004
2,532
Beneteau 343 Slidell, LA
Bluenose,
No you can not remove the strainer. The strainer is a continuous part of the thru hull casting. If you want to get rid of the strainer you have to replace the entire thru hull fitting. I had two of them on my boat, one for the raw water intake for the motor and one for the stern tube / shaft seal cooling water supply. Changed both of them because they were blocked with barnacles.
If you decide to replace, check out Groco,s bronze fittings with BSPP threads. The threads for the thru hull fitting, ball valve ,& tailpiece all have matching threads.