Raw water intake strainer

Jan 27, 2022
9
Hunter 30C 5 Barnegat, NJ
The raw water intake for the 2GM20F on my H30 does not have a strainer. The PO told me that he has had sea grass sucked up into the intake and had to disassemble parts of the heat exchanger to clean it out. Since I'll be spending time in the shallows of Barnegat Bay, I expect this may be an issue for me. Does anyone have a strainer on the raw water intake for their Yanmar? If yes, what model and how/where is the best place to mount it?
 
Sep 25, 2008
7,111
Alden 50 Sarasota, Florida
Would you want stuff clogging up a strainer which is easily cleaned or a heat exchanger which isn’t…?
Once you figure out that answer, select between a number of good brass strainers - the cheap(er) plastic ones can break more easily and size it based on the GPH rating of the water pump. Bigger is better.
 
Oct 6, 2007
1,035
Hunter H30 1982 Chicago IL
I installed one in my engine compartment a few years ago. Before that I only had the original slotted scoop type through-hull but those are a problem in some waters. I put the strainer above my primary fuel filter, about at waterline level, maybe slightly above. Could have put the fuel filter above the strainer, but thought it would complicate filter change cleanup. Also need clearance above to remove the strainer basket. I have to lift the strainer off it’s bracket for wrench access when I change the secondary fuel filter, but that takes seconds. The bracket is designed for exactly that situation. It’s Groco brand. Don’t know the model number, but it was likely the smallest available. Don’t use the plastic ones in the engine compartment. They’re smaller and less intrusive, but they get brittle with age and the heat from the engine may accelerate that.
Edit: One more thing. For solid mounting of the brackets, I cut out sections of the insulation, inserted wood blocks and covered them with mylar insulation seam tape. Everything is through-bolted in the locker below the galley sink.
E96AD3C2-D16D-474E-B20B-451AADB791A9.jpeg
 
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Mar 6, 2008
1,109
Catalina 1999 C36 MKII #1787 Coyote Point Marina, CA.
There are strainers that are connected inside after the throughull resembles a colander . Do you have one of those? Or are you refering to the grill that is outside the hull?
.
 
Mar 6, 2008
1,109
Catalina 1999 C36 MKII #1787 Coyote Point Marina, CA.
Dalliance, I love your clean engine and ample space. Would it make it easier if you exchanged the oil and water filer locations?
 
Oct 6, 2007
1,035
Hunter H30 1982 Chicago IL
Dalliance, I love your clean engine and ample space. Would it make it easier if you exchanged the oil and water filer locations?
Yes and no. Wouldn’t have to take off the strainer for secondary fuel filter access, but need clearance above the strainer to pull the basket out anyway and didn’t want diesel dripping over the strainer when I change the primary fuel filter. The bracket is designed to easily lift off the strainer. Just release the bottom strap and the upper bracket is in two parts; one bolted in place and one integral to the top of the strainer. Just need to allow a little slack in the hose length so there is no need to deal with the hose clamps.
BTW, I mistakenly called my fuel filters oil filters, which I just corrected.
 
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May 17, 2004
5,103
Beneteau Oceanis 37 Havre de Grace
For what it’s worth we had a boat in Barnegat Bay for many years without a strainer. We did have to clean the heat exchanger periodically, but it was an M-12 on an O’Day 28 where the exchanger was pretty accessible.

Im not saying I’d recommend that approach - certainly a strainer would have more filtering capacity and be easier to clear - but it is not unprecedented.
 
Jan 24, 2017
666
Hunter 34 Toms River Nj
Jrzsalor,
You definitely what to have a good accessible strainer in Barnegat bay, especially in August when the sea grass is the worst. Just a suggestion when installing the strainer be sure to make sure that it is just below the water line. If you install it above the water line you may experience problems with air lock and priming.
unfortunately I installed a strainer for an air conditioning unit just at the water line due to space limitations and it’s been a pain in the a** every season.
 
Oct 6, 2007
1,035
Hunter H30 1982 Chicago IL
Jrzsalor,
You definitely what to have a good accessible strainer in Barnegat bay, especially in August when the sea grass is the worst. Just a suggestion when installing the strainer be sure to make sure that it is just below the water line. If you install it above the water line you may experience problems with air lock and priming.
unfortunately I installed a strainer for an air conditioning unit just at the water line due to space limitations and it’s been a pain in the a** every season.
Good point. When I installed my strainer at or just slightly above the waterline, I did have some concern about priming and the lift power of the pump, but it’s been six or seven years now and I’ve had no issues at all with the 2GM pump. I would not go any higher though.
 
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RoyS

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Jun 3, 2012
1,742
Hunter 33 Steamboat Wharf, Hull, MA
You should have both; an exterior thruhull strainer and a Groco interior type like the one on Dalliance above. I had both for years without issue. Then I removed the exterior thruhull one and soon ingested a jellyfish which completely blocked the raw water hose. The following haul out I reinstalled the thruhull strainer and have sailed without incident ever since. Suggest you have both.
 

jviss

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Feb 5, 2004
6,748
Tartan 3800 20 Westport, MA
You should have both; an exterior thruhull strainer and a Groco interior type like the one on Dalliance above. I had both for years without issue. Then I removed the exterior thruhull one and soon ingested a jellyfish which completely blocked the raw water hose. The following haul out I reinstalled the thruhull strainer and have sailed without incident ever since. Suggest you have both.
I agree with Roy. I'm moored in a river, and when it ebbs a lot of grass from upstream farms comes down. On my previous boat I had an external screen, as well as an inboard strainer. I almost never had to empty the strainer, and I ran the engine a lot, charging batteries. On my new boat there's no exterior strainer, and I am ALWAYS emptying the internal one: grass, minnows, jellyfish, you name it. It's a pain. I'd like to put on an external one.

Note Mainesail is wholly opposed to those external screens, so YMMV. :)
 
Aug 10, 2010
106
Hunter 36, Quarter Berth Model Placid Harbor, Cuckold Crk, Patuxent River
We have a "plastic" strainer on our H36 - re-powered with a Kubota 4-cylinder. It is mounted a few inches above the water line. We keep her on the mid-southern Chesapeake Bay - it doesn't catch too much "junk" - but it does it's job I guess. BTW - that's got to be the cleanest engine compartment I've ever seen on a 80's Hunter! Kudos Dalliance.
 

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Oct 6, 2007
1,035
Hunter H30 1982 Chicago IL
You should have both; an exterior thruhull strainer and a Groco interior type like the one on Dalliance above. I had both for years without issue. Then I removed the exterior thruhull one and soon ingested a jellyfish which completely blocked the raw water hose. The following haul out I reinstalled the thruhull strainer and have sailed without incident ever since. Suggest you have both.
I still have the exterior through hull strainer and would never give it up. The potential issue in my Lake Michigan waters is getting Zebra Mussels inside the slotted screen, but I haven’t seen any of them in years. Nothing that an occasional knife blade between the slots won’t take care of if we have another flare up.
When the slotted screen is worth it’s weight in gold is the trip to and from winter storage on the Chicago River; five hours minimum for our scheduled flotillas through the lock and 24 draw bridges. The river is cleaner than used to be, but there is still debris and it’s exponentially worse if there has been a recent heavy rain. I’ve towed other boats on portions of that trip when they over heated after sucking debris into unprotected through hulls.
Now the icky part. You might think Jellyfish aren’t an issue here, but Chicago storm and sanitary sewers are a combined system. If there has been a rainstorm heavy enough to overwhelm the sewage treatment system, the overflow gets released into the river. Floating used condoms that were flushed are called Chicago River Jellyfish.
 
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Jan 27, 2022
9
Hunter 30C 5 Barnegat, NJ
Interesting. I don't think I have a slotted intake strainer on mine. I'll check next time I'm at the yard.
 
Apr 22, 2011
870
Hunter 27 Pecan Grove, Oriental, NC
I'm happy with this Vetus strainer on my 2gm20f. Well built and easy to remove and clean the strainer.

 

RoyS

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Jun 3, 2012
1,742
Hunter 33 Steamboat Wharf, Hull, MA
The raw water pickup for the head on Katie Rose had a thru-hull strainer only. This worked until it didn't. One night at anchor the head pump stopped working. A single strand of eel grass had slipped in and fouled the pump valves. After that I added a Groco internal strainer for that line and no problems since.
 

Ward H

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Nov 7, 2011
3,655
Catalina 30 Mk II Barnegat, NJ
My Catalina came to me with a very small cheap plastic Shut Flo strainer. I replaced it with a bronze Groco ARG series strainer. Same type Dalliance shows in his pic. Works very well catching the sea grass. Quick and easy to open, clean the basket and close.
I don't have an external slotted strainer, few boats in my marina do.
The bay is pretty clean so maybe that makes a difference.
 
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Jun 4, 2004
834
Hunter 340 Forked River, NJ
I sailed on Barnegat Bay for many years on my 1980 H30. The original factory raw water intake was just a round 1/2" fitting that easily clogged with sea grass. I replaced it with a 3/4" slotted thru hull strainer with the slots facing aft. I also added a sea water strainer inside the boat but with the aft facing slotted strainer I hardly ever got sea grass in the bowl. There can be large mats of floating sea grass in the Bay and if I could not avoid them I would just throttle back and let the boat glide through them, reducing the suction from the raw water intake - saved a lot of problems for me.
I also installed an aft facing raw water slotted strainer on my later 2000 H340 and had the same eel grass free motoring on Barnegat Bay.
 
Jan 27, 2022
9
Hunter 30C 5 Barnegat, NJ
I'm happy with this Vetus strainer on my 2gm20f. Well built and easy to remove and clean the strainer.

I'm concerned about installing a plastic strainer at or below the waterline. I'm afraid the heat of the engine compartment would make the plastic brittle, over time.
 
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