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Leaking sea strainer

Epenn

1985 E30+, San Francisco, CA
Hey all,

I just replaced my sea strainer with a plastic half inch Groco. It leaks out of both the fitting and the basket. I tried adding Teflon tape (maybe too much) and it still leaks, though much less. Is it likely defective? Is this a common issue? Is there a better quality part I can find?

Thanks,
Evan
 

gabriel

Live free or die hard
Evan,

when I replaced a seacock a few months back I put standard Teflon tape on the thruhull threads but it leaked slightly, so I disassembled and put extra thick and it solved the leak.
 
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Loren Beach

O34 - Portland, OR
Senior Moderator
Blogs Author
Our boat was built w/o a sea strainer, so I installed a cast plastic (Wilcox Critenden) one right after we bought it. Within about 5 years it developed cracks - probably from flaws in the casting process. Luckily I had bought it from WM, and they, after some convincing, took it back for a full refund.
I installed a Groco bronze one and it still looks almost like new. Good product. Perhaps normal engine vibrations are just bad for the "plastic" ones?
You may have to adapt the fittings, but if your boat has an OEM half inch thru hull, that would be best replaced with a 3/4" version at next haul out.
Another mod we did at the same time was installing the Forespar 3-way thru-hull for easy flushing. It's a great upgrade for any boat.
Link with picture -
 

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  • Groco bronze.jpg
    Groco bronze.jpg
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Kenneth K

1985 32-3, Puget Sound
Blogs Author
Against better advice, I installed a plastic engine strainer too, a few years ago. A bronze strainer is usually recommended in the engine compartment for this vital application. However, sizing and location is a factor with these engine compartments and I really liked the smaller plastic strainer.

In the contest of bronze fittings screwed into a plastic housing, the bronze is always gonna win--the plastic will break first and somewhat easily. However, mine has been fine for over 3 years. Knowing the plastic fittings are the weak point, I first wrapped the outside of the fitting several times with tightly wrapped electrical tape. Then I put hose clamps around the tape. This combination is meant to keep the plastic fitting in compression and help prevent cracking when bronze fittings are tightened in place. Then I put a liberal amount of PTFE pipe sealant on the bronze threads before assembling. The PTFE paste sealant provides the same benefits as teflon tape. but it flows and fills in the voids better. You still need to be careful about not over-tightening. Mine has been leak and crack free for years.

Many will still simply recommend a bronze-bodied strainer, for good reason. Note also that if your strainer leak is below the waterline, and you leave the raw water thru-hull open, you have an open, below-waterline leak that can sink your boat.

20170920_110218.jpg 20170920_110030.jpg
 
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Kenneth K

1985 32-3, Puget Sound
Blogs Author
Another mod we did at the same time was installing the Forespar 3-way thru-hull for easy flushing. It's a great upgrade for any boat.
Loren, is that a 3-way thru-hull fitting, or a 3-way valve installed downline from the thru-hull? Can you post a picture?

I put in a Groco SSC valve 20170920_110030.jpg which does allow engine flushing, but not "on the fly." The engine has to be stopped first, then the SSC opened and connected to its own hose, then the engine restarted for flushing. It works, but not as conveniently as a 3-way valve might.
 

nquigley

Sustaining Member
Here's the plumbing for my raw water antifreeze flush option.
This pic has the plumbing set for raw water cooling.
For antifreeze flushing, I put the bitter end of a ~4' hose (seen leaving the frame at about 2 o'clock in this pic) in a bucket of antifreeze, open the yellow-handled valve, and then close the the raw water seacock - its yellow spray painted black handle is just visible. I shut the engine down when the pink antifreeze comes out with the exhaust. One can do this switch-over with the engine running with raw water, or start the engine with the valves already set to flush with antifreeze.
Raw water flush plumbing.JPG
 

Loren Beach

O34 - Portland, OR
Senior Moderator
Blogs Author
Loren, is that a 3-way thru-hull fitting, or a 3-way valve installed downline from the thru-hull? Can you post a picture?

I put in a Groco SSC valve View attachment 38794 which does allow engine flushing, but not "on the fly." The engine has to be stopped first, then the SSC opened and connected to its own hose, then the engine restarted for flushing. It works, but not as conveniently as a 3-way valve might.
The link to our picture is in reply 3. That Forespar 3-way thru hull seacock fitting is a great design. It can replace your old skin fitting for the engine water intake.

And here is another link with more pix:
 
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Rocinante33

Contributing Partner
I installed a Marelon raw water strainer a few years back. It was one of these. No service issues nor problems, happy to say.

I thought at the time that the Marelon is good and strong, same type material as the entire hull is made from. I think it may have been a more compact (shorter) model.

 

Epenn

1985 E30+, San Francisco, CA
Thanks for the replies everyone. A couple weeks later the leak seems to have lessened, but my plan is still to go to WM and try a different specimen. I'll let you know how it goes.
 

ddoles

Member III
I installed the Forespar Marelon strainer mentioned above maybe 7 years ago when I bought the boat as it did not have a strainer. It has performed flawlessly. I'm very happy with it. I will also note that all the fittings are also Marelon, so no plastic vs metal issues.
 

vanilladuck

E32-3 / San Francisco
Blogs Author
Appreciate the thoughts and photos in this thread! I just installed a sea strainer on my E32-3. As far as I know it never had one before. I bought a Groco ARG-755-SBC, which has a stainless steel basket and all bronze construction. Thinking about it now, I probably could have gone with an ARG-500.

The in/out ports on the ARG-755 are 3/4" NPT. I had a bit of a mismatch in hoses for my raw water pickup on the M-25. The seacock was a 3/4" barb, but the Oberdorfer raw water pump has 5/8" pipe connections. I had to construct an adapter for the outlet side of the Groco with a 3/4" NPT to 5/8" barb. Don't worry, that's not a brass fitting. It's "polished bronze"

PXL_20230514_004138828.jpg PXL_20230514_004145984.jpg

The idea for the backboard is great. Holds the strainer at just the right position and allows for routing of hoses under and behind while also keeping the starboard side of the engine relatively accessible.

PXL_20230514_021747670.jpg
 

Pete the Cat

Member III
I have used a plastic Vetus sea strainer on my Tartan 37 for about 25 years with no problem. I think most of the plastic sea strainers suggest that they should be placed above the waterline relative to the engine. The bronze ones can be put lower if that is not an option. I actually have been surprised that in several thousands of hours of running in many conditions at how little grass and junk it has trapped. I noted that my Ericson came without a strainer. I have one to add when I next replace the engine feed hose, but I have not been in a hurry. I am questioning how necessary a sea strainer is if you have an exterior screen on the intake and your engine intake is an inch or less. The pump will macerate any organic stuff that might come in. I regularly service my heat exchangers and they are generally clean except for salt buildup. One problem I have seen is that some boatyards do not remove, clean and paint the inside of the exterior screen when doing a bottom job. I suggest you insist. FWIW. This is my thinking after many years. Others will have other opinions.
 

Christian Williams

E381 - Los Angeles
Senior Moderator
Blogs Author
I actually have been surprised that in several thousands of hours of running in many conditions at how little grass and junk it has trapped

Me too. I did find some minor salts buildup, but not as much as on the outflow of the Oberdorfer salt water pump, which is next in line.

I think the bronze Groco was standard on the 381.

IMG_5400.JPG...IMG_5391.JPG
 

Nick J

Sustaining Member
Moderator
Blogs Author
Appreciate the thoughts and photos in this thread! I just installed a sea strainer on my E32-3. As far as I know it never had one before. I bought a Groco ARG-755-SBC, which has a stainless steel basket and all bronze construction. Thinking about it now, I probably could have gone with an ARG-500.

The in/out ports on the ARG-755 are 3/4" NPT. I had a bit of a mismatch in hoses for my raw water pickup on the M-25. The seacock was a 3/4" barb, but the Oberdorfer raw water pump has 5/8" pipe connections. I had to construct an adapter for the outlet side of the Groco with a 3/4" NPT to 5/8" barb. Don't worry, that's not a brass fitting. It's "polished bronze"

View attachment 47038 View attachment 47039

The idea for the backboard is great. Holds the strainer at just the right position and allows for routing of hoses under and behind while also keeping the starboard side of the engine relatively accessible.

View attachment 47040
Bryon,

Your sea strainer install looks great and should be really easy to access for maintenance. On a different note, The sink drain hose has been mentioned on the forum a few times (https://ericsonyachts.org/ie/threads/terra-nova-flooding.14156/), but can not be overstated. All the original hoses in my boat that looked like that either had cracks or cracked as soon as I touched them.
 

nquigley

Sustaining Member
Appreciate the thoughts and photos in this thread! I just installed a sea strainer on my E32-3. As far as I know it never had one before. I bought a Groco ARG-755-SBC, which has a stainless steel basket and all bronze construction. Thinking about it now, I probably could have gone with an ARG-500.

The in/out ports on the ARG-755 are 3/4" NPT. I had a bit of a mismatch in hoses for my raw water pickup on the M-25. The seacock was a 3/4" barb, but the Oberdorfer raw water pump has 5/8" pipe connections. I had to construct an adapter for the outlet side of the Groco with a 3/4" NPT to 5/8" barb. Don't worry, that's not a brass fitting. It's "polished bronze"

View attachment 47038 View attachment 47039

The idea for the backboard is great. Holds the strainer at just the right position and allows for routing of hoses under and behind while also keeping the starboard side of the engine relatively accessible.

View attachment 47040
Just sharing another view of the same space in another 32-3. The 2 small seacocks are OEM. I replaced my sink and cockpit drain seacocks with TrueDesign units a couple years ago - I'll replace the other two (and probably those in the head cabinet) at my next haul-out.32-3 655 under sink.jpg
 
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