No raw water strainer = trouble?

[SV Second Wind]

Hello,

I purchased my first sailboat about two years ago and finally got around to study diesel engines. Second Wind has a Yanmar 2GM20F and I noticed there is no raw water strainer; she does have a thru hull strainer however. Is a thru hull strainer enough or am I rolling the dice by not having a raw water strainer as part of the system?

Thank you!

[Wotname]

Originally Posted by oivivio

Hello,

I purchased my first sailboat about two years ago and finally got around to study diesel engines. Second Wind has a Yanmar 2GM20F and I noticed there is no raw water strainer; she does have a thru hull strainer however. Is a thru hull strainer enough or am I rolling the dice by not having a raw water strainer as part of the system?

Thank you!

Best practice is no external thru hull strainer and a raw water strainer between the thru hull and raw water pump.

The reason for no external strainer is that these items often foul up quickly with marine growth thus restricting water flow and it is difficult to clean away the growth without either diving or slipping.

The 2GM20F is a great little workhorse and not hard to maintain. How many hours are on it?

[Stu Jackson]

Why External Strainers are a Bad Idea 101 (Maine Sail) http://forums.catalina.sailboatowner...d.php?t=124964

Get a raw water strainer.

[SV Second Wind]

Thank you @Wotname & @Stu Jackson for the prompt replies! Your feedback and link as to why external strainers are a bad idea is a sobering read. I appreciate your advice and will begin looking into raw water strainers. Any brands or models to your knowledge which stand out as reliable and durable?

@Wotname - Unfortunately, The 2GM20F does not have an hour meter. From conversation with the prior owner, the engine was installed 10 years ago and saw very little use over the years (Primarily used to get in and out of the slip, in freshwater on the Hudson River in NY. No log book to track the hours either.) My guess is she has about 150-200 hours on her. Trying to read up on as much as I can so she can see a long, healthy and trouble free life!

Thanks again!

[Sailmonkey]

I'm a fan of groco ARG strainers.

An ARG-750 would be just about right for that engine.

[sailah]

Second the Groco bronze line. I have 2 on my boat and they are exceptionally well made.

[HopCar]

A lot of sport fishing boats are doing away with internal strainers. They installed these Groco external strainers and noticed that nothing ever got to their internal strainers.
https://www.groco.net/products/raw-w...er/aphs-series

These boats tend to be well maintained and the bottom cleaned by a diver on a regular basis. If you're not going to do that, install an ARG-750 as previously suggested.

[rwidman]

Originally Posted by HopCar

A lot of sport fishing boats are doing away with internal strainers. They installed these Groco external strainers and noticed that nothing ever got to their internal strainers.
https://www.groco.net/products/raw-w...er/aphs-series
.

Those strainers came on my boat and they have been trouble free. I also have a strainer on the air conditioning line and my Volvo engine has a built in strainer.

With a strainer external to the hull, you will never ingest a plastic bag or large item.

[barnakiel]

Our boat has only the external basket.

I think it depends on how much debris in the waters you power thru.

Cheers,
b.

[Stu Jackson]

Do a search on Hobbs meters. It's an easy to install hour meter.

[HopCar]

Originally Posted by rwidman

Those strainers came on my boat and they have been trouble free. I also have a strainer on the air conditioning line and my Volvo engine has a built in strainer.

With a strainer external to the hull, you will never ingest a plastic bag or large item.

Ron, did you read that link to Maine Sail's post on why he doesn't like external strainers? He suggested that if you do use an external strainer that you put it on with sealant and not screws. That way you can knock it off from inside the boat if you have to. It occurred to me that you could hold the door on the Groco closed with sealant or a shear pin. That way you could poke it open with a stick from inside if you had to knock barnacles and oysters from inside the thru-hull.

I installed one of those strainers on Possum, but I haven't removed the internal strainer yet.

[a64pilot]

Funny, I didn't realize it, but I have both internal and external strainers.
Just had all the ones on the outside replaced with ones that have the little doors closed by a split ring, so that in case a barnacle decides to grow on the inside I can open it up and clean it out, least that was my reasoning anyway.

[01kiwijohn]

I wouldn't worry too much about the external strainer. It's not a big deal to jump over the side and clean it in the unlikely event that it does get something caught up externally.
I've had a couple of Groco jobs, where the actual strainer basket has corroded, and cracked, at the point where it is connected to the end cap.
I like the plastic, Vetus, where there's nothing to corrode and you can just look right in the top to see what's in there. That'll be my next one.