Which Type of Intake Strainer is Recommended?

[Ziggler]

1984 Morgan 323. Yanmar 3GMD 20 HP. OK, the question:

Which intake strainer is best? A 2-piece thru-hull replacing existing thru-hull? A cover-type that simply screws over existing thru-hull? How about the "Glass Reinforced Non-corrosive Marelon" that can be glassed in place on the outside of the hull? See pics. Let the opinions fly!

 

[thinwater]

I just screwed one of these over my AC intake, once I realized that I was clogging on minnows and jellies. That was 10 years ago. I literally drilled the holes (hand drill) while breath-holding and sealed them with butyl. Worked fine.

BTW, you REALLY want the slots OVER the opening so that you can poke straight through, right up the pipe. The usual hidden placement sucks once the barnackles move it. Don't know where they got that idea. That is why I used the separate strainer. Easier to clean. $9.29 at WM.

https://www.westmarine.com/buy/forespar--marelon-intake-scoop-strainers--P011_332_003_521?recordNum=4

 

[Maine Sail]

External Strainers - OMG!

 

[odaydokay]

A "South Bay Strainer" has worked for me since 1995. Has large surface area and the "cheese wedge" shape lets everything slip by it. Just keep those small holes open if you apply paint to it.

 

[thinwater]

External Strainers - OMG!

I get you.

• The water is warmer here. Diving is not a big deal.
• Jelly season here is something else.

On your advice, I tried without one first and clogged the pipe with jellies and minnows several times. Afterwards, no problems.

That said, the AC did have a low-flow alarm, and it went off a few times. Of course, on an AC strainer, that means the water is warm enough for a swim, in fact, it will feel good. On an engine intake strainer I can understand the conflict.

An important difference is that when AC runs when you may be pinned against a bulkhead, not moving, where the grass and jellies pile up. There is no shearing flow past the intake. When the engine is running you are probably moving, with good flow past the intake. So they are functionally different applications. (This assumes most sailors cannot run the AC underway, which is most commonly the case.)

 

[Rich Stidger]

Some people hate external strainers. I have a different opinion.

My OEM setup was a one piece strainer/thru-hull like in post # 1 above. I also had a couple other intake thru-hulls with no external strainer. After fighting with frequent clogs in all of the internal strainers, I replaced the one-piece strainer/thru-hull with a standard mushroom thru-hull. And I installed external strainers made by Groco pictured below. Since making that change, I get almost no debrix in my internal strainers. Like maybe one or two strands of grass in just one of the three intake strainers each year. In the Spring they are easy to clean out too. I'm sold.

 

[Rick486]

Some people hate external strainers. I have a different opinion.

My OEM setup was a one piece strainer/thru-hull like in post # 1 above. I also had a couple other intake thru-hulls with no external strainer. After fighting with frequent clogs in all of the internal strainers, I replaced the one-piece strainer/thru-hull with a standard mushroom thru-hull. And I installed external strainers made by Groco pictured below. Since making that change, I get almost no debrix in my internal strainers. Like maybe one or two strands of grass in just one of the three intake strainers each year. In the Spring they are easy to clean out too. I'm sold.

View attachment 186849View attachment 186850View attachment 186851

Beautiful fittings. I too have strainers on my inlets and have never had any problems.

 

[John T1594]

If you do go with a slotted strainer keep the slots facing aft. Keeps out much more debris.

 

[jssailem]

@Ziggler I bought an inline strainer and placed it inside the boat.
One like this.

The ARG 750 series.
I have been using it for 2 years and am very happy while sailing the Puget Sound. My boat is in the water year round. I drain the glass during winter and I keep some heat in the engine space. I have a note to refill the glass before I start the engine. I have had the similar plastic strainers, but the plastic tends to craze after a couple of years.

 

[JamesG161]

intake strainer is best?

My Bronze ones work great.

Bottom cleaning by diver said zero blockage.

Although I had my slot cleaner ready for him.

Slot cleaner is a bamboo cooking spatula with flat thin edge.
Jim...

 

[odaydokay]

Here is a South Bay Strainer in case you were wondering. Mine is a tad thicker at high end, but basically same principle.

 

[ifmdalvey]

I like the hinged version, have used one for 5 years and its the best investment i have made.

 

[RoyS]

I had both internal and external strainers on my engine raw water intake and my toilet intake. I removed my external strainers and immediately had jelly fish clogs. I put them back at the end of the season and will never go without them again. IMHO you need both internal and external strainers. One strand of eel grass passing through your external strainer can bring your manual pump toilet to a halt. One jellyfish in any intake can totally block the line.

 

[jssailem]

Roy there is a difficult answer for that problem. Sail in the PacificNW where the water is colder and the Jellyfish fewer.