Good raw water strainers

[Snowpetrel]

Next part of my engine install is the raw water feed to the impeller pump. What feedback is there on different strainer units. The forespar marelon one looks nice, but the stainless bowl and centre stud seem like potential corrosion issues? The Vetus ones look ok, but are cheap plastic, and a similar cheaper version I've used is very hard to undo once done up tight enough to stop air leaks. What do you guys have and how well does it work?

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[Panope]

SnowP, I chose the Vetus strainer because the intake nipple is located on the bottom of the unit. This allowed me to "stack" the standpipe, shut-off valve and strainer in a strait, vertical line - thus allowing easy blockage clearing with a rod (with valve open and strainer lid removed). Valve and strainer are mounted above waterline.

This strainer does "feel" a little flimsy. However, it has performed perfectly with no air-leakage and the lid has always come off by hand. Actually, it takes two hands so it is important to locate it somewhere with good access and solid mounting.

The "see through lid" is nice for verifying the flow of water.

In Panope's previous life, she had a normal, bronze strainer (below waterline) connected to an aluminum sea-cock via rubber hose. That strainer worked fine but did turn various shades of green and was always kind of a mess. It did not cause any corrosion of the hull (aluminum).

My primary reason for switching to the new set-up was for the aformentioned ability to clear blockages easily and without the little saltwater geyser.

Steve

[Snowpetrel]

Thanks Steve, a beautifully installed setup as always. I am to afraid to post any pictures of the mess of pipes in the fuel and water systems that I have so far, but in time I aspire to your sort of logical and neat layout.

Good to hear the vetus is working out well. I plan to mount mine in a similar way. But I first need to install the seacock under the final location. At the moment I am using the old 3/4 seacock and convuluted aluminium pipework under the floor that needs to be removed but will do until I next haul.

On another note has anyone had issues with air getting into the system while sailing. Had some nasty issues on one flat floored boat, I can only guess that small bubbles in the salt water got pushed under the hull while sailing and ended up in the highest point , being the filter. It only took an hour before the system completely filled with air. It didnt happen at anchor. I am guessing that a deep v hull like panope would encourage the air to rise to the surface before it could go into the intake? Cheers

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[Panope]

I have no evidence of any air entering the raw water intake while underway. However, if some air were to enter the system, I believe it would quickly "self purge". Whenever I remove the lid on Panope's strainer, all the water runs out of strainer and the standpipe (when I open the valve). Upon reassembly, I have never bothered to "pre-fill" the bowl with water. I just start the engine and the air is quickly sucked on through the system.

Note: If the raw water system is COMPLETELY dry, Prior to staring the engine I dump a little water down the hose leading to the pump so as not to burn/melt the impeller.

Steve

[Terra Nova]

Pan--you should double clamp all connections below the waterline using non-perforated clamps.

OP--Groco sea strainers seem to be the industry standard.

[Panope]

Originally Posted by Terra Nova

Pan--you should double clamp all connections below the waterline using non-perforated clamps.

Agreed, and they are.

The single clamps in the pictures are all above waterline and their failure actually adds a tiny margin of safety as that would create an effective siphon break.

Steve

[Snowpetrel]

Ha, Standpipes are great, very reassuring to have all the fittings above the waterline.

The boat which got air in the system didn't self bleed. Very annoying and dangerous with where we were sailing. Probably in retrospect the impeller pump was worn, and a new one would have been more self priming. But it was still weird how the bilge mounted strainer filled with air when sailing. So did the PSS stern seal, which didn't have a bleed line, so that had to burped as well. Not confidence inspiring!

Those groco ones look nice, but probably way out of my budget by the time I import one into australia. Also trying to avoid bronze on my alloy boat, not that it's a big issue in this case, and I don't really trust stainless in saltwater.

So one plus for the vetus, anybody got a forespar marelon one like this? it will cost me 3 times what a budget one will...
Just reading the specs, forespar recommend 12 inches above the waterline vs vetus 6 inches. a point in favor of vetus...

Then there is the budget option for $54 aud. I've used one and it works but feels flimsy when you need to force the lid off, with the bracket twisting. But it hasn't broken yet.

[JPA Cate]

Ben,

Jim has a kit for making his own O rings. Last year, he made one for the Vetus water strainer, which afaik is original to the boat, 25 yrs. old. It no longer leaks, but, we had fussed a bit with it (I made a think gasket to raise the original sealing ring a bit, but the thrumscrew also has to seal, and so on.) I guess the point is, that although they do eventually start to leak, I think fixing it is well within your capabilities.

Ann

[Chuck Hawley]

I have a few thoughts. I have the same Vetus strainer, and while it has been difficult to get the lid off on occasion, I am not worried about its construction. I use some silicone grease on the threads and o-ring, and it seals easily.

Second, I've just returned from a nice charter in the BVIs on a relatively new Moorings 4800 cat. Our generator packed it in after two days, and I suspected that the floating weed (Sargasso Seaweed?) had clogged the strainer. Once I found it, (deep in the bowels of the port ama), I pulled out a handful of junk from the Jabsco plastic strainer. What I didn't notice, but should have, is that despite leaving the seacock open for this operation, the water didn't gush in. It gurgled, but it didn't gush.

Later, when the mechanics from Moorings showed up, they bet me that it was a clogged seacock, not a clogged filter. Sure enough, when the removed the Marelon seacock, it was stuffed with weed. Pretty interesting to remove the one item between you and sinking, but they were able to do it without much drama.

My point is: pick a good strainer, but make sure you can get to your through hull, which serves as the first "strainer" in the system whether we want to or not!

Chuck

[Snowpetrel]

Thanks for the extra feedback, Ann and Chuck on the Vetus strainer. Sounds like while not perfect (get tight and need lubrication) they seem to last. Might have to order one. I ran the engine today for half an hour and saw a small tadpole type thing go through the impeller pump... At the moment I have a grating over the inlet, but that is all, and the clear reinforced pipes show everything going through the system.

[Kijit]

We have the same Vetus strainer and have had no issues with it.

[Triumphant]

Originally Posted by Kijit

We have the same Vetus strainer and have had no issues with it.

+1 for Vetus, Mine was installed in 1990

in fact I have 2 Vetus strainers,

1 before the sea water pump to catch weed etc and 1 after the pump to catch any pump impeller blades before they get into the heat exchanger

[noelex 77]

The Vetus is a good product. No corrosion and it is well made. Plastic worries me, but it can be installed in such a way that it cannot flood the boat even it it fails.

The lid can get tight. Vetus sell a special plastic wrench to remove the lid, but I made my own from some wood scraps.