e34-2 raw water intake screen

[phildogginit]

The raw water inlet on my e34-2 has a plastic grill on it. Attached is a photo of the three inlets next to the keel during a recent haul-out.

Has anyone removed the plastic screen to increase water flow?

 

[Christian Williams]

If you have an inside raw water strainer such as the Groco that screen can and probably should be removed.

 

[Frank Langer]

There is lots written, both pro and con, so some research may be helpful. I prefer the in line raw water filter, like the Groco in Christian's post above. The screen is effective and easy to clean. The screen on the outside hull does a better job of keeping weeds, small fish (yes, one got caught in my raw water seacock!), plastic bags, etc from entering the raw water intake, but they apparently get clogged more easily with weeds and debris on the outside. It might depend a bit on what debris you have in your local sailing area.
I'll be interested in what others recommend.
Frank

 

[bigd14]

External Strainers OMG - Marine How To

"RC My Engine is Overheating?" Over the years I have really grown to distrust and dislike external intake strainers of either the scoop type or the non directional (sailboat style) round type. The real danger in these devices comes when you have a blockage and can't get to the crud to clean it.

marinehowto.com

Here is an argument against them.

 

[Kenneth K]

I had the screen also, but mine was even more closed off than yours. Bottom paint may prevent growth (good) but it builds up on the screen (bad).


When I installed a raw water strainer, I cut about half of the cross-grids out of the thru-hull screen to increase the inlet size. I wanted to keep some of the screen for the reasons Frank mentioned.



My screen was plastic and I was able to cut it with an Exacto knife.

 

[Christian Williams]

And barnacles, too. A diver can scrub the outside of the external screen, but the calcium also grows inside.

 

[1911tex]

I try to keep my external screen clean...I have a GarminVirb waterproof video/still camera on a long mop stick that I dunk in the water from the finger pier and inspect the screen and all other inlets routinely. I also have a large sponge mop on extended stick that I can brush off anything that is creating a blockage..from the finger pier as well. In warmer months, I just jump in with a snorkel, mask and flippers, which my age, my family freaks out.

I can also use the camera out in the blue leaning over from the cockpit if the temp gauge begins to shows hot. I watch the temp gauge often when under power! I don't have an internal water strainer...which may be a good idea for little stuff, but always keep the external screen...there is more worry about @#$%^! flotsam debris blocking the inlet from suction then anything else in our lake; which to me makes an internal strainer secondary and useless if the inlet is blocked!

Just my observation......not necessarily valid.

 

[67rway]

Great discussion, having sucked river grass/weeds thru the raw water pump and into the heat exchanger...
Clear to see how it happened looking at the old thru-hull strainer. One of the new ones shown for comparison.

Seems ideal to have internal and external strainers.

 

[phildogginit]

I have a groco 500 strainer under the galley sink in addition to the external screen.

 

[footrope]

If you don't have a screen on the thru-hull, then add to your tool kit a stick of the correct diameter and length to push out the weeds or garbage that may someday block your engine intake thru-hull. That finally happened to us after a night in a weed-infested harbor. We had a 1/4" dowel from a mylar birthday balloon that we broke in half so it would fit under the galley sink and into the thru-hull.

I have never found any hard or soft growth up inside our thru-hulls. We live in cold water up here, maybe that is why.

We have an older internal Groco strainer that captures the eel grass and an occasional leaf. If that is a black plastic drain plug on the clear plastic strainer bowl, it will degrade and break someday if you tighten it too much or bump it too hard. On the older strainers it is threaded 5/16, 18 threads per inch. A standard 5/16-18 coarse thread screw fits perfectly. Add an o-ring, or an nut combined with an o-ring, and you have a permanent replacement for the broken plastic plug. Most of the older Groco strainer models that might be found on our boats seem to have that exact 5/16-18 plug according to Groco parts lists.