Thru hull strainer

FourPoints · Apr 21, 2011

I beleive you want the openings facing aft. This helps prevent then from getting clogged.

kloudie1 · Apr 21, 2011

Correct .. Openings facing aft

Stu Jackson · Apr 21, 2011

Get rid of it. Quickly.

http://www.ybw.com/forums/showthread.php?t=270894

Like parallel universes!!!

Merlin Clark · Apr 21, 2011

All U Get said:
Hi all,
After reading all the posts about strainers I decided to check mine. Four little screws were holding it on the bottom so I thought it would be easy to remove the cover. Didn't budge so I crawled under the shrink wrap and grabed the seacock. Several turns and half the valve was in my hand.

Back to the computer I found several styles of strainers and of couse I was going about it the wrong way. Got back inside the boat and with my wife holding the cover outside I was able to remove the other half of the seacock and the retaining nut and push the strainer assembly out. Good thing I did because there was hard epoxy and debris choking the opening to half its size. I do have a question, which way should it face? My pics are included. Picture 1 shows the strainer facing aft. The valve (plastic) is apart so I thought a little teflon grease would lube it. All looks really good so I'm going to remount it.
All U Get

=======

The first time I hauled my GS 41 it had one that looked just like that on the intake for the heat exchanger and inside the thing was an oyster of the same shape and almost (knock wood) the same size.
Didn't take much wrestling with myself to buy a new thru hull sans strainer.

Quick check:
1IN NPS BRZ THRU-HULL (EACH) SS-3895000TH1002 in stock $25.77
right here on SBO.

A diver will charge more than that to knock the barnys out of your old one.

Bad Obsession · Apr 21, 2011

I don't have one on mine....don't want one. I have a Catalina 30 Tall Rig and it came without the strainer.

The strainer would easily get clogged with slime, growth, and other things. That is why there is a strainer above the seacock.

Maine Sail · Apr 21, 2011

1- Slot strainers on sailboats should aim aft. Forward can waterlock your engine but backwards can cause undue vacuum. There is no ideal way for a slotted "scoop" strainer to be installed on a sailboat but a little vacuum is always better than filling your cylinders with water.

2- Round strainers, non-directional, are designed for sailboats and they have holes not slots and also tend to suck in much less eel grass.

3- Strainers should ideally be of the opening type..

4- There is no need for them with a proper intake diameter and internal strainer.

5- Read this: Why I Dislike External Strainers

Rick486 · Apr 22, 2011

I added strainers to both my engine intake and generator intake after two diving excursions in May at BI to free eel grass from the genset intake. Cold, cold water. The genset shut down for temp and true to Panda folklore, the impeller needed to be replaced.
Having said that, you must maintain the strainers. Each spring while I'm doing the bottom I inspect the strainers carefully and spray whatever spray paint I am using on the prop that year into the strainer. If I see anything growing in there I remove the four screws and clean it out. That has not been necessary after 4 years, however. The A/C inlet did in fact come with a strainer from Hunter but it was one of those one piece fittings, through hull and strainer. I replace that with a through hull and strainer. I know people who have had their main engine inlet clog with eel grass underway and render the engine useless until cleaned out. You must consider whether you want to take that risk. I abide by the rule that when I need the engine, I really need the engine and I want it ready, willing, and able.

Old Skool Neil · Apr 22, 2011

What's to prevent the strainer from becoming clogged on the outside of the hull? Whaddya do then? If I'm going to have a clog, I want it where I can get to it.

John T1594 · Apr 22, 2011

Aft facing strainer

I have owned two sailboats over the past 20 years (H30 & H340). Both boats came from the factory with no external strainer on the engine intake. The area where we sail has lots of eel grass and seaweed and I had a lot of overheating from a clogged engine intake and also had to frequently clean the sea strainer inside the boat. On both boats, I added an aft facing slotted strainer. Since then, I have (almost) never had my engine intake clogged with grass. I only open my internal sea strainer at the end of each season and usually find only a few pieces of grass.
When the boat is hauled in the winter, I probe the slotted stainer from the outside for barnacles and other debris and usually find nothing. I do paint he outside of the strainer with antifouling bottom paint and also spray a very little outdrive antifouling paint into the slots for full coverage.

Gary_H · Apr 22, 2011

If you are going to use a slotted external strainer then this might be an opportunity to change it out for one that hinges open for cleaning.

Roger Long · Apr 22, 2011

It took me about an hour today to swap mine out for a plain through hull. That included the time to add lag screws to hold the seacock to the backing block and keep it from rotating when I pulled the old strainer off with a pipe wrench. It's in a protected area so I don't think through bolts are necessary. The yard that put the strainer on left the seacock just held in place by the through hull.

BTW a crescent wrench handle inserted in the through hull with vice grips on it makes a good through hull wrench.

Thru hull strainer

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