Raw Water Strainer??

[rpell1@msn.com]

Hi all,

My '91 Cat.30 is still on the hard, waiting patiently to get wet again. After finishing all the blister repairs, bottom painting, washing and waxing, I noticed something missing. On every other boat I've seen, there was always a bronze strainer attached to the outside of the hull covering the raw water inlet.

Since there was no evidence of one ever having been attached, (no screw holes or "imprint" in the paint), I am wondering if maybe this boat never had one to begin with.

Has anyone else experienced this?

Thanks,

 

[Roger Long]

Don't worry. Maine Sail should be along shortly to tell you that you are lucky and don't have to go to the trouble of removing one. Most boats have them but he makes a good case that they shouldn't.

You do have a strainer inside I hope.

 

[rpell1@msn.com]

Absolutely!! Thanks.

 

[Bad Obsession]

My boat doesn't have one. I must say that a lot of the Catalina 30s that I have seen haven't had them.

 

[Old Skool Neil]

My boat had the external strainer and at last haulout I got rid of it. Prior to haulout I let the bottom paint go way too long. My diver was keeping up pretty well but I was getting some hard growth inside the thru-hulls. The first indication was no water to the engine. I pulled the intake hose and opened the valve, nuthin'.

I tried rodding the growth out from inside the boat and it worked somewhat. I was able to restore flow but the external grate was in the way. Following that I donned scuba gear, screwdriver in hand and roto-rooted all the thru-hulls from the outside. With the grate on the engine intake thru-hull, there was no way to get in there and clean it out.

At haulout I replaced the original grated thru-hull with a larger open type and added a raw water strainer in the engine compartment. With the larger thru-hull I could get a generous amount of bottom paint up inside there too, impossible to do with an external strainer thru-hull.

 

[Stu Jackson]

Neil's right, forget it. Just another place to "grow" a blockage.

 

[Old Skool Neil]

Wanted to reinforce Roger's last sentence in post #2:

You do have a strainer inside I hope.

 

[Anonymous 121765]

Ralph,

I've been reading this thread and aware of associated problems with the the-hull/strainer and can tell you I experience no problems with clogging and I am located in a dead end lagoon.

I originally had issues with clogging and fixed it in this manner. I have a vertically hard-piped tube coming off my thru-hull valve, At the top (which is above the waterline), I have installed a threaded tee fitting. Picture a tee in the vertical with the branch connection coming off the side (horizontally). I have a pipe plug in the top of the tee and the branch connection runs to my strainer.

A few times a year from inside the boat, I unscrew the plug, open the valve and have a rod that I can pass down thru this pipe, thru the ball valve and roto-root the thru hull fitting. I made a circular end fitting on the rod (with matching diameter) for scraping any growth that might form. Any break away buildup, I pump the rod up and down to flush it back out thru the strainer clam.

They also make a marlon type of clam & thru-hull fitting, and this will not allow any growth. I think on my next haulout, I may add this.

Where my boat is located, we have a penchant for fast slime & barnacle growth, but using this configuration, have never had a problem with water blockage. I needed to reposition my strainer some time back and decided to go with this design as my strainer clam is the non-removable type with no cleaning hatch built in.

As for the hull strainer clam, every time I check my inboard strainer basket, it's pretty grass free. In my area, there is always a grass line or Sargassum to sail thru.

Just wanting to add some useful info pal..........

CR

 

[SailingWebGuy]

I read this thread yesterday. Today, I had my head inside the engine compartment and happened to peak straight down the strainer thru hull (hose was off and boat is on the hard). I wondered.. "Maybe I can paint the inside of the strainer from up here." So I grabbed some tape. Taped up the grate from the outside. Then I poured a few spoonfuls of anti fouling into the thru hull from the inside of the boat. I filled it enough so that the clam portion of the strainer on the outside of the boat filled up. I then let it sit for a few minutes while I gathered up some rags and a little disposable container. I removed the tape and cleaned up all the paint that ran out. Hopefully I flooded that clam part enough to cover most of the inside.

 

[rpell1@msn.com]

Good info. I have almost the identical set-up. The Roto-rooter arrangement is a stroke of genius. I am not patronizing.....I like it.

Thank you much.

 

[Anonymous 121765]

Ralph,

As I mentioned before, there are a few clams with opening clean out sections. I do know that Marlon doesn't allow growth, and is advertised as pretty strong. All my thru-hull valves are marlon, and if you should see one, they make a heavy-duty body (about 1 1/2 times the size of metal valves). I will probably go with Marlon @ next haulout.

I have a monthly scuba clean guy and/or maybe it's the water I sit in, but have never had inlet growth problems. I do need the clam as I've said we sail thru alot of grass.

From what I've read there are many options that would work.

CR

 

[Old Skool Neil]

One of the strategies of going with an open thru-hull and raw water strainer in the engine compartment is the ability to clean it out easily and not have a clog outside the hull. The strainer basket is also finer mesh than an external grate.

 

[Anonymous 121765]

Neil,
When all is said and done, alot of it may be due to the area you sail in. Some skippers I know without clams are constantly cleaning their strainers of grass. It may also be a question of thru hull location on the boat. I don't know if Catalina 30's have the location the same from year to year.

If you have no problem with your setup, your far ahead of the game.

CR

 

[jrowan]

When I hauled out my last boat after I bought it (it had been in the water for over 3 years) & was way overdue ( no bottom paint left on it) there was literally a clam shell glued onto the raw water strainer intake. Somehow the Yanmar engine still got raw water, which was miraculous - I think the clam was a natural water fliter!