Sea water strainer Install

mogul11 · #1 (**permalink**) 03-25-2003

I have a Catalina 36 mkII and they do not install sea water strainers over their engine thru-hulls. I plan on doing this before splash this spring. Questions! How is this stainer screwed to the hull and still eliminating water from seeping into the F/G? Is their a trick to this since bedding compound doesn''t seem to give me a warm fuzzy it will keep water from wicking into the F/G. Thanks

Denr · #2 (**permalink**) 03-25-2003

Yeah drill four 1/2 diameter holes in the bottom of the hull and use hose washers to seal the hole. NOT! You''re not supposed to attach the damn thing to the hull! The strainer will most likely be a glass or plastic container with a metal mesh basket inside. It should be mounted to a wooden vertical surface in or around the engine room, preferably above the water line with a reinforce hose between the strainer and the seacock.

Big shame on Catalina for not equipping a 36 foot boat without a strainer, I guess you get what you pay for!

mogul11 · #3 (**permalink**) 03-25-2003

I am not talking about the water filtration system with the screen which is on the boat. What I am asking about is the Bronze strainer that is attached to the hull over the thru hull so weeds and marine growth can not make it into the hose and impede water flow. Every boat I have owned in the past had this strainer, I guess Catalina doesn''t use them since I have not seen any boats with them.

Denr · #4 (**permalink**) 03-25-2003

I misunderstood your question; my exterior strainer is a bronze single piece unit that is essentially the thru hull (not part of the seacock) check out the Groco web sight.

tsenator · #5 (**permalink**) 03-25-2003

Mogul,

Are you sure you need an external screen? I know you have the internal water filter basket (either a Groco, Forepar, etc basket).

I know most people that race wouldn''t want another "protrusion" sticking out of your hull. I have gone dozens of years without an external screen, and I know most boats around here don''t have one. Are you running into problems where your boat is located? Is there a lot of eel grass or something clogging your intake?

If you really wanted to put one on, you already have the thru hull so you can just add the Groco ones I have seen that are 2 pieces. Its a slotted strainer with mounting ring. Take a look. ( http://www.groco.net/catalogpage.cgi?id=590 )

What you could do is just clean the bottom paint down to the gell coat and then just attach the ring to the hull with 5200 and secure the mounting ring some how while the 5200 sets up (This stuff is pretty sticky tenacious stuff). Don''t forget to tape over the screw holes that will be used to attach the slotted strainer, you don''t want them filled with 5200.

Paint the whole thing with bottom paint then all you''d have to do is attach the slotted strainer with the 4 or 5 screws.

rheaton · #6 (**permalink**) 05-11-2009

Folks, I know this is an old thread but, I have a question along the same line, which I don think was answered here. I have a 1978 Catalina 30. It has a strainer type thru hull fitting. It is a rectangle shaped appendage on the hull bottom. The wooden backing plate inside the boat is rotten and the system is leaking. I wish to replace the entire system with a mushroom style thru hull, with an internal Greco water strainer.

My question is, has anyone taken off one of these external strainers. I would like to get some tips on this. I did remove two small screws on the outside, and one large nut attached to the thru-hull pipe on the inside bilge side.

Any tips or information on this would be greatly appreciated.

Thanks,
Russ

sailingdog · #7 (**permalink**) 05-11-2009

A photo of the external side of the strainer through-hull would help. Are you talking about one of these:

rheaton · #8 (**permalink**) 05-12-2009

My strainer is not like that one.

Mine is rectangle shaped. It's about 6" long and 3" wide, 1.5" deep at aft end, and 1" deep towards bow. Many holes about 1mm forming the strainer. I will take a picture this Thursday.

Thanks much.

Take care,
Russ

jjablonowski · #9 (**permalink**) 05-12-2009

I have a strainer on my (older) Catalina, and it looks like the photo posted by SD, and I like it. Keeps out seaweed, plastic bags, etc.

But I was talking with a yard-mate who rigged his Starwind differently, for ease of maintenance. His raw-water intake is a plain through-hull and ball valve, and it is fitted with a pipe pointing straight up that terminates above the waterline.

That pipe ends in a T-fitting mounted sideways. Raw water is piped to the mesh strainer and pump from the T's "bottom." The upper end of the T is capped.

Periodically, he removes the cap, opens the ball valve to the through-hull, and pokes out barnacles and other crud with a long stick.