Raw water strainers

[ILikeRust]

The reasons I went with a RW strainer instead the former grate over the thru hull were (1) it's difficult if not impossible to prevent growth under the grate and inside the thru hull and (2) if something blocks the grate from the outside it's difficult to clear it.

...

Unrelated but when making the change from a grate type to an internal RW strainer I also increased the size of the thru-hull from 1/2" to 3/4".

+1

I had the exact same thoughts when converting from the factory-original external grate to an interior strainer - and I likewise used a larger through-hull while I was at it, to assure plenty of water flow.

[hanleyclifford]

Nothing wrong with an external grill style strainer so long as it is removable for painting. It is also beneficial to have an onboard system for backflushing the thru hull on the fly, as it were. I keep my raw water supply tee'd to the deck hose pump both for emergency cooling and flushing.

[ndutton]

Said here better than I ever could:

http://forums.sbo.sailboatowners.com/showthread.php?t=124964

[hanleyclifford]

Said here better than I ever could:
http://forums.sbo.sailboatowners.com...d.php?t=124964

Some good points there, Neil; but if ever you allow your external strainer to get filthified with paint or other junk like some of those pictures you don't deserve to have an engine in your boat. The grate should be removed, cleaned and painted at each haul out. BTW, never, never, never sail with engine shut down and raw water thru hull open.

[romantic comedy]

Ok Hanley, I will bite... Why?

I am sure that 99 percent of the fleet sails that way. I know that I do.

[Skywalker]

My boat had an old, bronze cheeze grater looking thing on its the only strainer.

It was permemtly attached to the bottom. I removed it when fairing the bottom, and to my surprise there was no growth inside at all. I figured that after nearly fifty years, that's pretty good.

I installed the clam shell, thru hull fitting in its place!

Now, it seems like a mistake!

I guess I have some time to sort this one out.

[ndutton]

The tipping point for me was a few years ago. I'd let the bottom paint go at least a year longer than I should have, maybe two years. Every payment to my diver included an apology note. One day I fired up the engine and immediately recognized the hollow echo of a dry exhaust. I shut her down, pulled the intake hose, opened the valve and nuthin'.

Next trip to the boat included SCUBA gear. From the outside of the hull with all thru-hull valves open I Roto-Rootered the thru-hulls with a long screwdriver. There was growth in all of them. Problem was the grate on the engine intake blocked my access. It was an integral part of the thru-hull, not removable.

Rodding it out from the inside, the grate also prevented a clean through shot to the outer reaches of the thru-hull. The best I could do was chip the growth into small enough pieces so they would flush into the hull with the water flow once it was restored. With an occluded 1/2" thru-hull they needed to be pretty small pieces.

Although quite a mess, it worked but I knew it was only a temporary fix. I vowed to get bottom paint inside the thru-hulls next time but then it dawned on me, there's that damned grate to deal with again. No way I'm getting any paint inside there with that thing in the way.

So, enough already. Haul out was scheduled, a new larger open thru-hull was installed, raw water strainer too as described in the earlier post. Now if it's ever necessary (it was on the Catalina trip due to kelp) I can clean the strainer inside the boat and can get more aggressive with a rooter, all with relative ease and no mess.

My old external strainer wasn't painted over like those horrible pictures in the link but the internal growth and blocked access were definitely issues.

[Mo]

Sounds reasonable to proceed as you did Neil, especially in an area where the water is warm and the boat stays in the water for long periods of time. Allot of the time boats are not cared for by their owners. Some clubs etc want to have their staff do the work and they may not be paying attention to detail as would the boat owner.

Mine usually spends 6 months in the water. I have a strainer and use ablative paint as well. When I paint the bottom I remove and paint both sides of the strainer. The ablative paint is pretty thin be this point as water is regularly being pulled through the strainer. I also put on a rubber glove and dip a finger in the paint and put a coat inside all thru hulls as far as my finger can reach...never had a problem with anything in any of them...then again the boat is out of the water every fall as well.

[ndutton]

Yeah, I haul every ~ 4 years. You snow belt guys might think Gee, how nice to haul out once in 4 years but the other side of the coin is things have to last: thru-hulls, valves, stuffing boxes, packing, shafts, bearings, etc.

It makes for tough business for the yards too. They're doing 1/4 the haulouts your yards perform annually. It has to hit the bottom line. You'd think the competition would be keen for the available work but strangely it isn't. For the most part the yards are cavalier and arrogant. Not all of 'em but still plenty.

I'll still take it over snow but in a way this might be a case of be careful what you wish for.

[Mo]

Yeah Neil, I hear you on the arrogance. A yard with a travel lift, a bit of space, a tad marketing...a guy could make a killing if they didn't get greedy. You need to know the clientele though and you need a strict set of rules.

I know a guy that had a spot to pull boats and he did "the pull for repairs and maintenance" thing for a while. It came to the point for him that it wasn't worth it and became a source of aggravation. Guys would put the boat in for repair and not get to the work in an expeditious manner. He'd have the work area blocked up with boats and no one working on them. Allot never paid up for the time they were there and he threw them back in the water just to be rid of them. It got old and he sold the land and the travel lift....currently there are plans to build condo's on his old place.

If you had one good "go to" guy on site; a good source for parts that clients could call on; tools that could be rented out etc there might be a market for it. One guys idea of hustle is not the same as the next and I think there-in lies much of the problem.

[toddster]

My boat was equipped with an external strainer similar to the first one in the picture link. At some point, most of the strainer screen had been removed, though. It was actually pretty thin and easily separated from the bronze of the main fitting. I peeled off the rest of it when I painted. It might have been rodded out from the inside or cut from the outside, or who knows.
Anyhow, amputation could be a viable option at need.

[edwardc]

I've had to run a piece of rebar down through the raw water intake a few times to evict sea life. (external strainer)

How do you do this when the boat is in the water? Close the ball valve, remove the intake hose, attach a clear plastic tube, and support it in an upright manner. Open the ball valve and cut the tube off just above the water line and ream away through the ball valve. This works quite well. At least it does for me.

I remember reading in the forum where someone couldn't be bothered with all this. They blasted the fire extinguisher through the intake and cleared it that way!

TRUE GRIT

Instead of a fire extinguisher, you can use one of those compressed-air-in-a-can air horns. Cheaper than an extinguisher, no powder mess, and it's still usable for its original purpose afterwards! I've used this to clear my cockpit scuppers before.

And of course, you guys with scuba tanks onboard are no strangers to MacGuyver'd uses of compressed air!

[toddster]

Yeah Neil, I hear you on the arrogance. A yard with a travel lift, a bit of space, a tad marketing...a guy could make a killing if they didn't get greedy. You need to know the clientele though and you need a strict set of rules.

I know a guy that had a spot to pull boats and he did "the pull for repairs and maintenance" thing for a while. It came to the point for him that it wasn't worth it and became a source of aggravation. Guys would put the boat in for repair and not get to the work in an expeditious manner. He'd have the work area blocked up with boats and no one working on them. Allot never paid up for the time they were there and he threw them back in the water just to be rid of them. It got old and he sold the land and the travel lift....currently there are plans to build condo's on his old place.

If you had one good "go to" guy on site; a good source for parts that clients could call on; tools that could be rented out etc there might be a market for it. One guys idea of hustle is not the same as the next and I think there-in lies much of the problem.

Bit of a thread hijack here, but in my limited experience (2x) the yard guys clearly think that messing with a 40 year old DIY boat is not worth their time. Even though both places milked the job a bit. It looks to me like their business models must call for making a lot more $$ per boat.

[lat 64]

Ok Hanley, I will bite... Why?

I am sure that 99 percent of the fleet sails that way. I know that I do.

I'm guessing Hanley's getting water flowing up from that scoop-shaped intake grate and flooding the manifold on a heeling boat.

Just a guess.
Each boat is different.

[ndutton]

It looks to me like their business models must call for making a lot more $$ per boat.

What the short-sighted idiots don't understand is if they take good care of me, a lowly do-it-ALL-yourselfer with a 36 year old boat I'll tell everyone I see how pleased I was with the service. AND I'll be back.

The opposite is true too.

Sorry for the hijack