Warning -- Plastic Bag in Cooling!

[Nicholson58]

2 inch inlet about 1/2 meter long into this visible strainer. I have the photo as documentation of my own quick fix when the one of the 1/4 inch bronze tie rods broke. Big strainer, short hose. The PO had previously removed the external strainer covers. I assume he was tired of diving to clear the debris.

I also have alarm/switches in my wet exhaust lines. I know the gen will automatically shut off but I've never tired the main. There is an analog gauge on the wet exhaust temp at the binnacle. I watch it carefully. We use it to tune the rpm-prop pitch against the engine to maximize power output.

[JPA Cate]

Accomplice,

This may not fit for you, but we have used the dinghy pump to blow out a plastic bag that got sucked up the engine intake. We were fortunate that there was enough breeze for me to jink around on the main, while Jim cleared the bag. I do not know if the dinghy pump (being high volume, low pressure) would remove a major clog event.

Ann

[accomplice]

Originally Posted by Ann T. Cate

Accomplice,

This may not fit for you, but we have used the dinghy pump to blow out a plastic bag that got sucked up the engine intake. We were fortunate that there was enough breeze for me to jink around on the main, while Jim cleared the bag. I do not know if the dinghy pump (being high volume, low pressure) would remove a major clog event.

Ann

Thanks, Ann. I carry an air compressor (2.8CFM@90PSI) for a hookah dive system -- probably higher pressure and volume than dinghy pump. If the dinghy pump worked for you then I imagine the air compressor might do too. How did Jim fit the dinghy pump to the intake line?

[accomplice]

Originally Posted by Dockhead

The fisherman sea strainer is attached directly to the through-hull. Pop the top off, open the valve, and you have direct access to the sea.

WATER STRAINER (FISHERMAN MODEL) 1.1/2"

My last boat had something like this, too. I can't imagine doing it another way.

Ahh... I have a seacock, approx 1meter hose, and a largish seachest with strainer that feeds the raw water needs of the aft half of the boat. I'd have to pull the hose off the seacock to get access to the thruhull.

Do you have one of those for your generator too?

Sent from my Nexus 7 using Cruisers Sailing Forum mobile app

[Dockhead]

Originally Posted by accomplice

Ahh... I have a seacock, approx 1meter hose, and a largish seachest with strainer that feeds the raw water needs of the aft half of the boat. I'd have to pull the hose off the seacock to get access to the thruhull.

Do you have one of those for your generator too?

Sent from my Nexus 7 using Cruisers Sailing Forum mobile app

Yes, two of them, identical. I toyed with the idea of making an interconnection so I could instantly switch over from one strainer to the other in case of a clog, but the realized it was more complication than it's worth. The beauty of these is that they are directly connected to the through-hull, so no clog can be out of reach, and it only takes a second.

[markpierce]

After checking water flow from the exhaust upon engine start, I periodically check the flow while underway. (Easy to do when exhaust is just outside the pilothouse door.)

[zboss]

Originally Posted by Dockhead

I would not want a strainer or sea-chest arrangement which did not allow me to poke a screwdriver through the through-hull to clear any blockage. I would not think that pressurized air would deal with every eventuality.

HA! About two months ago, the guy on the boat next to me in the mooring field came over and asked if I had a long screwdriver he could borrow. He was not getting any cooling water and was concerned that something had clogged the intake.

He eventually did as you say... he disconnected the hose and no water came out - viola! He then poked a screw driver into the through hull from the inside and water came flowing in. As soon as he removed the screwdriver the water would stop. He dove on the through hull and could find nothing blocking it.

Eventually, I saw him puttering back to my boat he handed a cup up and inside were to very large gobi's - they had made a home in his through hull.... anytime he would poke the screw driver in they would swim out. As soon as he removed it, they would swim back in. Eventually he was able to "fish" them out. Of course, they were dead..

[JPA Cate]

zboss,

Yeah, we've had fish jam in the toilet intake line, too. They get all mashed.

accomplice, Jim says, he closed off the intake, pulled the hose off and stuck the hose from the pump into it, started pumping and then opened the intake, and bluurp! it cleared. (The bluurp! is mine._)


G'night y'all.

Ann

[sailorboy1]

Originally Posted by Dockhead

What did I learn from this? Engine temperature is a poor guide to cooling water flow, at least on this engine, which must have a lot of thermal mass. I could have easily melted the exhaust.

The only time my intake strainer has clogged the signs we noticed were that the exhaust sounded louder and there seemed to be more smoke because of the lost water flow.

I plays to question things where sounds/smells/vibrations etc. aren't "normal" to you.

[captain58sailin]

Had a similar thing happen in the late 70s, melted a piston. Had an alarm, but wasn't loud enough to be heard. Hooked up a car horn after that.

[Coxswain]

Constant problem when sailing in Asia... never fails to get you at the most critical time as well! haha, got to love sailing!

[TeddyDiver]

Originally Posted by accomplice

TeddyDiver -- that works fine when the blockage occurs in the sea-chest -- as dockhead had. But in my situation this week the blockage was a large mass of debris on the outside of the hull.

A sea-chest is a structural part of the hull, an opening to the sea beneath. It has a grate to keep larger debris outside. Seacocks are installed on the sea-chest leading to separate strainer if the sea-chest doesn't have one.
A ships sea-chest has permanent grates preferably on both sides of the keel so that a blockage on one side doesn't cause problems.
In a boat it's easy to arrange a sea-chest which extends above the waterline so it can be opened for cleaning including a blockade outside the hull by removing the grate from inside while floating.
A strainer is not a sea-chest...

[valhalla360]

It was on our air/con but we put in a splitter, that a garden hose could be hooked up and backflush to get junk out (usually sea grass). I'm sure something similar could work on the engine cooling line hooked up to the wash down pump.

Always worked great.

[accomplice]

Originally Posted by valhalla360

It was on our air/con but we put in a splitter, that a garden hose could be hooked up and backflush to get junk out (usually sea grass). I'm sure something similar could work on the engine cooling line hooked up to the wash down pump.

Always worked great.

That was my first thought -- the washdown pump. Then I remembered that the washdown pump pulled its input from the same seachest / strainer -- which obviously wouldn't work. That's why I was thinking of using air -- just wasn't sure air pressure would do it. But based on what Ann/Jim did, it sounds like it ought to.

[Blue Stocking]

We have a problem with Sargassum weed around here. My engine intake is fitted with a "T" with the straight-thru vertical. Pump hose comes off the horizontal port and a capped standpipe to above the W/L from the other port. I can unscrew the cap and poke a 3 ft dowel back to the outside of the hull. Clears barnacles as well.