Sea Strainer Disaster Averted

[Max Simmons]

Recently I replaced the hoses on the raw water side of the engines, and while doing this, pulled the sea strainers, disassembled, cleaned them up and replaced the gaskets. After getting everything back together, opened up thru-hulls and checked for leaks. The Port side had a small drip coming from the bottom, where the clear cylinder beds into the new rubber gasket. I snugged down the tie rod nut about 1/2 a turn and it stopped. Ran engines for a bit to make sure all was well, water was flowing, no leakage, all is good. I shut everything down and closed the thru-hulls and headed home. A few days later, I'm on the boat, headed out for a short cruise with a friend. Drop down in the engine room and open up thru-hulls. Water is pouring out of the Port strainer, WTH? Close thu-hull and investigate. Turns out one of the tie rods snapped sometime while I was away, which in turn allowed raw water to dump out the bottom straight into the bilge. I pulled the strainer and replaced the rods.
My takeaway from this is just common sense reminder to always shut the thru-hulls when away from the boat. I had typically done this only when away for long periods of time. Also, thoroughly inspect the sea strainer assemblies. There are many weak links here, any one of them failing could be a potential disaster.

 

[AlaskaProf]

Thanks! A vulnerability I never think about.

 

[firehoser75]

Personally, I close my through hulls every time I shut down the engine, just in case. To drastically reduce any problems with "forgetting to open" before running, I place a small card right beside the start key/button that states, "thru hull closed". Between that card being very visible beside the start key and the fact that this is now "habit", I have never had an issue with this.

I also have a water flow alarm installed in the raw water line between the strainer and the pump that should alarm instantly if the thru hull were left closed.
To me, this (set up and procedure) makes great sense. It almost eliminates the possibility of leaks such as could have happened to you if the thru hull had been left open, and it exercises the thru hull regularly so it will not get stuck in one position.
Mind you, I have easy access to the thru hull, so that makes it easy.

 

[FF]

I have seen boats where the bronze tapered plug sea cock was kept in such good condition that a set of cables (43 series) and repurposed engine control handles worked for remote control.

The boat was commercial so the fuel tank also had cable operated valves operated from outside.

We spend thousands on insurance which only pays after a disaster , cables are cheap!

 

[CaptTom]

I've been known to hang the keys on the valve handle. No way to start the engines without going down there.

 

[ksanders]

Thinking about the repair for this, and or spare parts to have onboard.

On my boat I have two 2” Perko 0493 strainers.

The bolts in your photo for my strainers are something over $200 for a set of four. OUCH!!!

I just looked and you can get a 3’ piece of threaded bronze rod 5/16 dia at Jamestown distributors for $47, and less than a third of that price for SS threaded rod.

 

[Insequent]

Recently I replaced the hoses on the raw water side of the engines, and while doing this, pulled the sea strainers, disassembled, cleaned them up and replaced the gaskets. After getting everything back together, opened up thru-hulls and checked for leaks. The Port side had a small drip coming from the bottom, where the clear cylinder beds into the new rubber gasket. I snugged down the tie rod nut about 1/2 a turn and it stopped. Ran engines for a bit to make sure all was well, water was flowing, no leakage, all is good. I shut everything down and closed the thru-hulls and headed home. A few days later, I'm on the boat, headed out for a short cruise with a friend. Drop down in the engine room and open up thru-hulls. Water is pouring out of the Port strainer, WTH? Close thu-hull and investigate. Turns out one of the tie rods snapped sometime while I was away, which in turn allowed raw water to dump out the bottom straight into the bilge. I pulled the strainer and replaced the rods.
My takeaway from this is just common sense reminder to always shut the thru-hulls when away from the boat. I had typically done this only when away for long periods of time. Also, thoroughly inspect the sea strainer assemblies. There are many weak links here, any one of them failing could be a potential disaster.

A near miss for sure! I had that type of sea strainer on my boat initially. Neither the PO or myself were in the habit of closing the seacocks. But guys at the yard during my refit warned me about the known failure issue. So I ditched them in favour of better designed units.