Raw water strainer - a near boat-sinker

[derfy]

On a recent cold night on the ICW...


Just after opening the seacock, the old bronze Perko raw strainer lid popped open and sea water sprayed into the engine room. I immediately shut the seacock, and noticed one of the two pivoting "dog bolts", that retain the strainer lid, lying sideways and not holding down the lid.



The bolt had cracked at the pivot hole and failed the instant that water pressure was applied. See pic...


Sometimes you have to be lucky...



1) This strainer is for the A/C, not the engine. After clearing all my strainers the day before, I shut off the seacock before leaving the dock. Lucky me!

Had it been the engine, or had I been lazy, the seacock would have been left open all day while we were topside.

2) It failed immediately when I opened the seacock. It could have easily waited until the middle of the night when all were asleep, or days later when one was aboard. Whew....Lucky me!



3) I was able to find a suitable jury rig - see pic of C-clamp. This allowed us to use the A/C heater mode and to stay warm on a very cold night in Coinjock. I admit I woke a few times to check it during the night. It stayed put. Lucky me!



What I did right...


1) Kept the seacocks closed on all thru-hulls that are not in use!!!



I have learned this from past experience, and it paid off here.



2) Gently but firmly tightening the wing nuts after cleaning the strainer. I did not over-strain the bolt.



3) Tested raw water flow - I ran the A/C and checked that water was being pumped, before shutting off the seacock.



What I did wrong...


1) Not noticing the obvious - on a 30-year-old boat, an old rusty raw water strainer just ought to be replaced. Duh...

I put new bolts on, but a new strainer is the right answer. I have already replaced a similar one on the engine.



2) Trusting a survey - yes, some things were found and remedied, but he missed this one. I really thought a survey would show any obvious boat-sinkers. Nope...



3) Not looking into the engine room and bilge often enough when underway. Sailing and piloting is so much fun, and engines are noisy, smelly, and complicated. But...bad stuff can be avoided.





Maybe there is something else I did wrong or right? Comments, please!



Hope this helps prevent some future disaster.

[stimpsonjcat]

C-clamps...you can never have enough.

Have had several instances where a c-clamp and two pieces of flat wood or metal got used to seal a busted hose.

[tkeithlu]

Scary experience, and you came through it wonderfully.

Something to think about. I considered the possibility of similar events, and not being able to get to the main seacock in the engine room in time. My solution was to shift the seacock arm such that "open" is horizontal and "closed" is vertical, the reverse of standard practice. I then ran a wire from the arm up into the main salon above the engine room, and capped it with a small wooden knob. Pulling the knob closes the seacock without having to get to it.

[tkeithlu]

"C-clamps...you can never have enough."

Vise Grips, you can never have enough.

Vise Grip hose clamp, one is a damned good investment.

Keep them clamped to a frame member as close to a future disaster as possible.

[Mr O]

If your boat has room to install strainers above the waterline, consider it. This eliminates the chance of flooding your boat from a failed strainer. Also, you will be able to clean the screens without spilling a drop as there is no pressure. In fact, there is a slight vacuum that can be released by opening the seacock. Both engine and genset strainers are mounted above the waterline on my boat and they are a breeze to maintain. Not the case with the deckwash and watermaker strainers which are small bronze ones with plastic screw-on lid which are mounted low. They are a pain to clean and I would like to replace them with new ones mounted up higher. Thx for bringing this up. It is one of the most important systems to maintain on our boats to keep them afloat!

[Shrew]

I can guess as this happened to me this fall. My strainer was about 20 years old and the lid had a cork gasket. The gasket was heavily compressed and hard. The bronze wingnuts showed signs that it had been weeping for a while and two of the tabs were already bent, indicating someone putting a decent amount of force to close the seacock lid.

I started turning the wing nuts until the lid stopped weeping, then 'sproink' (well ok...."Bang") the bolt sheared exactly the same way yours did.

My guess is someone overtighting the wingnut and compromised your bolt as well, with the same results.

[Boatyarddog]

Originally Posted by derfy

On a recent cold night on the ICW...


Just after opening the seacock, the old bronze Perko raw strainer lid popped open and sea water sprayed into the engine room. I immediately shut the seacock, and noticed one of the two pivoting "dog bolts", that retain the strainer lid, lying sideways and not holding down the lid.



The bolt had cracked at the pivot hole and failed the instant that water pressure was applied. See pic...


Sometimes you have to be lucky...



1) This strainer is for the A/C, not the engine. After clearing all my strainers the day before, I shut off the seacock before leaving the dock. Lucky me!

Had it been the engine, or had I been lazy, the seacock would have been left open all day while we were topside.

2) It failed immediately when I opened the seacock. It could have easily waited until the middle of the night when all were asleep, or days later when one was aboard. Whew....Lucky me!



3) I was able to find a suitable jury rig - see pic of C-clamp. This allowed us to use the A/C heater mode and to stay warm on a very cold night in Coinjock. I admit I woke a few times to check it during the night. It stayed put. Lucky me!



What I did right...


1) Kept the seacocks closed on all thru-hulls that are not in use!!!



I have learned this from past experience, and it paid off here.



2) Gently but firmly tightening the wing nuts after cleaning the strainer. I did not over-strain the bolt.



3) Tested raw water flow - I ran the A/C and checked that water was being pumped, before shutting off the seacock.



What I did wrong...


1) Not noticing the obvious - on a 30-year-old boat, an old rusty raw water strainer just ought to be replaced. Duh...

I put new bolts on, but a new strainer is the right answer. I have already replaced a similar one on the engine.



2) Trusting a survey - yes, some things were found and remedied, but he missed this one. I really thought a survey would show any obvious boat-sinkers. Nope...



3) Not looking into the engine room and bilge often enough when underway. Sailing and piloting is so much fun, and engines are noisy, smelly, and complicated. But...bad stuff can be avoided.





Maybe there is something else I did wrong or right? Comments, please!



Hope this helps prevent some future disaster.

It would be wise to inspect more around your strainer area.

For instance, the hoses, connected to this strainer are compressed at the stainless clamps, as well those hoses are attached to what looks like Threaded nipples?
These areas are notorious for unseen corrosion.
As those hoses are not connected to hose barbs and can get corrosion under the fitting and eat away at the connection, these could be possible breakage areas, as well any over compressed hose is already weakened enough to be subject to breakage.
Unseen corrosion is usually apparent in disassembling other corroded fittings that are noticed.
A lot of corrosion starts internally and works its way out, weakening the fitting till it leaks or breaks.
Thus, the need for occasionally inspecting and applying lanocote or anti corrosion sprays,ect.
I'd check those hoses for cracking as salt can build up in them, the outer layer may have checks or cracks or be brittle.
There are so many possibilities.
Cheers,
SV Cloud Duster

[maine50]

I can't stress enough how important a BILGE ALARM is. It's the fall back- save your boat solution. Once something happens and the water gets above the floor boards your chance of saving the boat diminishes.

[MV Wanderlust]

Wow! Close call for you and a great lesson for all of us. Thanks for sharing. Quick thinking on your part prevented a disaster.

[Boatyarddog]

Originally Posted by derfy

On a recent cold night on the ICW...


Just after opening the seacock, the old bronze Perko raw strainer lid popped open and sea water sprayed into the engine room. I immediately shut the seacock, and noticed one of the two pivoting "dog bolts", that retain the strainer lid, lying sideways and not holding down the lid.



The bolt had cracked at the pivot hole and failed the instant that water pressure was applied. See pic...


Sometimes you have to be lucky...



1) This strainer is for the A/C, not the engine. After clearing all my strainers the day before, I shut off the seacock before leaving the dock. Lucky me!

Had it been the engine, or had I been lazy, the seacock would have been left open all day while we were topside.

2) It failed immediately when I opened the seacock. It could have easily waited until the middle of the night when all were asleep, or days later when one was aboard. Whew....Lucky me!



3) I was able to find a suitable jury rig - see pic of C-clamp. This allowed us to use the A/C heater mode and to stay warm on a very cold night in Coinjock. I admit I woke a few times to check it during the night. It stayed put. Lucky me!



What I did right...


1) Kept the seacocks closed on all thru-hulls that are not in use!!!



I have learned this from past experience, and it paid off here.



2) Gently but firmly tightening the wing nuts after cleaning the strainer. I did not over-strain the bolt.



3) Tested raw water flow - I ran the A/C and checked that water was being pumped, before shutting off the seacock.



What I did wrong...


1) Not noticing the obvious - on a 30-year-old boat, an old rusty raw water strainer just ought to be replaced. Duh...

I put new bolts on, but a new strainer is the right answer. I have already replaced a similar one on the engine.



2) Trusting a survey - yes, some things were found and remedied, but he missed this one. I really thought a survey would show any obvious boat-sinkers. Nope...



3) Not looking into the engine room and bilge often enough when underway. Sailing and piloting is so much fun, and engines are noisy, smelly, and complicated. But...bad stuff can be avoided.





Maybe there is something else I did wrong or right? Comments, please!



Hope this helps prevent some future disaster.

Great pictures by the Way!
Thanks for that!

I do see quite a few items you'd be wise to update.
Hoses, clamps, even the bonding wire attachments look ready for some TLC.
Welcome to maintainance.
SV Cloud Duster

[mainship 34]

Originally Posted by derfy

On a recent cold night on the ICW...


Just after opening the seacock, the old bronze Perko raw strainer lid popped open and sea water sprayed into the engine room. I immediately shut the seacock, and noticed one of the two pivoting "dog bolts", that retain the strainer lid, lying sideways and not holding down the lid.



The bolt had cracked at the pivot hole and failed the instant that water pressure was applied. See pic...


Sometimes you have to be lucky...



1) This strainer is for the A/C, not the engine. After clearing all my strainers the day before, I shut off the seacock before leaving the dock. Lucky me!

Had it been the engine, or had I been lazy, the seacock would have been left open all day while we were topside.

2) It failed immediately when I opened the seacock. It could have easily waited until the middle of the night when all were asleep, or days later when one was aboard. Whew....Lucky me!



3) I was able to find a suitable jury rig - see pic of C-clamp. This allowed us to use the A/C heater mode and to stay warm on a very cold night in Coinjock. I admit I woke a few times to check it during the night. It stayed put. Lucky me!



What I did right...


1) Kept the seacocks closed on all thru-hulls that are not in use!!!



I have learned this from past experience, and it paid off here.



2) Gently but firmly tightening the wing nuts after cleaning the strainer. I did not over-strain the bolt.



3) Tested raw water flow - I ran the A/C and checked that water was being pumped, before shutting off the seacock.



What I did wrong...


1) Not noticing the obvious - on a 30-year-old boat, an old rusty raw water strainer just ought to be replaced. Duh...

I put new bolts on, but a new strainer is the right answer. I have already replaced a similar one on the engine.



2) Trusting a survey - yes, some things were found and remedied, but he missed this one. I really thought a survey would show any obvious boat-sinkers. Nope...



3) Not looking into the engine room and bilge often enough when underway. Sailing and piloting is so much fun, and engines are noisy, smelly, and complicated. But...bad stuff can be avoided.





Maybe there is something else I did wrong or right? Comments, please!



Hope this helps prevent some future disaster.

Thank you very much for sharing and a great lesson to me!

[captrod]

I made the same item into a key ring. Had the boat on the hard for two weeks. Did a great bottom job. Cleaned strainers, put cover back on over rear of engine, launched boat and went back to home dock. That was Tue., Sun. (Easter Sun.) the marina called me to say my boat was down two feet in it's slip. Had Tow Boat meet me at the boat and they had pumped it out but not before the water went over every thing up to the top of the settee cushions. Dock neighbor said he saw it pumping water on Friday and meant to call me but forgot. Bottom line, ins. company totaled the boat. The same part on an old Perko had broken and allowed the top to lift up. Pump stopped some time between Friday and Sun. IT'S A BOAT

[Simi 60]

Originally Posted by maine50

I can't stress enough how important a BILGE ALARM is. It's the fall back- save your boat solution. Once something happens and the water gets above the floor boards your chance of saving the boat diminishes.

And multiple bilge pumps with float switches at different heights.

And then there is maintenance, has to be done if you want to stay safe.

[derfy]

Originally Posted by captrod

I made the same item into a key ring. Had the boat on the hard for two weeks. Did a great bottom job. Cleaned strainers, put cover back on over rear of engine, launched boat and went back to home dock. That was Tue., Sun. (Easter Sun.) the marina called me to say my boat was down two feet in it's slip. Had Tow Boat meet me at the boat and they had pumped it out but not before the water went over every thing up to the top of the settee cushions. Dock neighbor said he saw it pumping water on Friday and meant to call me but forgot. Bottom line, ins. company totaled the boat. The same part on an old Perko had broken and allowed the top to lift up. Pump stopped some time between Friday and Sun. IT'S A BOAT

Wow...just what I feared could have happened to us.

[derfy]

Thanks .... great tips.