Oh the irony

[Kelpie]

After our last overnight passage I found a fair quantity of saltwater in the bilge under the engine. We'd done the bulk of the miles under motor so I guessed it must be an exhaust leak, and spent most of yesterday crawling all over the engine and following the exhaust to find the hole. Nothing found.

The culprit turned out to be the outlet hose for one of the bilge pumps. For some reason this outlet is right at the water line, and a previous owner had fitted too large a hose to the valve tail and crushed it down to fit. Somehow it had held up for many years but a long rolling passage was too much for it and we shipped maybe 20l of water.

Having replaced the hose with the correct size, I'm wondering whether to keep this outlet closed most of the time as that might actually be the safest option! But it's buried at the back of a cockpit locker so if I ever did need to use it we would lose a few minutes opening it.

Anyway I thought it was worth posting... just in case it helps anybody else to avoid being sunk by their own bilge pump...

 

[PetiteFleur]

I had a similar situation - found I shipped water via the bilge pump when motoring hard, the stern drops and water flows down the pipe to the bilge pump. Sorted by fitting a non return valve and a 'U' in the pipe.

 

[PhillM]

Would be tempted to put a U in the pipe rather than a valve or seacock. You never know when you need it and those are the moments when its easy to forget important stuff like opening the valve. Also a non-return can get stuck open or closed. If you can get a loop above the waterline at all states of heel, that would sort out the issue and not leave anything for you to have to remember in a emergency.

 

[Kelpie]

Would be tempted to put a U in the pipe rather than a valve or seacock. You never know when you need it and those are the moments when its easy to forget important stuff like opening the valve. Also a non-return can get stuck open or closed. If you can get a loop above the waterline at all states of heel, that would sort out the issue and not leave anything for you to have to remember in a emergency.

The pump itself is well above the waterline. It's just that the skin fitting is low enough that a failure in the hose at that point led to water getting in. A NRV or swan neck wouldn't have helped.

 

[Sandy]

Why people place skin fittings for bilge pumps so low is beyond me. Mine is 50 mm below deck level.

 

[Kelpie]

Why people place skin fittings for bilge pumps so low is beyond me. Mine is 50 mm below deck level.

I agree. I understand it for cockpit drains.
I think next time we haul out I might move it.

 

[dansaskip]

This gets me thinking of the wisdom or otherwise of designers/builders or whoever would fit a non valved skin fitting close to the waterline. To my mind it's building in trouble. On my boat my bilge pump outlet is way up near the gunwales.

Ah Sandy beat me too it

 

[Kwik Decision]

Why people place skin fittings for bilge pumps so low is beyond me. Mine is 50 mm below deck level.

One reason is that if you use the pump often (traditional packed stern gland, so you'll get some water in the bilge?) you'll get a dirty mark down the hull from the skin fitting. Personally I'd rather have the skin fitting high up, and clean more often though...

 

[Stemar]

One reason is that if you use the pump often (traditional packed stern gland, so you'll get some water in the bilge?) you'll get a dirty mark down the hull from the skin fitting. Personally I'd rather have the skin fitting high up, and clean more often though...

I got round that problem by putting a bit of plastic pipe in the through hull so it stuck out about a centimeter. Fix it with an easy to remove sealant, because it will get broken off eventually.

 

[Sandy]

One reason is that if you use the pump often (traditional packed stern gland, so you'll get some water in the bilge?) you'll get a dirty mark down the hull from the skin fitting. Personally I'd rather have the skin fitting high up, and clean more often though...

Currently the boat has a packed stern gland, I hope to change that this winter and reduce the amount of cleaning I need to do

 

[coopec]

Putting the bilge water outlets so close to the waterline is a bit of a worry? If it was mine I think I'd make sure the through hull fitting was Trudesign (As I understand it noncorroding)

 

[geem]

Why people place skin fittings for bilge pumps so low is beyond me. Mine is 50 mm below deck level.

Where is you engine exhaust? Where are your cockpit drains, toilet outlet? Sink outlet? Wash hand basin outlet? Yes, with a bilge pump you have the option to discharge high up the top sides and it makes sense but proper fittings with the correct pipe and double clipped it's no more of a risk than any other below the water pipe fitting.

 

[Supertramp]

I have had the same problem. I have 5 outlets in a row about 20cm up from the waterline. Two are engine/generator cooling and stainless steel. Two are bilge pumps and one is deck drains. They are simple Whale plastic through hull fittings. One had cracked from jubilee clip pressure and another "lost" its outer face where lifting slings sometimes crush it and UV degraded the plastic. Some water seepage was the result. I have a stern gland and a deep bilge so some water entering is routine and confirms the bilge pumps work (!).

I have replaced some of the plastics with brass which allows a solid double clamping of the pipe which fixed the leaks. They are above water outlets so I don't have a valve and if they ever broke off I can access and plug them. Brass is OK I think as they are not immersed. I would not want seacocks on deck drains, bilge pumps or cooling water outlets. I always assumed that the above waterline outlets were positioned so that seacocks were not needed.

 

[geem]

I have had the same problem. I have 5 outlets in a row about 20cm up from the waterline. Two are engine/generator cooling and stainless steel. Two are bilge pumps and one is deck drains. They are simple Whale plastic through hull fittings. One had cracked from jubilee clip pressure and another "lost" its outer face where lifting slings sometimes crush it and UV degraded the plastic. Some water seepage was the result. I have a stern gland and a deep bilge so some water entering is routine and confirms the bilge pumps work (!).

I have replaced some of the plastics with brass which allows a solid double clamping of the pipe which fixed the leaks. They are above water outlets so I don't have a valve and if they ever broke off I can access and plug them. Brass is OK I think as they are not immersed. I would not want seacocks on deck drains, bilge pumps or cooling water outlets. I always assumed that the above waterline outlets were positioned so that seacocks were not needed.

Our topsides are pretty high. The shower pump outlet is high up on the topsides. We had a small boat alongside us in a harbour once. The shower outlet filled his cockpit with nice frothy water ?
Maybe that's why they are often lower down the hull. Our main bilge pump outlets are bronze and 6 inches above the water. The pipes loop up in the engine room to deck level.

 

[coopec]

Our topsides are pretty high. The shower pump outlet is high up on the topsides. We had a small boat alongside us in a harbour once. The shower outlet filled his cockpit with nice frothy water ?
Maybe that's why they are often lower down the hull. Our main bilge pump outlets are bronze and 6 inches above the water. The pipes loop up in the engine room to deck level.

Jonathon

A bit off topic but what type of shower pump do you have - diaphragm, centrifugal, Jabsco...?

 

[PhillM]

Our topsides are pretty high. The shower pump outlet is high up on the topsides. We had a small boat alongside us in a harbour once. The shower outlet filled his cockpit with nice frothy water ?
Maybe that's why they are often lower down the hull. Our main bilge pump outlets are bronze and 6 inches above the water. The pipes loop up in the engine room to deck level.

Bonus, he got all your warm water without the need to boil his kettle

 

[Stemar]

Bonus, he got all your warm water without the need to boil his kettle

Downside, he took a bath in his cockpit