How rare is a hole in the hull?

[Doodlebug]

Hi all, long time no see!

 

All systems working well on the boat, and much to report back on. I'll write up some review/articles soon.

 

Quick question though to put my mind at rest. A couple of weeks ago I randomly switched on the bilge pump and it sucked out a fair bit of water. I can't measure it since it goes straight outside but about 30 seconds of pumped water.

 

This week I did the same thing and possibly the same amount, maybe more came out.

 

Today I did the same, and put a few weights on the side of the boat to make sure it was tilting the right way and I paid attention to how much water was going out. There was at least a minute or two of pumping water from under the boat.

 

Now I have a few suspicions. One is that ever since we bought the boat the water pump has turned on every couple of hours just to recharge the pressure - which never seemed to be a problem. I assumed the pump is allowing the pressure to go back into the main tank. But maybe this isn't the case. Although to be honest its always done it so quite why more water might be leaking I don't know.

 

Another possibility is the shower somehow leaking into the bilge. Im going to do some tests on this.

 

One other change is the eberspacher has been fitted. At the moment it is sucking the air from an area under the deck which is not insulated. i.e. just metal. Could it be that (now there is far more airflow into this area) condensation is running under to the bilge? The floor in the area is always damp/wet but a minutes worth of water a week seems like alot of condensation.

 

Anyway - back to my main worry. Is it possible for a boat to just start leaking through the hull? We haven't crashed recently so no sudden stresses on the hull. But the boat is in need of blacking. Its never been blacked whilst we have had it. Supposedly it was blacked a year before we bought it and we have now had the boat 3 years. But thats me trusting the seller.

 

Could the boat rust through and start leaking? More to the point is it possible for the boat to rust more in one area than another? I can access about a square meter of the floor of the boat and there is no sign of excessive rusting. And all seems sound. The same can be said for the sides of the boat, when I reach into the water the paint and metal seems sound. But could there be an area somewhere where it has rusted through?

 

Obviously I need to do some proper research into whether its a leaking pipe etc but the boat rusting through is the most worrying and expensive reason i can think of.

 

Hope that all makes sense. I'm hoping someones going to say that Narrowboats rusting through is unheard of unless there are very visible signs of neglect.

 

Btw the boat is 23 years old.

 

Thanks.

 

Doodlebug

[Wanted]

My money is on the water pump leaking. That intermittent noise it makes may well indicate that water is escaping and ending up in the bilge.

 

First port of call would be to check all around the pump. If it's wet underneath then that's yer answer. Failing that you will need to check and joints in the water pipes. From taps, t junctions to boiler etc.

 

Also, what stern do you have? My cruiser stern is a bugger for letting in water.

[Doodlebug]

My money is on the water pump leaking. That intermittent noise it makes may well indicate that water is escaping and ending up in the bilge.

 

First port of call would be to check all around the pump. If it's wet underneath then that's yer answer. Failing that you will need to check and joints in the water pipes. From taps, t junctions to boiler etc.

 

Also, what stern do you have? My cruiser stern is a bugger for letting in water.

 

I would agree with you but its done it for years so why have I only just found the problem. I'd have had it coming through the floor if i'd not checked for 6 months. Last time I pumped out was last winter.

 

Not sure how you'd descriptive our stern. Its an unusual build but impossible to leak through since the deck is totally flat and the doorway is the only 'hole' into the boat and thats 2 inches above the deck. Checked the Cratch and theres no water collecting there.

 

The only real change is the eberspacher and it getting cold. A dehumidifier can make a few litres a day. So maybe its possible.

 

Someone tell me we can't sink!

 

Cheers!

[Wanted]

If you are pumping water out quicker than its coming in then you'll be alright.

 

I had a slow leak from a pump on my old boat at I didnt know about it until I shifted a load of coal on the roof, it all ran down to the back where the bedroom was and I was ankle deep when I got out of bed. It had been sat in the cabin bilge for a while.

 

I am not suggesting that it dosent happen, but I haven't personally heard of a Steel NB sinking because of a hole. It's always been either via the stern gland or when a outlet has gotten too low.

 

By stern I mean is it a trad, semi or cruiser stern.

[kevinl]

Back to the OP's topic (as required ) how many boats actually sink from a hole in the hull? Water in the bilge is bad but "How rare is a hole in the hull?" I'd say very rare, it's much more likely to be an internal leak.

K

[Scholar Gypsy]

It does sound like a water system team.

 

It is also worth checking the weed hatch - if you have been moving the boat recently. The one and only time I thought I had a hull leak (1980), that was the problem. Somebody had not tightened it enough....

[Lady Muck]

Did you get a survey when you bought the boat? Only that we have have had boats of similar age to yours on our moorings up here and they have had holes in the hull. But at the same time not been blacked or had any anodes left either.

If I were you I'd be booking a dry dock sooner rather than later, I'd be wanting to see what is going on with my hull if it hadn't been blacked for four years possibly more.

[bargemast]

I think that you're in for a quick trip to a drydock, just for your own peace of mind to make sure that there's no hole in your hull.

That will give you a better chance of being able to sleep without all sorts of worrying ideas going through your head.

 

Good luck,

 

Peter.

[bizzard]

Get a cheap microscope. Take a sample of the canal water from outside and from in your boat, examine and compare the two differences and for signs of marine life. Is your stern gland leaking badly?

[Bloomsberry]

I discovered some water in the cabin bilge that I've never seen before. After a good investigation have found my side hatch has developed a leak. I assume during summer it just evapourates but in winter when it's colder it doesn't and tends to accumulate.

 

Earlier on in the year my overplated boat was taken out of the water and a jet of water appeared out of badly pitted section of the plate. Got the offending area patched over and as a precaution had the plating welds redone ( at some cost I must add ).

 

The moral of the story - If you've an overplated boat then when next in dry dock inspect the hull intesively after it's come out of the water and any penetrations will be revailed by patches of moisture ( or a water jet in my case !).

[Mike Tee]

Where in the boat is the bilge pump?

Often, they are at the stern and only drain the area immediately under the stern gland - if yours is like this then you've probably found the leak.

Also, you need to collect some of the water being pumped out - is it soapy? Oily? Rusty?

[John V]

That sounds too much water for condensation, is your engine bilge common or is it separate? if separate that will eliminate the stern tube (one of the most common sources of leaks) Corrosion holes in the hull are definitely not uncommon in a hull of your age if the maintenance has been a bit suspect. Saying the hull is fine where you have checked, tells you nothing about the bits you can't check. Corrosion can be very localised.

As others have said firstly eliminate all possible internal sources of water, I don't like the sound of the freshwater pump cycling on its own.....that is often a symptom of a leak in the pipework. If you can, try leaving the pump switched off for a day and see if there is any change in the amount of water being pumped out good luck John

[Athy]

Stern gland leakage sounds the most likely culprit. Is there grease in your greaser?

I recently saw a boat on which welding had to be performed because you could see daylight through holes around the exhaust pipe. As that orifice was only a couple of inches above normal water level, it would surely have let in enough water to sink the boat if it had been left unattended.

[Neil2]

You don't say how long the water pump fires up for but every couple of hours is not normal. If your system is leak free the pump shouldn't trigger at all.

 

That's almost certainly the cause of your problem. But regarding the question posed, I suspect there are scores of narrowboats floating around the network with perforated hulls, but the blacking etc on the outside prevents them from sinking. I know of one tale where a boat was booked in for grit blasting and when they extracted it from the water there was practically nothing left of the hull, it really was just the blacking that was holding it together. Not sure what happened to it either as it was in such a state that it couldn't even be overplated.

 

Ok you can take the boat out of the water and scrape around at the hull but the only way you will know for certain what it is truly like is by having it grit blasted.

[ditchcrawler]

My water pump pumps over half a litre of water every time it runs, so if yours is the sam and cuts in every 2 hours that could be 12 lt of water a day going into the bilge

[sherbert]

returned to my boat after being away from it for a week and found that the water tank was empty and I was sure i had filled it previously so I filled it and on leaving the boat I could hear water running into the canal from what I thought was the washbasin outlet On inspection I found it was coming from the outletfrom the pipe connected to the PRV Had the PRV not had an outlet pipe all the water would have gone to the bildgeIs this the cause of your leak Worth acheck

[b0atman]

The prv on calorifier has a facility that you turn it to check that it is clear of scale but if some scale gets stuck under valve seat then water will constantly flow .

I found my water leak on connection to sink cold tap the hep 20 pipe had been fitted without a metal ferrule insert allowing connection to work loose.

[Alf Roberts]

 

 

Could the boat rust through and start leaking? More to the point is it possible for the boat to rust more in one area than another? I can access about a square meter of the floor of the boat and there is no sign of excessive rusting. And all seems sound. The same can be said for the sides of the boat, when I reach into the water the paint and metal seems sound. But could there be an area somewhere where it has rusted through?

 

 

Have a look in the water in the area of the bilge pump. If it has mud in it, it's a hull leak, if not it's your fresh water system (or the stern gland but that' easily eliminated)

[Doodlebug]

Thanks for all the pointers.

 

Its deffo not the stern gland. Mainly because we don't have one (its powered by an outboard) and therefore not the weed hatch either!

 

Im going to have a go at some of the ideas suggested. Although not sure how I can check the quality of the water, the bottom of the boat is full of rusty water. It always has been. This was about a year ago when I had the floor up - and there was no sign of bad rust. It was just like when you empty the central heating. Just brown water.

 

Going to clear out under the bed so I can get down to the water pump, it might be a leak beforehand which would mean the pump doesn't buzz. The water pump goes on maybe once every4 hours but it could just be that the pump didn't turn on when I used the sink and a vibration in the boat has set of the pressure switch? Once its come on it doesn't seem to come on again, or at least until the sink is used.

 

So is it really possible to have no signs of rusting within the boat, no signs of rust on the outside sides of the boat and to still have an area which is not visible corrode through?

 

Also the anodes are still intact and not even half used.

 

One problem is we are going to be stretched in the summer, which will include blacking. It could be a big waste of money to go and get blasted and blacked now when we will be having it redone in about 6 months.

 

The inside of the water tank is perfectly rust free too.

 

Really hoping its not rust - overplating sounds expensive.

 

Thanks again for the pointers.

[trackman]

Go through the easy checks systematically first. If they are all negative then it may point to a leak in your hull.

However, when we've had a leaky water pump it has easily created the sort of volumes of water in the bilge that you describe. What's more, the pump wasn't obviously wet on the first occasion. The water must have emerged in a fine spray from the leaky joint in its body and then hit the adjacent steelwork, running down from there into the bilge.

There were a lot of damp surfaces but the pump itself and the board it sat on were dry! It was only when I wrapped a cloth round it that it was obvious that the pump was the source. Had me worried about leaks in our hull for a day or two!

[captain birdseye]

one problem is we are going to be stretched in the summer, which will include blacking. It could be a big waste of money to go and get blasted and blacked now when we will be having it redone in about 6 months.

 

.

If you suspect the hull get it sorted now. Why would blacking it now be a problem. If it is done now it won't need redoing in six months

[Traveller]

If you are having the boat "stretched" you need to be certain the hull is sound.

[David Mack]

 

Anyway - back to my main worry. Is it possible for a boat to just start leaking through the hull? We haven't crashed recently so no sudden stresses on the hull. But the boat is in need of blacking. Its never been blacked whilst we have had it. Supposedly it was blacked a year before we bought it and we have now had the boat 3 years. But thats me trusting the seller.

 

Could the boat rust through and start leaking? More to the point is it possible for the boat to rust more in one area than another? I can access about a square meter of the floor of the boat and there is no sign of excessive rusting. And all seems sound. The same can be said for the sides of the boat, when I reach into the water the paint and metal seems sound. But could there be an area somewhere where it has rusted through?

 

Have you read this thread and the blog which it refers to?

[Kwacker]

Our boat was 6 years old when we bought her, and looking through the extensive repair & maintenance paperwork that accompanied her, and a hull survey from 6 months previously, there was no cause for concern.

After about 5 months of regular use for our new toy, she sprang the sort of leak that could sink a boat in a week.

The source was a poor weld on the stern tube, that had had a blow hole in it from the day she was built. This had managed not to leak for 6 years, being bunged up with slag and blacking.

Luckily I spotted it at the end of the trip when the "bung" must have come out. It was a Sunday night, so all I could do was hope the bilge pump was up to the job (it wasn't - I'll not use one with a float again*).

I got to the marina at 5.30 the next morning to find 5" of water in the engine bilge which I pumped out while I waited for the marina guys to get on the job at 8.30.

Only after it had been re-welded and put back in the water did I realise that there was a small bleed hole through to the cabin bilge, about 3" up from the baseplate which had allowed water through, but not back out. Luckily, we found that there was an access under the back steps and pumped out a few more gallons over the next two or three days.

That was 4 years ago, and the paranoia it induced has now passed but we still take a quick peep in the cabin bilge most times we use the boat.

 

I still shiver a bit when I think of it, because, after only 4 months of boat ownership, if we had left her on the towpath in the middle of nowhere for a week or so, as we often did, we would have come back to find her on the bottom.

 

* despite regular cleaning, a bit of grease had blocked the breather in the float housing - the pump just sat there under water doing nothing. I removed a tiny blob of grease from the hole, and off it went - I replaced it with a Whale automatic pump that isn't bothered by the odd bit of grease.

Edited December 19, 2014 by Kwacker

[pophops]

The water pump cutting in every so often is the clue. If the pump needs to re-pressurise occasionally then, provided you don't have a dripping tap or shower mixer, you have a leak. Either a leak of pressure back into the tank (unlikely), or a water leak into the boat. Given a conventional bilge arrangement, a build up of water in the cabin bilge denotes a leak from the water pump or domestic water system. If the cabin bilge is dry then the odds are that the water is escaping from the PRV on the calorifier and draining via an overflow into the rear bilge.