Rusty water tank on sitting on damp ply boards

[Rainyday]

Just bought a 1994 narrowboat, I'm a complete novice using my holiday to renovate and will hopefully move in end of Jan - really appreciate your advice! 

 

1. Lifting the vinyl flooring revealed damp and mold through the ply floors. Bed came up to reveal rusty water tank (see pic) . I wasn't intending to strip the boat down to ballast but clearly this floor is coming up and will be replaced before laying anything else down. 

I need to decide if I keep the poo tank or go with another toilet system (can't get my stomach around the idea of keeping a month's worth of poo under my head!)

Lifting the water tank though looks a difficult job and means replacing the bath/bedroom wall (which is dry). IF I decide to keep the tank and just treat the rust then for an easier life I could just cut the flooring around the tank leaving the piece that's under there. Maybe I could treat it to prevent the damp spreading to new adjacent wood? 

 

2. Middle to front of boat looks dry. Would you recommend lifting some of the mdf to double check? And should I put some hatches in throughout the boat for future ease before laying reclaimed floorboards? (could maybe hide under a rug/sofa. 

 

I'm on my own here except for nice friendly boaters nearby who I've asked a million questions but don't want to overdo their kindness! 

Thanks! 

 

[Cheshire cat]

You will get more detailed advice from othersbut my first concern would be to find out why the floor is damp. That is a large area and you need to find the source of the damp otherwise any new flooring will become damp in the near future. How much water is sitting under the floor at the back of the boat? It could have come in through the windows or leaking mushroom vents. It could have come in through the stern gland and might have come in through a hull fitting that is leaking.  I'm sure there are other possibilities. It looks to be more than just condensation.

 

That tank might have years left in it or might start leaking next month. Usually they rot from the inside out because the inside will be unpainted steel. 

[Alan de Enfield]

I think your 1st challenge is to find out why the floor is wet and mouldy - if it is the water tank that is leaking it needs to come out, if it is a leaky joint in the water pipes then it needs fixing, if it is water leaking around the windows then they need to come out and be re-sealed.

 

It is pointless continuing replacing 'stuff' without finding the cause as all your new stuff could be in the same condition in a few weeks.

 

Water leaks can be terrible things to resolve as the water can leak in (for example) at the front and run behind the lining and then 'appear' near the back.

 

Edit Cross posted with CC - at least we agree on the same course of action.

Edited December 28, 2018 by Alan de Enfield

[Tacet]

23 minutes ago, Narrow newbie said:

IF I decide to keep the tank and just treat the rust then for an easier life I could just cut the flooring around the tank leaving the piece that's under there. Maybe I could treat it to prevent the damp spreading to new adjacent wood? 

 

Thanks! 

 

 

It would be unusual to sit a steel toilet waste tank on a top of a timber floor - so have a prod around to make sure that is the situation.  If it is on a timber floor, it suggests the tank was installed late in the fit-out or retro-fitted, so it may come out without too much trouble.

 

But there a few guarantees when it comes to what a previous owner may have done.

[koukouvagia]

I wouldn't rule out condensation.  Before doing anything drastic and having eliminated the more obvious sources of damp - leaking pipes, windows etc. I'd cut a gap in the flooring all around the tank.  This would prevent anymore damp from the tank spreading to the floor and will give it time to dry out and you could see if the tank was leaking.  You could also then see if there was any water in the bilge. 

 

 

edited because I didn't read the title properly.

 

 

 

 

Edited December 28, 2018 by koukouvagia

[alan_fincher]

48 minutes ago, Tacet said:

It would be unusual to sit a steel toilet waste tank on a top of a timber floor - so have a prod around to make sure that is the situation.  If it is on a timber floor, it suggests the tank was installed late in the fit-out or retro-fitted, so it may come out without too much trouble.

 

But there a few guarantees when it comes to what a previous owner may have done.

I agree with Tacet.

I assume it is a foul water toilet tank, despite your description of "water tank".

Seating it on top of flooring sounds unusual, and it does sound to have been done by someone other than a professional.

 

Was this an "owner fit out" boat?

Clearly if it is a toilet waste tank the toilet must be some kind of macerator or vacuum type, and not a simple dump through.  It is not obvious from the picture how easily it can be detached from the associated pipework, but the bulkhead certainly seems to be in the way, unless you can disconnect the pipes elsewhere, and drag the whole thing away from the bulkhead a bit.

I can't go with a "condensation" diagnosis, personally, I feel sure something must be actively leaking.  I cant imagine though why it has so much rust on the top - not what I'd expect, really.

[Phil Ambrose]

To give us a bit more of a clue, it appears from the pic that part of the tank on the left hand side actually passes through the bulkhead and only one pipe is visible.

It may well be a sort of "L" shaped tank with who knows what in the other side of the bulkhead.

I agree that the amount of rust looks too much for condensation.

I would look at insulating the tank if you end up keeping it in situ but for me I would launch it and get a Thetford.

Phil

[Rainyday]

8 minutes ago, alan_fincher said:

I assume it is a foul water toilet tank, despite your description of "water tank".

Seating it on top of flooring sounds unusual, and it does sound to have been done by someone other than a professional.

 

Was this an "owner fit out" boat?

Thank you all for your replies. 

 

That's correct, it's a black water tank. It's sitting atop sheet lino, atop wood. Strange but glad it makes life easier to remove if that's what I decide. The boat was previously used by a long term rental company so its had quick fixes to keep it "liveable" but not the tlc coming from an owner occupier. The engine and the hull came out well in survey so I felt reassured that I could handle the soft components. 

 

I don't think the tank is leaking as no smell of waste. 

 

There was previously water in the back of the boat from a central heating leak. I think this has seeped all the way up. There was a lot of water in the bilge but since mopping up it is draining almost dry. Possibly that leak and years of condensation was capable of causing this mess. 

[alan_fincher]

2 minutes ago, Phil Ambrose said:

To give us a bit more of a clue, it appears from the pic that part of the tank on the left hand side actually passes through the bulkhead and only one pipe is visible.

It may well be a sort of "L" shaped tank with who knows what in the other side of the bulkhead.

You may well be right, now I look at it again.

Could OP please confirm if this is the whole tank, or part of an L shaped one?

If so a picture of what's the other side of that bulkhead wuld be very helpful!

[bizzard]

It was fairly common to lay the toilet tank on the floor in old usually hire boats. Harborough Marine did it with half the tank in the bog with dump through and passing through the bulkhead with the rest of it under the bunk bed, similar to the op's set up.

[Rainyday]

2 minutes ago, alan_fincher said:

Could OP please confirm if this is the whole tank, or part of an L shaped one?

If so a picture of what's the other side of that bulkhead wuld be very helpful!

Yes it's an L shaped one. The toilet sits on top of the tank. Not a macerator, just goes straight down ?

The other picture is inside the cabinet below the basin, showing the pump out pipe connection. 

[bizzard]

7 minutes ago, bizzard said:

It was fairly common to lay the toilet tank on the floor in old usually hire boats. Harborough Marine did it with half the tank in the bog with dump through and passing through the bulkhead with the rest of it under the bunk bed, similar to the op's set up.

Much better to have the tank sitting on the wooden floor than on cold damp steel cross members or the bilge plate.

[Stilllearning]

Hi

contrary to others here, I suspect it might be condensation, it is astonishing how much water vapour can be trapped inside a steel hull. You mention the previous use of the boat, which might suggest that it was not heated by solid fuel, which is the way to drive off damp and keep woodwork dry. MDF etc are just sponges. If you have a stove on board, use it as much as possible, and air the cabin whenever you can.

The loo tank should come out, as my preference would be for a cassette type loo, so much less to go wrong with it - no piping, though it will need emptying much more often. Buy at least one spare cassette.

Yes, cut access hatches in the floor, to the rear of the cabin, for ventilation and so you can see if any water accumulates. 

Leaks, if any, are most likely at window frames or roof vents, though pip work joints are possibilities too.

[Phil Ambrose]

So it seems that the consensus is rip it out and go for a Thetford, should be a relatively easy job (provided you empty the tank first of course)

Phil

[WotEver]

Just now, Phil Ambrose said:

So it seems that the consensus is rip it out and go for a Thetford, should be a relatively easy job (provided you empty the tank first of course)

Phil

That’s what I’d do but as I said in my first post in this thread it’s all down to OP’s preference at the end of the day. 

[Rainyday]

Thanks! Good to get the advice of experienced boaters! If the consensus is that cassettes aren't too inconvenient, I'm leaning towards that also. Could do with the floor space in what's going to be my walk in wardrobe/garage too

[Stilllearning]

It seems to be the OP’s preferred loo solution as well, ref post #1

[Alan de Enfield]

2 minutes ago, WotEver said:

That’s what I’d do but as I said in my first post in this thread it’s all down to OP’s preference at the end of the day. 

Agreed - no sensible person has 'months worth of deposits' kept on board - this is the 21st century after all.

 

Bucket & Chuckit

[Boater Sam]

Give the tank a good hammering to get the rust off, if it stands that it is likely to be OK. Most rust through on the top first around where the dump through bowl is mounted.

I prefer pump out loos, saves carrying buckets of sh*t around every other day.

MDF is spawn of the Devil on canal boats, its a sponge and useless once wet.

Its the last material to use for flooring. OSB is best, better than most modern plywood.

[Dr Bob]

3 hours ago, Boater Sam said:

 

I prefer pump out loos, saves carrying buckets of sh*t around every other day.

 

Sam of course is right and there are two sides to the Loo problem.

I would never have a dump through though and ripping this one out to replace it with an HDPE tank would be difficult.....so replacing with a cassette is the obvious place to be. However, then you are carrying buckets of sh*t around every 3 days and constantly looking for places to empty them. I much prefer taking my boat to a little man, for him to pump it out, each month.

[Stilllearning]

2 minutes ago, Dr Bob said:

Sam of course is right and there are two sides to the Loo problem.

I would never have a dump through though and ripping this one out to replace it with an HDPE tank would be difficult.....so replacing with a cassette is the obvious place to be. However, then you are carrying buckets of sh*t around every 3 days and constantly looking for places to empty them. I much prefer taking my boat to a little man, for him to pump it out, each month.

But keep a cassette loo in a cupboard somewhere for when it’s desperately needed.

[alan_fincher]

Just be aware that if you are hoping to get space back by getting rid of a pump out tank you do need to allocate at least a small part of that saved space (or some other space) to store at least one spare cassette.  If you actually go boating, then I'd say 2 spare cassettes is a stronger option. (Obviously to some extent the number you need is dictated by how fast you fill them).

We favour cassette, but it is not a "one solution fits everybody" thing, and other options may work better for other people.

[ditchcrawler]

Composting

[Cheshire cat]

Everyone seems to be assuming the pumpout tank is the source of the damp but the OP has said there is no smell. Believe me when it starts to leak there is a smell, a very strong one. You have given up on finding the leak in favour of a pumpout versus cassette discussion.

[WotEver]

4 minutes ago, ditchcrawler said:

Composting

Even more space needing to be put aside for all the tubs of festering poo to compost down