Damp issues

[Ex- Member]

I'm surprised why people have this problem. I'm sure it simply down to poor ventilation.

 

This thread had me wondering so we've just opened up the hatch below the cratch doors to the water tank and inspected the area. There isn't a single drop or even misting of condensation anywhere. The S/S tank isn't insulated, neither are the hull sides. The Red primer is the original. I've never seen any condensation in this area. Just took these photo's heating is on boat temp 20c

 

 

 

 

The flat cardboard box has been there years. I use it to crawl on to access stuff stored around the tank.

 

 

I've been meaning to paint in here for years. I'm sure it has condensated at some time or the other, but if it did fresh air would clear it quickly.

 

The air vents either side of the cratch doors that trunk to this area are clearly doing the business. Better known as low level ventilation I believe.

[Bones]

Interesting. I put my condensation down to having a large front well deck. However, have you got insualtion between the space you photograph and the cabin?

 

My boat rarely gets up to 20deg.

[Ex- Member]

Interesting. I put my condensation down to having a large front well deck. However, have you got insualtion between the space you photograph and the cabin?

 

My boat rarely gets up to 20deg.

 

Either side of the opening hatch is. I've just realised I haven't done the back of the hatch door. I have cut out the insulation to do it though It's somewhere on the boat, I ordered some extra strong double sided tape to do it about 3 years ago

 

IT WILL be done this summer. It's one of those damned jobs, out of sight out of mind. have time to sort now though.

 

Bear in mind also the Bubble Stove is on the right bulkhead to this area also, but as mentioned insulated. The central heating return pipe is also insulated.

Edited January 22, 2014 by Julynian

[blackrose]

 

 

Again as you well know we have ample fixed ventilation with them blocked. It's incredible how many times you need reminding of this.

 

 

It's perfectly credible that I didn't know that your low-level ventilation by itself was sufficient to safetly take care of all oxygen burning appliances and people onboard. I did ask you once about this but you didn't answer - or you may have answered later but I'd already left the thread and didn't return, so i didn't see your answer. You have to understand that we don't all use this forum in the same way - sometimes I don't bother or just forget to go back to threads. I can't keep track of every thread I've contributed to.

 

Anyway, I'd be interested to know how many low-level vents and of what size you have on your boat? You must either have lots of and/or large vents or you don't have many kW of oxygen burning appliances on your boat. If your low-level vents really do cover the needs of all your appliances, one wonders why you bothered to install all that extra ventilation in the first place?

 

The other thing is that the BSS recommends that the fixed ventilation is split evenly between high and low-level. The reason for this is so that as some warm air is lost through the high-level vents, this draws air in through the low level vents and thus forces fresh air to constantly circulate through the boat. With only low-level ventilation, depending on the conditions outside, you may not necessarily get this circulation.

 

 

 

When I first got heating on my boat I had quite a lot of condensation on the BT tube which is located just aft of the insulated bulkhead of the integral water tank. The tube was uninsulated. I got some cans of sprayfoam and covered the tube and since then it's been fine.

Edited January 22, 2014 by blackrose

[Ex- Member]

 

It's perfectly credible that I didn't know that your low-level ventilation by itself was sufficient to cover all oxygen burning appliances and people onboard. I did ask you once about this but you didn't answer - or you may have answered later but I'd already left the thread and didn't return, so i didn't see your answer. You have to understand that we don't all use this forum in the same way - sometimes I don't bother or just forget to go back to threads. I can't keep track of every thread I've contributed to.

 

Anyway, I'd be interested to know how many low-level vents and of what size you have on your boat?

 

When I first got heating on my boat I had quite a lot of condensation on the BT tube which is located just aft of the insulated bulkhead of the integral water tank. The tube was uninsulated. I got some cans of sprayfoam and covered the tube and since then it's been fine.

 

Hi br

 

The 2 vents are basically 10 inch x 4 inch fixed louvre Brass vents similar to this. but with 6 louvre slats aside on each not 4.

http://www.ebay.co.uk/itm/9-x-3-Louvre-Vent-Heavy-Gauge-Gold-Brass-Anodised-Aluminium-Grille-Cover-/251190095557?pt=LH_DefaultDomain_3&hash=item3a7c18aec5

 

They're each side of the double opening cratch doors. There's a cavity in the main bulkhead ours being 60mm, you need keep a section of this cavity to assist the through air flow, (no insulation in the way) I simply added 2 x 60mm strips of timber to create a conduit. This drops down into the bow bilge area where the water tank is located. The vents also supply fresh air flow to the bilges. Our bilges are bone dry. We also have holes in the floor where fans are located for drawing cool air in the summer.

 

Low level venting can be achieved by letting in cold air through louvre vents in doors, bulkheads or by ducting from a higher level. Cabin bilges should also be open to unrestricted ventilation to prevent the formation of mould from excessive moisture and to protect against the build up of gas in the unfortunate event of system leak.

 

The examiner will carefully examine any fixed ventilation for fly screens or louvres & carefully measure these potential restrictions so as not to render calculations inaccurate.

 

http://www.thefitoutpontoon.co.uk/buying-building-canal-narrowboat-ventilation.html

[David Mack]

If the OP is a liveaboard then he will be constantly producing water vapour inside the boat from breathing, cooking, clothes drying etc. If the shell is properly insulated (and if the fitout is a bit slapdash that may or may not be the case) and the windows are double glazed there will be few places for condensation to occur. So the uninsulated panel between the living space and the unheated/unninsulated water tank area will generate lots of condensation. The answer is twofold - ventilation and insulation. That bulkhead must be insulated, and it looks to me as if you may need to add more ventilation or just have the windows (more) open, particularly when cooking etc.

 

I would be less worried about the condensation around the water tank. It was probably fine until you removed part of the bulkhead. Now you have exposed a new cold area to the warm humid air from the living space it is bound to result in more condensation. If it is sealed off from the living space by an insulated bulkhead, and preferably given a little ventilation of its own it should be fine.

[smileypete]

If you're living aboard and on shoreline and not heating by stove, something that would probably help considerably to keep humidity levels under control is an electric dessicant dehumidifier like the Meaco DD8L.

 

The other options are to leave windows open which will let a lot of expensively heated air out along with the humidity caused by living aboard, or heat with a stove which will draw the humidity up the flue.

 

Not entirely clear on what's going on with the damp whether it's rainwater getting in or condensation accumulating. Ideally all wood should be 'back primed' on hidden faces and ends to help stop it soaking up any water that may come into contact from behind, but most builders cut corners here.

 

cheers, Pete.

~smpt~

[blackrose]

 

Hi br

 

The 2 vents are basically 10 inch x 4 inch fixed louvre Brass vents similar to this. but with 6 louvre slats aside on each not 4.

http://www.ebay.co.uk/itm/9-x-3-Louvre-Vent-Heavy-Gauge-Gold-Brass-Anodised-Aluminium-Grille-Cover-/251190095557?pt=LH_DefaultDomain_3&hash=item3a7c18aec5

 

 

If that's the only ventilation you've got (presumably 2 vents at each end of the boat), then I don't see how this could possibly be adequate for a widebeam liveaboard with all the oxygen burning appliances like your stove, oven, hob, etc.

 

Did you do the calculation according to the BSS guide?

 

BSS Essential Guide 2nd Edition

Aug 2005

Ch8

Ventilation

The responsibility for the safety of anybody onboard your boat lies

with the owner or skipper. We advise strongly that boats have

enough fixed ventilation to feed all the appliances on board that

use LPG, coal, wood, oil or other carbon-based fuels.

Inadequate ventilation will starve the burners of vital oxygen resulting in

poor burning and that can produce highly toxic carbon monoxide.

Room-sealed appliances have their own external air supply built into

the flue ductwork, but other appliances take their combustion air

supply directly from the cabin space.

The ventilation requirement can be calculated by using the formula from

Annex B of PD 5482-3. It takes account of the number and type of

appliances as well as the people on board.

Minimum effective area (mm2) = [2200xU]+[650xP]+[440xF]

U = total input rating (kW) for all appliances (including cookers) without flues

P = number of people for which the compartment is designed

F = input rating (kW) for all open or closed flue appliances

The input rating for your appliances can normally be found on the

manufacturer’s plate on the appliance and/or in the operating instructions.

The ventilation requirement needs to be split as equally as practicable between:- high level (ideally cabin roof) & low level.

Edited January 22, 2014 by blackrose

[Ex- Member]

Well the BSS guy doesn't have a problem with it.

 

I would suggest the fact your bow thruster tube condensated would suggest you boat is actually the one suffering from lack of ventilation.

 

The calculations were done and the size of the front vents reflect that requirement.

 

There's also low level ventilation at the bottom of the cratch doors directly in to the cabin as well which is additional to the calculated requirement. As previously stated several times ventilation through doors and hatches can be regarded as fixed ventilation, so the lower section of both front and rear cabin doors again add and exceed further the calculation.

[blackrose]

Well the BSS guy doesn't have a problem with it.

 

I would suggest the fact your bow thruster tube condensated would suggest you boat is actually the one suffering from lack of ventilation.

 

The calculations were done and the size of the front vents reflect that requirement.

 

There's also low level ventilation at the bottom of the cratch doors directly in to the cabin as well which is additional to the calculated requirement. As previously stated several times ventilation through doors and hatches can be regarded as fixed ventilation, so the lower section of both front and rear cabin doors again add and exceed further the calculation.

 

Of course the BSS guy doesn't have a problem with it. Ventilation is NOT compulsory under the BSS! (How many times do we have to keep repeating that mantra?)

 

My bow thruster tube attracted condensation because it was just an uninsulated steel tube full of cold water. Nothing to do with ventilation. As soon as it was insulated it stopped attracting condensation. Therefore it was not a ventilation problem.

 

I still don't see how it's possible that the ventilation requirements of a liveaboard widebeam can be achieved with the ventilation you've described according to the BSS formula? You must be related to David Blaine or something, but it's your boat so you carry on...

Edited January 22, 2014 by blackrose

[nicknorman]

Well the BSS guy doesn't have a problem with it.

 

I would suggest the fact your bow thruster tube condensated would suggest you boat is actually the one suffering from lack of ventilation.

 

Of course the BSS guy doesn't have a problem with it. Ventilation is NOT compulsory under the BSS! (How many times do we have to keep repeating ... You must be related to David Blaine or something, but it's your boat so you carry on...

Would you two get a room, where you can whip each other with wet nettles in private. You know you want to.

On second thoughts, make that dry nettles - think of the moisture / condensation!

[Ex- Member]

 

Of course the BSS guy doesn't have a problem with it. Ventilation is NOT compulsory under the BSS! (How many times do we have to keep repeating that mantra?)

 

My bow thruster tube attracted condensation because it was just an uninsulated steel tube full of cold water. Nothing to do with ventilation. As soon as it was insulated it stopped attracting condensation. Therefore it was not a ventilation problem.

 

I still don't see how it's possible that the ventilation requirements of a liveaboard widebeam can be achieved with the ventilation you've described according to the BSS formula? You must be related to David Blaine or something, but it's your boat so you carry on...

 

However the low and high levels are checked.

Rob@BSSOffice

As various people hereabouts have already said, providing the adequate amount of ventilation is not done for BSS certification - it doesn't affect the issue of a certificate - it is done to keep the family and crew safe from CO poisoning.

The calculation is on fixed ventilation, but there is an allowance in the calculation and sign-off report for sea going vessels.

If the BSS examination report notes that there is an under provision, it may be material to the vessel's insurance and the boat owner's duties under the law of occupier's liability.

 

 

 

As I already stated.

 

He checked these vents as he did the mushroom vents. I'm sure if he thought there was a problem he would have at least given an advisory if there was an under provision.

 

We don't suffer condensation in any of these places. We don't suffer damp, we have bone dry bilges, that's because there's adequate ventilation throughout the boat, ventilating the bilges is an important factor in this. You're so called qualifications you've previously spouted then removed when questioned are clearly suspect. Spray foaming would stop condensation on a cold surface, that doesn't mean there's adequate ventilation.

Edited January 22, 2014 by Julynian

[Alan Saunders]

"Sorry, Staarek, this is what happens on the CWDF forum; two old hands, who think they own the forum forget to help a boater in distress and start their own battle.

 

It is just a lovers' tiff, please ignore it!

July and Black - BEHAVE yourselves!

 

Alan

[Staarek]

"Sorry, Staarek, this is what happens on the CWDF forum; two old hands, who think they own the forum forget to help a boater in distress and start their own battle.

 

It is just a lovers' tiff, please ignore it!

July and Black - BEHAVE yourselves!

 

Alan

 

I’ve been actually enjoying O/T! In the end we are all boaters and I find this info quite interesting. In fact I always thought that ventilation was compulsory under BSS, especially if you’ve got gas appliances on board, I believe that’s the case under RCD at least.

 

Coming back to the damp issue, I’ve got someone coming around tomorrow to have a look so I’ll keep you informed.

 

 

Agree with Nick, If they ignore you go direct to trading standards, it's totally unacceptable.

 

That's is a lot of water, there is something very wrong.

 

Just some suggestions.

 

Is this happening on sunny days. If the cratch area is a dark colour it will absorb heat, the internal area the opposite and condensate.

 

Or is this occurring when raining, or all the time.

 

It does look like a big tank so holding a large mass of cold water, lack of ventilation could also be a factor.

 

Just throwing stuff into the pot that might help in diagnosis.

 

Well, we did go to TS and followed the steps asked to, but the builder still wouldn’t address any of the issues. Unfortunately, we cannot really do much more about it. We have made peace with the fact that we can’t count on them and we have to address all the problems ourselves so the ideas and expertise shared here are much appreciated.

 

To be honest we’ve had loads of rain for past couple of months so it’s hard for me to say if it would be a case on a sunny day. And yes the tank is quite big, as a temporary solution I can remove the access cover for the thruster (that is inside the bow locker) and let some air through as the locker itself is vented.

 

Edited January 23, 2014 by Staarek

[smileypete]

.(oops!)

Edited January 24, 2014 by smileypete

[Staarek]

Bit of an update on the dampness issue on my boat. We now have it all sorted, celotex and foam did the trick. I attached couple of pics. The guy that done all the works was not impressed by the state Bluewater left it in and was shocked that we are having this kind of issues in a boat that is 4 months old. Apart from the above, he also modified some of the ventilation arrangements. The tank area is vented from the outside now & the cabin will now also have a vent. It’s been nearly 2 weeks now & it all seems dry! The top of the tank is not covered by drops of water any more as well. The cabin lining is not put back yet as the fitter advised the condition of it is not good enough and I will have to have some new oak veneered ply-wood fitted. There is couple of more issues in the boat that need tackling so I don't think this will be his last visit. Thanks everyone for your input & advice!

 

 

 

Edited February 14, 2014 by Staarek

[Bones]

The update sounds really good. Thanks for the pictures. Was the Celotex glued to to the steel? I ask because I have put some under my front deck and have been concerned about the layer between the steel and the celotex and thought I should glue it....but I don't fancy using glue in such a confined space.

[Staarek]

The update sounds really good. Thanks for the pictures. Was the Celotex glued to to the steel? I ask because I have put some under my front deck and have been concerned about the layer between the steel and the celotex and thought I should glue it....but I don't fancy using glue in such a confined space.

 

It was glued with the foam wherever possible, it seems that it keeps it in place. No other glue was used otherwise.

Edited February 28, 2014 by Staarek