Barge bilges - are there any ideas for ventilation and or sealing bilges.

[Alistair1357]

I recently discovered some mould in the back of a cupboard - it's against the lining of the cabin about a couple of inches above the floor - behind the lining is a gap between the edge of the floor and the spray-foam insulation. I think the cold air in the bilge is causing condensation to form in this area, leading to the mould. 

 

So, I have some questions...is this gap to allow ventilation to the bilge - what would happen if I closed this gap with more spray foam? - just the area behind the lining of the cupboard - bear in mind the other side of the barge would still have the opening. Would it be better to have vents in the cupboard panels to draft more air through this area? Or both? It's easy to remove and attach the cupboard and lining for access. 

 

The other thought I had was in how the bilges are constructed - reinforcing cross-members span the bottom plate - channels are cut to allow water flow to the rear of the vessel - for water...but the top of the cross member is used as a platform to support a batten that supports the floor - the battens, as far as I can ascertain are not notched to allow air to circulated - so each reinforced "cell" between the supports does not have good air-flow barring the side sections, which as I have mentioned allow the cold air to cause mould on the cabin lining inside the cupboard...

 

What about sealing the entire interior floor section - airtight, then dropping in Argon gas to prevent mould and as an anti-rust? I imagine it would be simple enough to fit a membrane under the floor, with a gas valve to introduce the Argon? Because Argon is heavier than air, it should stay there and topping up would be a simple affair, when needed? Any thoughts?

[David Mack]

 

[36national]

The Argon thing wont work. Argon is also a constituent of air but it doesn't all sink down into your bilge.

[Alistair1357]

4 minutes ago, 36national said:

The Argon thing wont work. Argon is also a constituent of air but it doesn't all sink down into your bilge.

You might be thinking of Nitrogen?

[blackrose]

6 minutes ago, Alistair1357 said:

You might be thinking of Nitrogen?

 

Nitrogen is inert and non-reactive but won't sink either. 

Edited January 23, 2022 by blackrose

[36national]

No I'm thinking of Argon. It varies slightly but Argon is usually estimated to  make up 0.9% of atmospheric air and it doesn't all sink to the ground.

[Alan de Enfield]

Just now, blackrose said:

 

Nitrogen won't sink either.

 

Radon does ' quite common in cellars in some parts of the country.

Problem is it is a 'make you glow in the dark gas' so not a good choice.

[TheBiscuits]

Just now, Alan de Enfield said:

 

Radon does ' quite common in cellars in some parts of the country.

Problem is it is a 'make you glow in the dark gas' so not a good choice.

 

Filling the bottom of the boat with any non-breathable gas sounds like a complicated suicide attempt.

[Jen-in-Wellies]

Good luck trying to make the bilge gas tight. The international space station has a budget of billions and loads of very clever rocket scientists and it still leaks air. You'd need some make up gas in to the bilge, with some way to control it. Any mistake, or failure and suddenly the boat is filled with something unbreathable.

[36national]

at least Nitrogen would be cheaper.

[Alan de Enfield]

Hydrogen would be more fun (ask Graf Zeppelin) and may even help the boat to get thru the shallow waterways.

[TheBiscuits]

Just now, Alan de Enfield said:

Hydrogen would be more fun (ask Graf Zeppelin) and may even help the boat to get thru the shallow waterways.

 

Keeping it in the bilge could be tricky.  Unless you roll the boat upside down!

[36national]

Radon doesn't accumulate in cellars because it sinks. It accumulated in cellars and other subterranean places because it is created in the ground. 

you could get through the shallows ok but not under the low bridges

 

[Alan de Enfield]

Just now, 36national said:

Radon doesn't accumulate in cellars because it sinks. It accumulated in cellars and other subterranean places because it is created in the ground. 

 

I know - I had a house which had to be radon-proofed.

 

However radon is far heavier than air (7.5 times actually) so if you put it in a hole it will not rise and disperse in the air. It tends to only move around the house if you have a forced air heating system.

[blackrose]

9 minutes ago, 36national said:

No I'm thinking of Argon. It varies slightly but Argon is usually estimated to  make up 0.9% of atmospheric air and it doesn't all sink to the ground.

 

I think your idea of sealing the area and pumping argon down there sounds overly complex. Try increasing ventilation to the area first.

 

By the way, the gap between the hull sides and wooden lining isn't strictly necessary. Some people will tell you it helps ventilate the bilges, but on most boats it's a closed space and filled with still air so it doesn't really perform any function. Removing the gap by filling it with insulation is possible and won't create a problem in the gap because the gap won't exist any more. However, if you fill it only do that because you want to improve the insulation, not because you want to eliminate condensation, because that won't necessarily work. A well insulated area of the interior below the waterline can still get cold and moisture in warm air which reaches a cold surface can still condense on the surface.

 

In short, ventilation is your best bet.

 

 

 

[Alistair1357]

16 minutes ago, Jen-in-Wellies said:

Any mistake, or failure and suddenly the boat is filled with something unbreathable.

That would certainly end my boating days...or all my days. 

 

[Tony Brooks]

I think investigating ventilating them would be better but disruptive. If an electric compressor 12V fridge cut holes in the floor under the "radiator" and use computer fans to blow cold air up over the evaportaer when the compressor is running. there is normally a terminal on the control box.

 

More disruptive would be to trunk ventilation ducts from the bilge to above rear exit level (assuming a cruiser or semi-trad) to vents in the engine  room. Then similar at the front of bulkhead. Whenever the engine is running it is likely to suck air through the bilge. If you have solar then you could power computer fans in the vents from the "load" terminals om the controller.

[john.k]

I saw a show on telly about affordable  alternative living,and there was a canalboat some young people bought for a few hundred quid.....what I thought odd,was the bilge seemed to be completely bricked in ,not loose bricks,but bricks cemented together ,like a driveway.....ballast ,I suppose.

[Tony Brooks]

3 hours ago, john.k said:

I saw a show on telly about affordable  alternative living,and there was a canalboat some young people bought for a few hundred quid.....what I thought odd,was the bilge seemed to be completely bricked in ,not loose bricks,but bricks cemented together ,like a driveway.....ballast ,I suppose.

 

Yes,and some used poured concrete from new, not a bodge for a bad hull. One I say had some sort of tarmac topping to  form the floor. Other have had loose ballast (sand & stones). Neither of these are a good idea and might cause premature perforation.

Edited January 23, 2022 by Tony Brooks

[David Mack]

3 hours ago, john.k said:

I saw a show on telly about affordable  alternative living,and there was a canalboat some young people bought for a few hundred quid.....what I thought odd,was the bilge seemed to be completely bricked in ,not loose bricks,but bricks cemented together ,like a driveway.....ballast ,I suppose.

In the Narrowboat Builders Book, Graham Booth comments that the brick-paving look of the newly laid ballast seemed to fit with the cheap plastic patio table and chairs that they had on board for the cruise of their sailaway from the boatbuilder to home.