Rockwool insulation?

[dmr]

3 hours ago, David Mack said:

How?

Thats interesting?   You can get "anti condensation paint" which I always thought was snake oil. We used to get loads of winter condenastion on the lower cabin sides below the floor in the back cabin, and on top of the integral fuel tank. The steel was sprayed in ordinary paint by the shell builder, and I had gone over a lot of it with Danboline. In the spring I redid the whole lot in Jotun 90, put on very badly and thickly with an old long handled brush, so quite a textured surface. It appears that I am now getting less condensation. Does surface texture have an influence???

[5239]

6 minutes ago, dmr said:

Thats interesting?   You can get "anti condensation paint" which I always thought was snake oil. We used to get loads of winter condenastion on the lower cabin sides below the floor in the back cabin, and on top of the integral fuel tank. The steel was sprayed in ordinary paint by the shell builder, and I had gone over a lot of it with Danboline. In the spring I redid the whole lot in Jotun 90, put on very badly and thickly with an old long handled brush, so quite a textured surface. It appears that I am now getting less condensation. Does surface texture have an influence???

I reckon a textured surface can possibly reduce condensation,

I couldn’t explain through any scientific reasoning but experience tells me it could be so 

 

[David Schweizer]

1 hour ago, Tonka said:

Only advisory now on private boats. Think it is compulsory on commercial boats including hire

I am certain it was compulsory when we bought the boat, so it already had all the legally required ventilation. It worked well and there was no need to remove it.

[Tonka]

Just now, David Schweizer said:

I am certain it was compulsory when we bought the boat, so it already had all the legally required ventilation. It worked well and there was no need to remove it.

I think it was when the BSS started as we had to put extra vents in the bottoms of the front and rear doors on our previous narrowboat. But now it is only advisory

[magnetman]

Yes ventilation was compulsory for quite a few years after the BS scheme started.

Now advisory. 

 

 

[Alan de Enfield]

5 minutes ago, Tonka said:

I think it was when the BSS started as we had to put extra vents in the bottoms of the front and rear doors on our previous narrowboat. But now it is only advisory

 

I think they were 'reminded' that they cannot write requirements that affect 'individuals and that it is not illegal to commit suicide, BUT they can write rules / requirements for 3rd parties who are paying for the use of the boat, ie comercial boats, hire boats etc.

 

If you read the BSS requirements you'll see that quite a lot of it is 'advisory only' (for private boats) and not only includes the ventilation, but all of the 230v AC systems.

They cannot refuse to issue a BSSC if your wiring is dangerous, or you can asphyxiate yourself if you have no vents.

 

The BSS is to protect passers by and other boaters from your boat exploding, bursting into flames etc., it is not there to protect the boat owner.

 

Our role in supporting navigation and harbour authorities, is to help reduce the risk of boat fires, explosions, carbon monoxide or pollution from boats harming visitors to the inland waterways, the waterways' workforce, other waterways users and property on or alongside the waterways.

[Gybe Ho]

55 minutes ago, dmr said:

Does surface texture have an influence???

 

 

Maybe condensed droplets find it easier to revapourise by springing off a solid point on the surface, a different version of the Teflon saucepan coating effect? Just a guess. 

12 minutes ago, Alan de Enfield said:

 

The BSS is to protect passers by and other boaters from your boat exploding, bursting into flames etc., it is not there to protect the boat owner.

 

 

One of the more enduring forum group-think myths.

[ditchcrawler]

2 hours ago, David Schweizer said:

But surely boats are legally required to have permanent ventilation via low level cabin side/door vents and roof ventilators. We had both and more than the regulations required, our cabin was always dry.

No , not private boats 

58 minutes ago, magnetman said:

Yes ventilation was compulsory for quite a few years after the BS scheme started.

Now advisory. 

 

 

Over 25 years ago it was advisory from when I first looked into the BSS requirements 

[Tonka]

1 hour ago, Alan de Enfield said:

 

I think they were 'reminded' that they cannot write requirements that affect 'individuals and that it is not illegal to commit suicide, BUT they can write rules / requirements for 3rd parties who are paying for the use of the boat, ie comercial boats, hire boats etc.

 

If you read the BSS requirements you'll see that quite a lot of it is 'advisory only' (for private boats) and not only includes the ventilation, but all of the 230v AC systems.

They cannot refuse to issue a BSSC if your wiring is dangerous, or you can asphyxiate yourself if you have no vents.

 

The BSS is to protect passers by and other boaters from your boat exploding, bursting into flames etc., it is not there to protect the boat owner.

 

Our role in supporting navigation and harbour authorities, is to help reduce the risk of boat fires, explosions, carbon monoxide or pollution from boats harming visitors to the inland waterways, the waterways' workforce, other waterways users and property on or alongside the waterways.

So why they don't use that reason to remove boats that have no index number or name shown so can't prove they have  a safety certificate is worrying 

[Alan de Enfield]

20 minutes ago, Tonka said:

So why they don't use that reason to remove boats that have no index number or name shown so can't prove they have  a safety certificate is worrying 

 

You'd have to ask the BSS that, but probably because the BSS does not have the right to remove boats.

 

Maybe the question would be better asked of C&RT who already have the power to remove boats without a BSSC (as they are not complying with the licence requirements).

[blackrose]

Rockwool + vapour barrier between it and the interior of the boat is fine, although to get the same insulation properties as an inch of sprayfoam, Cellotex or Kingspan board, the rockwool is going to have to be a lot thicker. Rockwool without a vapour barrier is a bad idea for the reasons already described.

 

I'm still not sure why the OP has bare steel in their cabin? 

8 hours ago, magnetman said:

People tend to assume Rockwool absorbs moisture because it looks like it would be it doesn't. 

 

Really? I don't think people assume rockwool absorbs water. You've rather missed the point. People correctly assume that without a vapour barrier rockwool will allow moisture in the air (and there's always moisture in warm air) to pass though and condense on the cold steel hull. That's the issue. It's not about absorption, it's about transmission.

Edited February 22 by blackrose

[Machpoint005]

9 hours ago, magnetman said:

 

People tend to assume Rockwool absorbs moisture because it looks like it would be it doesn't. 

 

Rockwool is hydrophobic. 

 

It will not absorb moisture from the air. 

 

 

 

It's also completely incombustible. 

 

Unlike plastics, which burn and emit highly toxic smoke. 

 

The disadvantage is that you need a greater thickness of Rockwool to provide a given level of heat insulation, but bear in mind that the material, whatever it is, does not insulate. It's the trapped air that does the work. Plastic foam is better at trapping those little pockets of air. 

 

 

 

 

[Arthur Marshall]

I used rockwool to fill the odd gap in the insulation boards and some gaps under the windows. Unfortunately it may not absorb water but it does hang on to it once it gets wet and when i had a window leak it wound up causing a bit of rust and a fair bit of rotten wood.

[Rebotco]

I am wondering if there is confusion between the old "Fibreglass" and the more modern "Rockwool"?

[Tonka]

12 hours ago, Rebotco said:

I am wondering if there is confusion between the old "Fibreglass" and the more modern "Rockwool"?

Ones built from glass and the others not.

No confusion by me

[NEBUCHADNEZZAR]

I can only speak from experience, when I built my boat 4 yrs ago I used 2 types on insulation in thr walls and ceiling. I first sprayed expanding foam to a depth of around 2 inches then lined with rock wool to a thickness of 3 inches. In 4 years I've never had a problem with either condensation or heat loss.

[Tonka]

9 hours ago, NEBUCHADNEZZAR said:

I can only speak from experience, when I built my boat 4 yrs ago I used 2 types on insulation in thr walls and ceiling. I first sprayed expanding foam to a depth of around 2 inches then lined with rock wool to a thickness of 3 inches. In 4 years I've never had a problem with either condensation or heat loss.

Have you a thermal imaging camera to prove that you do not have heat loss?

[NEBUCHADNEZZAR]

Hi, there is always heat loss because the thickness of the walls and roof is limited. However I find it comfortable enough. After heating it will retain that for most of the night and likewise during the summer it stays cooler for a long time inside. Installation of my double glazing made the biggest difference.

[Gybe Ho]

10 hours ago, NEBUCHADNEZZAR said:

...  I first sprayed expanding foam to a depth of around 2 inches then lined with rock wool to a thickness of 3 inches. In 4 years I've never had a problem with either condensation or heat loss.

 

Sounds like a proper job, the 2" of spray foam deals with the risk of cabin moisture wriggling through the rockwool and condensing at the cold metal hull/rockwool interface. Did you apply any additional measures such as a membrane to keep moisture out of the cabin lining? 

[koukouvagia]

See this post. Slab insulation + vapour barrier.  It's been condensation free for about twenty years.

Best Low Cost Insulation - Boat Building & Maintenance - Canal World

 

 

When I was looking for my earlier posting I used ChatGTP just to see what came up.  Here is the result, which I thought was quite fair.

 

 

ChatGPT said:

In the Canal World Discussion Forum, the user 'koukouvagia' has shared [his] insights on using slab insulation combined with a vapour barrier to prevent condensation on boats. They emphasize the importance of a continuous vapour barrier to keep the insulation dry, noting that their installation has remained condensation-free for about twenty years.

canalworld.net

In a 2020 discussion, 'koukouvagia' confirmed the effectiveness of this method, stating that it resulted in no condensation issues.

canalworld.net

These experiences suggest that properly installed slab insulation with a continuous vapour barrier can effectively prevent condensation on boats.

Edited March 13 by koukouvagia

[Gybe Ho]

43 minutes ago, koukouvagia said:

When I was looking for my earlier posting I used ChatGTP just to see what came up.  Here is the result, which I thought was quite fair.

 

 

I have started using Perplexity.ai in the past 6 weeks for narrowboating questions, it is impressive. However these agents still need to be treated with caution.

 

At Perplexity.AI the following 3 questions produce interesting but confusing results that only @cheesegas could decipher.

1. Does the Victron Lynx Smart shunt have a remote switch?
2. Does the Victron Lynx shunt have a remote switch?
3. Does the Victron shunt have a remote switch?

[David Mack]

4 hours ago, Gybe Ho said:

 

I have started using Perplexity.ai in the past 6 weeks for narrowboating questions, it is impressive. However these agents still need to be treated with caution.

 

At Perplexity.AI the following 3 questions produce interesting but confusing results that only @cheesegas could decipher.

1. Does the Victron Lynx Smart shunt have a remote switch?
2. Does the Victron Lynx shunt have a remote switch?
3. Does the Victron shunt have a remote switch?

But AI can only work with the material it has been trained on. So it could be a case of GIGO - garbage in garbage out.  And over time more AI output is going to be out there and feeding into the AI engines, meaning the garbage gets reiterated as truth, and rarely going back to verified accurate or peer-reviwed source material.

[Gybe Ho]

3 hours ago, David Mack said:

... meaning the garbage gets reiterated as truth, and rarely going back to verified accurate or peer-reviwed source material.

 

Sounds like an RCR/RCD thread on this forum, plenty of human authored raw material to confuse an AI bot on that subject