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Sealing a cable entry point


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There are a couple of places where groups of cables pass through the bulkhead between the engine bay (under my cruiser stern deck) and the back cabin. Each consists of a plastic bulkhead fitting, with some dozen or so cables of various sizes passing through.

 

Can anyone suggest a way of making these gas-tight so that engine smells don't leak through into the cabin? I don't want a solution that would prevent me from adding or changing cables in the future.

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36 minutes ago, Keeping Up said:

There are a couple of places where groups of cables pass through the bulkhead between the engine bay (under my cruiser stern deck) and the back cabin. Each consists of a plastic bulkhead fitting, with some dozen or so cables of various sizes passing through.

 

Can anyone suggest a way of making these gas-tight so that engine smells don't leak through into the cabin? I don't want a solution that would prevent me from adding or changing cables in the future.

Try a search for 'Cable Transit Blocks' Used in the offshore industry for running cables from hazardous to non hazardous areas, fire and gas proof.

 

All sorts of combinations and sizes available.

 

https://www.hawke-hts.com/ext/fi/17/hts_catalogue_september_2012.pdf

 

Image result for cable transit blocks

Edited by Alan de Enfield
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5 hours ago, Keeping Up said:

There are a couple of places where groups of cables pass through the bulkhead between the engine bay (under my cruiser stern deck) and the back cabin. Each consists of a plastic bulkhead fitting, with some dozen or so cables of various sizes passing through.

 

Can anyone suggest a way of making these gas-tight so that engine smells don't leak through into the cabin? I don't want a solution that would prevent me from adding or changing cables in the future.

I just use a soft mastic and push it out on the very rare occasion I want to add a new cable, then fresh gunge in the hole.  Works for me.

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On 31/07/2019 at 17:47, BEngo said:

Henley's Compound is the stuff.  Made for this sort of job. Probably yellow best but green would be OK too.

N

Crikey, there's a blast from the past! I'm not doubting your recommendation, I'm just surprised they're still making it. 

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25 minutes ago, Johny London said:

I'm surprised boats don't have to have something suitable by law. Mine just has a big round hole cut in the steel, it;s a bit jagged too, not even an edging band on it - and that's from brand new. Definitely on my to do list.

Why law. 

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27 minutes ago, Johny London said:

I'm surprised boats don't have to have something suitable by law. Mine just has a big round hole cut in the steel, it;s a bit jagged too, not even an edging band on it - and that's from brand new. Definitely on my to do list.

It is a BSS requirement that the cable should be protected when passing thru bulkheads.

 

All electrical cables must be:
• located where they will not be susceptible to impact or
abrasion damage; or,
• supported away from any structure or item of equipment
likely to cause impact or abrasion damage; or,
• contained in a conduit or cable tray supported away from
it.
Cables passing through bulkheads or structural members must
be protected against chafing damage by the use of grommets,
sleeves or sealant used effectively.

Cable conduit or cable trays must be free of signs of
overheating or damage.

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Well that's something at least , though as I said mine just come through a jagged hole - it was like that from brand new and of course came with a certificate of conformity. The bss inspector didn't pick up on it either (mind you, I think he gave up looking when he realised it was a "new" boat because surely everything "must" be ok already?).

Never fails to amaze me the sloppy standards and generally accepted low quality of all things boat. Gradually I'm getting round and making everything excellent though. Gradually.

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9 minutes ago, Johny London said:

Never fails to amaze me the sloppy standards and generally accepted low quality of all things boat.

And more particularly BSS inspectors.

 

As I mentioned at the time, my last BSS took 14 minutes and was conducted from sitting in the saloon.

More than 5 minutes of that was trying to find the registration number in the on-line records.

 

He said "it passed last time, so we'll work on it being OK this time - I see you have Co detectors so that is covered".

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This sort of attitude seems to be endemic in boating. Not saying there aren't a few good guys out there.

It was like when they were showing me where the water went, and there was a little chain to keep you from miss placing the plug. "Oh the chain always breaks on these after about the first or second time." And it did. So why doesn't the manufacturer do something about it. Prolly cos that's the way they've always done em....

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9 minutes ago, Johny London said:

This sort of attitude seems to be endemic in boating. Not saying there aren't a few good guys out there.

It was like when they were showing me where the water went, and there was a little chain to keep you from miss placing the plug. "Oh the chain always breaks on these after about the first or second time." And it did. So why doesn't the manufacturer do something about it. Prolly cos that's the way they've always done em....

But if everybody kept claiming a new one on warranty they would, but probably no one has.

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6 hours ago, Johny London said:

So that dangerous fumes can't get in (in event of leaking exhaust?) Or water if the worst comes to the worst? Or fumes from a fire? Noise, diesel smells. Just saying like.

My engine like many others in inside the boat, I walk past it to get from the bed to go to the loo. It doesn't fill my boat with deadly fumes.

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Now that I have a small positive pressure in the engine bay, since I installed a bilge-blower fan that keeps it cool especially around the domestic alternator, even though the engine is effectively fume-free I do suffer from a problem now that the batteries are getting old and therefore more prone to giving off gases. The gases get blown through to the cabin and although I doubt that they pose a real hazard, they do set off the gas alarm that has a sensor in the back cabin. I can of course cure the problem by switching off the alarm but I'd much prefer to cure it by keeping the gases out of the cabin.

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The problem is how to ensure that the filler, whatever it is, gets between all the cables. It's easy to seal around the outside but that isn't good enough. A liquid would do it, but then if it stays liquid it will run away but if it solidifies it isn't removable.

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13 hours ago, Keeping Up said:

Now that I have a small positive pressure in the engine bay, since I installed a bilge-blower fan that keeps it cool especially around the domestic alternator, even though the engine is effectively fume-free I do suffer from a problem now that the batteries are getting old and therefore more prone to giving off gases. The gases get blown through to the cabin and although I doubt that they pose a real hazard, they do set off the gas alarm that has a sensor in the back cabin. I can of course cure the problem by switching off the alarm but I'd much prefer to cure it by keeping the gases out of the cabin.

Doesn't the effectiveness of a bilge blower depend on it exhausting overboard? I realise you're using one for cooling rather than fume extraction, but there's read across regarding the ingress and egress needing to balance.  If the air going in struggles to get out, your cooling flow (or fume extraction) is sub optimal.

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14 minutes ago, Sea Dog said:

Doesn't the effectiveness of a bilge blower depend on it exhausting overboard? I realise you're using one for cooling rather than fume extraction, but there's read across regarding the ingress and egress needing to balance.  If the air going in struggles to get out, your cooling flow (or fume extraction) is sub optimal.

Actually there is quite a large ventilation grille in the control column near the back of the engine, but the air from it used to go straight to the engine intake leaving the rest of the bay, especially near the front of the engine, to get rather warm. The bilge blower takes air from outside and blows it on the alternator at the front of the engine; by the time the air has reached either the engine inlet or the vent grille it has cooled things quite considerably. The positive pressure is therefore quite small but it is positive rather than negative and so the air will get out wherever it can.

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