"LPG resistant materials"

[stuart23]

I have a gas locker where the vent is half way down the locker.Reading the BSS I can either put a vent at the bottom of the locker or fill the part of the locker beneath the vent with 'LPG resistant materials'.......Does anyone know what this means...what are 'LPG resistant materials' and is doing this practical with a gap of about 1' ?

[ChrisPy]

I understand that the intention is to fill the space with something that is inert, is not affected by LPG and is non-combustible.

Concrete comes to mind.

I would wrap the bottom of a gas bottle with several layers of polythene and gaffer tape and pour in concrete up to the level of the vent/drain. Remember to remove the bottle before it is cast in solid!

Before doing this it would be essential to ensure the steel will not corrode under the concrete, so I would make sure the internals of the space are well rustproofed and blacked.

 

... others will no doubt disagree

 

 

PS: I believe you have an option to cut the vent drain at and below the waterline and allow the compartment to flood, but you must make sure that there is always a vent slot at the waterline (which may vary depending on the trim of the boat).

Edited August 3, 2010 by ChrisPy

[Timleech]

I understand that the intention is to fill the space with something that is inert, is not affected by LPG and is non-combustible.

Concrete comes to mind.

I would wrap the bottom of a gas bottle with several layers of polythene and gaffer tape and pour in concrete up to the level of the vent/drain. Remember to remove the bottle before it is cast in solid!

Before doing this it would be essential to ensure the steel will not corrode under the concrete, so I would make sure the internals of the space are well rustproofed and blacked.

 

... others will no doubt disagree

 

 

I've done this with the cold 'tarmac' sold in bags by builders' merchants (with the approval of a BSS inspector)

 

Tim

[OldGoldy]

I would wrap the bottom of a gas bottle with several layers of polythene and gaffer tape and pour in concrete up to the level of the vent/drain. Remember to remove the bottle before it is cast in solid!

Before doing this it would be essential to ensure the steel will not corrode under the concrete, so I would make sure the internals of the space are well rustproofed and blacked.

 

... others will no doubt disagree

.....for concrete, substitute expanding foam filler, painted & topped with steel plate to stand gas bottle on??

 

Maybe?

[stuart23]

Couldn't I just fill the bottom of the locker with water?

[WotEver]

Couldn't I just fill the bottom of the locker with water?

Yes.

 

http://www.boatsafetyscheme.com/downloads/...Guide_chap7.pdf Page 12. Section 7.3

 

Tony

 

Quick edit to say as described by Chris Py in post #2

PS: I believe you have an option to cut the vent drain as at and below the waterline and allow the compartment to flood, but you must make sure that there is always a vent slot at the waterline (which may vary depending on the trim of the boat).

Edited August 3, 2010 by WotEver

[blackrose]

I think one problem of using concrete is if water gets into the locker (through the scuppers?) Then you may be faced with a corrosion problem occuring beneath the concrete that you can do nothing about, no matter how well you painted it beforehand.

[stuart23]

I was thinking of filling the bottom of the locker with water.....not cutting a hole for the water from the canal to get in...which then gives me the option of emptying the water out when I want to repaint it...I can't see anything which says I can't do this...

[RLWP]

I was thinking of filling the bottom of the locker with water.....not cutting a hole for the water from the canal to get in...which then gives me the option of emptying the water out when I want to repaint it...I can't see anything which says I can't do this...

 

Don't forget the gas drain holes to let any escaped gas out.

 

Richard

[WotEver]

I was thinking of filling the bottom of the locker with water.....not cutting a hole for the water from the canal to get in...which then gives me the option of emptying the water out when I want to repaint it...I can't see anything which says I can't do this...

I would suspect that the BSS inspector would reason that if you left the boat for a while (or simply forgot to top it up) there's nothing to stop the water from drying out. You then have no LPG resistant material.

 

If you want a wet locker then I believe you have to allow it to 'auto-fill'.

 

Tony

[BEngo]

I would suspect that the BSS inspector would reason that if you left the boat for a while (or simply forgot to top it up) there's nothing to stop the water from drying out. You then have no LPG resistant material.

 

If you want a wet locker then I believe you have to allow it to 'auto-fill'.

 

Tony

 

Tony is correct. However I have a wet locker which fills through a 1"BSP socket welded into the side of the boat. This is large enough to cope with trim change and when I need to clean the locker out and paint inside then it is a simple matter to remove the gas bottles and fit a temporary screw plug so that no more water gets in whilst the locker is being treated.

 

If your boat has a more vicious trim change then a larger socket could be used. they are available up to about 4"!

 

N

[Cris P]

I've done this with the cold 'tarmac' sold in bags by builders' merchants (with the approval of a BSS inspector)

 

Tim

 

Hi. Can you elaborate on this please? Is this a loose tar coated gravel, or does it set hard ?

Thanks.

[ChrisPy]

The socket is to let the water in. I presume you also have a higher hole to let the gas out.

 

David

as I read it, he is hoping to set the hole at the water line. there must be a hole at the water line which is why a vertical slot is best.

[Timleech]

Hi. Can you elaborate on this please? Is this a loose tar coated gravel, or does it set hard ?

Thanks.

 

It does set fairly hard after exposure to the air for a while. It's sold for small patch repairs to driveways etc.

 

Tim

[Cris P]

Hmmm. Sounds like a sticky mess, and, like the concrete, awkward to remove should it be necessary. Would sand be off limits?

[Cris P]

Hmmm. Tricky!

[Proper Job]

Hmmm. Sounds like a sticky mess, and, like the concrete, awkward to remove should it be necessary. Would sand be off limits?

I think sand on its own could be come impregnated with gas?

[WotEver]

I think sand on its own could be come impregnated with gas?

Agreed, plus when you lift the bottle out it'd all fall to the bottom anyway.

 

Tony

[stuart23]

OK...having considered all the possibilities, I'm going to put a false bottom as high up as poss, it will be about 1" above the waterline but when moving it will at times go under the waterlevel...so it will get wet in there . I'll set it so there's a slight angle so any water will drain out ....I'll make sure the drain hole is level with the new bottom...

[Timleech]

OK...having considered all the possibilities, I'm going to put a false bottom as high up as poss, it will be about 1" above the waterline but when moving it will at times go under the waterlevel...so it will get wet in there . I'll set it so there's a slight angle so any water will drain out ....I'll make sure the drain hole is level with the new bottom...

 

Make sure the drain is still exposed when under way.

 

Tim

[starman]

OK...having considered all the possibilities, I'm going to put a false bottom as high up as poss, it will be about 1" above the waterline but when moving it will at times go under the waterlevel...so it will get wet in there . I'll set it so there's a slight angle so any water will drain out ....I'll make sure the drain hole is level with the new bottom...

 

I'm not sure I follow. Do you mean a false bottom (if so what's underneath) or a new bottom? If the latter does that mean you'll need to use smaller gas bottles? I'm trying to solve a similar problem in a tug-style boat where the existing locker is so shallow I can only presume that a previous owner put bottles in on their sides!

[stuart23]

I'm not sure I follow. Do you mean a false bottom (if so what's underneath) or a new bottom? If the latter does that mean you'll need to use smaller gas bottles? I'm trying to solve a similar problem in a tug-style boat where the existing locker is so shallow I can only presume that a previous owner put bottles in on their sides!

 

 

I'm going to put a couple of blocks of wood to support a sheet of metal and then weld the metal at the edges....so there will be a gap between the metal sheet and the bottom of the boat (of about 3")...and then cut a 1" x 3" high vent hole

[furnessvale]

I'm going to put a couple of blocks of wood to support a sheet of metal and then weld the metal at the edges....so there will be a gap between the metal sheet and the bottom of the boat (of about 3")...and then cut a 1" x 3" high vent hole

 

So at the end of the day you are simply making the locker smaller by raising its bottom permanently. I have the same problem on my new tug and in the end I settled on small gas bottles, given the amount I use, rather than a deeper locker below water level. Because the locker is well away from any boat access point, and is protected by an upstand, I always have the option of leaving the lid open and using a taller bottle.

 

George ex nb Alton retired