Any solutions for rusty gas locker floor (with holes!)?

[Québec]

Spent part of Xmas day in a DIY shed de-laminating the floor plate of a rusty gas locker on a new (for us) boat suffering from neglect. Dealing with the rust in the gas locker was a requirement of a recent safety inspection. Knew from the amount of crap coming off that there was likely to be a problem. Sure enough, after a thorough scraping and clean a small c. 3mm dia. hole appeared in the centre of the floor plate. Pretty sure there aren't more holes, but they cannot be far away.

 

Know all about the dangers of heavier-than-air LPG leaking into the bilges, and realise importance of getting it right, so would appreciate pointers to/advice on likely solutions. The locker is in the bow; above the waterline; two drainage holes; access via small top hatch; locker sides look to be in good shape apart from the very bottom edges which, however, still look and feel pretty solid even after the thorough scrape.

 

Immediate thought for temporary repair was glass fibre, but also immediately realised that was daft - a) would crack if anything dropped on it b ) nightmare to deal with in terms of future work.

 

Thanks in advance.

Edited December 25, 2009 by quebec

[DHutch]

Well i dont know whats usally done, or even how common it is done.

- Most boats suffer some rust in the gas lockers which are damp and the paint often gets damaged but i think its rair to go through.

 

If the bottom really is totally shot i personally would say the thing to do was proberbly to replace it.

 

If access is easy from the inside of the boat (?) run round the bottom (or half an inch above it) with an angry grinder and cut the old bottom out and have a replacement welded in?

 

 

Daniel

[Québec]

If access is easy from the inside of the boat (?)

 

Apart from the top hatch, the only other way to get access would appear to be to cut a large opening in the bulkhead (which forms one of the locker sides) from the cratch.

 

Does anyone know if a 'mini' locker e.g. a leakproof steel sleeve around the gas canister and placedinside the locker might work & might fulfill safety requirements? Though thinking that one through, presumably if there was a leak the gas would still need somewhere safe to escape to and something to escape through i.e. a pipe to the outside of the boat.

 

I suspect I'll just have to bite the difficult welding option of a new floor plate.

[Keeping Up]

If access for welding is difficult I wonder if it would be acceptable to fit an additional steel floor plate, screwed to the existing one with multiple self-tappers? If it was only a little smaller than the existing one so that the bottles sat on it properly, and you had cleaned the rust from the exiting floor and used plenty of suitable sealant (especially round the edges and round (and down) the screws.

 

I'm just guessing, maybe someone more expert than I could comment.

[ChrisPy]

any replacement bottom plate is likely to be difficult or impossible to fit if the only access is through the top hatch. I found it difficut enough to install a cross beam to anchor the bottles, because the ends of the beam were awkward to reach, with the beam fitted only half way up the compartment. Hold and weld needs 2 hands, but you also need your head in there to see what you are doing. It's not do-able through a typical 50cm square hatch. Even drilling and bolting willl be difficult. It is unlikely that your replacement bottom can be fitted through the hatch (or the cardboard template cut and removed through the hatch).

 

I think we had a similar thread recently.

 

I would be tempted to bash the bottom plate in to make an adequate hole, fill the space below the damaged locker bottom plate with something that will exclude gas (say PU foam) and then cast a concrete slab over the bottom plate, ensuring you maintain the drainage to outside the hull. I think the reason given for not doing this was that collision damage might cause the gas to leak down, but if there is no open air-space for it to enter, the risk is managed.

 

of course, if you can manage the ballasting, just fill the whole space with concrete (even 'lightweight concrete' made with lightweight aggregate instead of gravel/sand) up to the original plate level.

Edited December 26, 2009 by ChrisPy

[NBMike]

Apart from the top hatch, the only other way to get access would appear to be to cut a large opening in the bulkhead (which forms one of the locker sides) from the cratch.

Does anyone know if a 'mini' locker e.g. a leakproof steel sleeve around the gas canister and placedinside the locker might work & might fulfill safety requirements? Though thinking that one through, presumably if there was a leak the gas would still need somewhere safe to escape to and something to escape through i.e. a pipe to the outside of the boat.

 

I suspect I'll just have to bite the difficult welding option of a new floor plate.

 

I fitted a steel box gas locker made to suit cylinder size with a 22mm piece of copper between two tank connectors at box end and outside of boat hull end in a fibreglass cruiser. Any sheet metal place should be able to make one.

Mike

[Martin Kedian]

I fitted a steel box gas locker made to suit cylinder size with a 22mm piece of copper between two tank connectors at box end and outside of boat hull end in a fibreglass cruiser. Any sheet metal place should be able to make one.

Mike

 

 

This is quite a common problem I have ofen solved it by making a new inner which is inserted into the existing one it will need an overboard drain at the bottem but this is quite easily done in pipe welded in on site the old locker floor cand be treated to stabilise the rust problem solved if you would like further info or have a question feel free to PM me or tel 01604511512 best wishes Martin [Kedian Eng Ltd]

[Hairy-Neil]

If the damage really is just the one 3mm hole, why not just weld up the hole?

 

If its beyond this, and I suspect the metal will likely will be thinned elsewhere, then its a candidate for over plating. If the new bottom plate is too big to go in through the hatch, then cut it in half and weld the two bits together once it's in place.

 

As a safety related item this wants to be put right and forgotten. If it's bodged it could come back to bite your arse.

[Tony Brooks]

Spent part of Xmas day in a DIY shed de-laminating the floor plate of a rusty gas locker on a new (for us) boat suffering from neglect. Dealing with the rust in the gas locker was a requirement of a recent safety inspection. Knew from the amount of crap coming off that there was likely to be a problem. Sure enough, after a thorough scraping and clean a small c. 3mm dia. hole appeared in the centre of the floor plate. Pretty sure there aren't more holes, but they cannot be far away.

 

Know all about the dangers of heavier-than-air LPG leaking into the bilges, and realise importance of getting it right, so would appreciate pointers to/advice on likely solutions. The locker is in the bow; above the waterline; two drainage holes; access via small top hatch; locker sides look to be in good shape apart from the very bottom edges which, however, still look and feel pretty solid even after the thorough scrape.

 

Immediate thought for temporary repair was glass fibre, but also immediately realised that was daft - a) would crack if anything dropped on it b ) nightmare to deal with in terms of future work.

 

Thanks in advance.

 

 

I had a new bottom and sides about 6 inches high (6mm thick) made up and then dropped into the locker. Then the sides were welded to the old locker sides (the 6 inches was required because the whole of the foot of the locker was very rusty. Unfortunately the bod the yard chose to do it completely cocked up leaving a drain fitting leaking into a void he left below the new locker floor and thus through the hole into the boat. With 6mm steel in the vulnerable area it should outlast me!

 

Tony Brooks

[Martin Kedian]

I had a new bottom and sides about 6 inches high (6mm thick) made up and then dropped into the locker. Then the sides were welded to the old locker sides (the 6 inches was required because the whole of the foot of the locker was very rusty. Unfortunately the bod the yard chose to do it completely cocked up leaving a drain fitting leaking into a void he left below the new locker floor and thus through the hole into the boat. With 6mm steel in the vulnerable area it should outlast me!

 

Tony Brooks

 

 

Glad you are sorted

[Chris Pink]

As a safety related item this wants to be put right and forgotten. If it's bodged it could come back to bite your arse.

 

Well of course we've got to keep all the fabricators and welders in a job.

 

But I wouldn't spend any money on it.

 

Simply clean up the metal, treat it with paint or suchlike then put down a layer of heavy bitumen compound to make it gas tight, maybe with a 6mm plywood false floor for bulk.

 

a couple hours of work and about 50p

 

depends how many decades you're looking for out of it.

[Hairy-Neil]

a couple hours of work and about 50p

 

You pays your money and take your chance.....

[ditchcrawler]

Spent part of Xmas day in a DIY shed de-laminating the floor plate of a rusty gas locker on a new (for us) boat suffering from neglect. Dealing with the rust in the gas locker was a requirement of a recent safety inspection. Knew from the amount of crap coming off that there was likely to be a problem. Sure enough, after a thorough scraping and clean a small c. 3mm dia. hole appeared in the centre of the floor plate. Pretty sure there aren't more holes, but they cannot be far away.

 

Know all about the dangers of heavier-than-air LPG leaking into the bilges, and realise importance of getting it right, so would appreciate pointers to/advice on likely solutions. The locker is in the bow; above the waterline; two drainage holes; access via small top hatch; locker sides look to be in good shape apart from the very bottom edges which, however, still look and feel pretty solid even after the thorough scrape.

 

Immediate thought for temporary repair was glass fibre, but also immediately realised that was daft - a) would crack if anything dropped on it b ) nightmare to deal with in terms of future work.

 

Thanks in advance.

I have seen this one done by a boatyard and they cut the bows out below the gas locker from the outside, weld a new bottom in and replace the bow bit.

[Phil Ambrose]

Spent part of Xmas day in a DIY shed de-laminating the floor plate of a rusty gas locker on a new (for us) boat suffering from neglect. Dealing with the rust in the gas locker was a requirement of a recent safety inspection. Knew from the amount of crap coming off that there was likely to be a problem. Sure enough, after a thorough scraping and clean a small c. 3mm dia. hole appeared in the centre of the floor plate. Pretty sure there aren't more holes, but they cannot be far away.

 

Know all about the dangers of heavier-than-air LPG leaking into the bilges, and realise importance of getting it right, so would appreciate pointers to/advice on likely solutions. The locker is in the bow; above the waterline; two drainage holes; access via small top hatch; locker sides look to be in good shape apart from the very bottom edges which, however, still look and feel pretty solid even after the thorough scrape.

 

Immediate thought for temporary repair was glass fibre, but also immediately realised that was daft - a) would crack if anything dropped on it b ) nightmare to deal with in terms of future work.

 

Thanks in advance.

 

Again GRP is being maligned, my boat built early 80's has a double gas locker in GRP same as the rest of the boat and gives me no problems whatsoever. Bounced many a bottle on it without problem.

 

Phil

Edited December 26, 2009 by Phil Ambrose

[malbro]

Hi All

recently got my boat safety renewed , delay due to "small gas leak "!!!

As retired Chemical Engineer , this should have been easy but practical experience of small leaks at low pressure

is a special . The way is to pressurize the system with air from ie bycycle pump to say 40inch water ( I did say

retired ) then use foam on brush or spray . There seems to be no problem to purge back to gas , just think , every time u leave the boat , the gas system

will fill with air . H owever if in doubt ,dont try it .

Do not say u have had a gas leak with smell in the boat , could get all your nieghbours on shore .

How did others get on with replacement locker floor ?

Malcolm

[paulcatchpole]

<snip>

 

. The way is to pressurize the system with air from ie bycycle pump to say 40inch water ( I did say

retired )

 

<snip>

Malcolm

 

Worth noting, in case anyone fancies this, that that's 1.5psi. Not 40, or 80, or connect-it-up-to-a-compressor. Surprising things can happen in that sort of situation. H+S risk-assessment job, and local evacuation, on site, if you're going to air-test pipework...

 

37mbar is 0.5psi, there or thereabouts, so the above is 3x normal, plenty enough.

 

PC

[springy]

<snip> Surprising things can happen in that sort of situation. H+S risk-assessment job, and local evacuation, on site, if you're going to air-test pipework...

 

<snip>

 

 

Does that mean I should leave the county next week when we're hydro testing some

pipework to 135 bar g (it is pretty thick wall). Thats over 54 thousand inches of water !

(just under 2000 psi)

 

springy

[paulcatchpole]

Does that mean I should leave the county next week when we're hydro testing some

pipework to 135 bar g (it is pretty thick wall). Thats over 54 thousand inches of water !

(just under 2000 psi)

 

springy

 

Nah, you know as well as I do, that hydraulic testing is far safer than air testing!

 

Sounds exciting all the same...

 

The car engine develops about that on the fuel rail, and when it cracked it was very much an anti-climax... Pssst. Low volume though, of course.

 

PC

[WotEver]

Nah, you know as well as I do, that hydraulic testing is far safer than air testing!

 

Tony