Explosive Vapours In Our Lockers?

[Aquaria]

The one year old Swan 66 Planeta from Douglas (UK) was on a shake down cruise from the Balearic islands to Sardinia when an explosion occurred 80 miles offshore, reason unknown. Luckily no one got injured, but the yacht was severely damaged. The explosion blew out all hatches in the cockpit area, the contents of the lockers spread all around, the two wheel steering with cabelling went out of function, the connection between hull and deck was partially destroyed. The blast left the yacht without engine, which could not be started any more and the crew was not sure about the strength of the rigging, after the foundation of the back stays were affected by the blast, making sailing impossible.Â*

Worst of all: the blast blew the hydraulic transom hatch/platform open, but still connected to the hull by the hinges Â*and water was finding its way into the boat. The crew managed to remove the destroyed hydraulic arms of the platform Â*and they could pull the hatch back up, screwing it back to the hull and with that reducing the water intake.Â*

As the hydraulic arm of the self steering gear was still in place and functioning and as they were able to install a make shift tiller, they were able to slowly continue their course to the harbour of Oristano/Sardinia, on the last miles accompanied by a SAR-craft and finally pulled in by a fishing boat.

Following investigations regarding the reason for the blast did not show any signs of fire or residues of gasoline, leaving the possibility of a typical gas explosion. ButÂ*Â*the gas installation was fully intact, pressure tests brought up no leaks and wile under way the gas detectors did not get off prior to the blast.Â*

Along with the explosion there was no fire. Â*It was not possible to locate the exact area of the explosion – but as the portside section of the stern was mostly damaged, the blast might have happened in the stowage below.

Insurance company and ship yard believe that a gas explosion took place, triggered by a an electrical sparc igniting a dangerous mixture of gasoline or acetone or a vapour of another source and (air)oxygen in a not well ventilated stowage.Â*

Even though,Â*Â*the spectrum of a dangerous (explosive) mixture between a flammable gas and oxygen is smallÂ*Â*and that it needs a spark to trigger the blast, it made me think of what we have in our cockpit lockers: tin bottles with acetone and thinner, maybe pressure spray bottles with flammable gas for different purposes and maybe the jerry can with a gallon of gasoline for our outboard engine?Â*Â*Â*And aren’t we used to our water tight and almost air tight and therefore smelly lockers?Â*

And in the same locker maybe the engine panel is installed!

What are we doing with our flammable and explosive vapours producing fluids on board? Do we store them professionally?

Source:Â*Â*German yachtingÂ*Â*magazine SEGELN 1/2011 p. 18ff

Uwe

SY Aquaria

[redbopeep]

Scary thing, Uwe.

We keep our paint thinners and such stowed forward in the forecastle. We keep our gasoline stowed away under a shelf in the cockpit (outdoors) and keep welding torch gases in a case adjacent the mainmast. We do have jerry jugs of diesel and kerosene stowed below deck under the cockpit but they do not have the same volatiles as gasoline, etc. I do worry about the small tins of paint thinners and eventually they'll be in a small locker on the foredeck as well but the locker has yet to be fabricated by us! In the meanwhile, I keep a close eye on the fluid-tight bin the are stored in.

[delatbabel]

I don't keep paint thinners on board. In fact I rarely use them at all -- I buy 2 pack epoxy & polyurethane paints, and the brushes tend to be single use. The cost of new brushes for each job is generally comparable to the cost of a tin of thinners.

I have a gas detector behind the stove, and a hand portable one just in case.

I have only diesel down below. Petrol (gasoline) stays up on deck in a jerry jug, with a rope tied to the jug and then over the back of the pushpit to the transom. If anything catches fire on board I grab the jerry jug of gasoline and throw it off the stern of the boat into the water, we can pull it back in when the fire's out.

[redbopeep]

"Paint thinners and such..." ah, we have a small tin of acetone for prepping surfaces in case of using 2 part epoxy (we do have a small 2 part epoxy kit aboard, too, with the thinners) and since we have numerous varnished surfaces we carry a tin of varnish as well as thinner. When I describe our little bin of "thinners and such" I should mention that it includes small tins of paint for topsides as well as the varnish. We carry a tin of tung oil in with the thinners and it is used for oiling the handrails on cabin-top as well as pin-racks and fife-rails. On most boats, these items are stainless or gelcoat and one doesn't have to bother with keeping up with the finishing work. But, on our boat we couldn't possibly go without a goodly supply of volatiles.

At present all of that resides very far forward in the forecastle in the location that was originally the boat's "paint locker" way back when it was built in 1931. One thing the boat had back then which it does not have right now is it's original CO2 engine-room fire suppression system. We retain a halon engine-room fire suppression system aboard (can no longer be serviced in the USA, unfortunately) so we'll shortly have to figure out what to replace it with. Any ideas on that one?

You jog my mind that my "list" of projects for this winter should include the proper paint/thinner locker.

Always somethin'

[Aquaria]

Originally Posted by redbopeep

"Paint thinners and such..." ah, we have a small tin of acetone for prepping surfaces in case of using 2 part epoxy (we do have a small 2 part epoxy kit aboard, too, with the thinners) and since we have numerous varnished surfaces we carry a tin of varnish as well as thinner.Â*Â*When I describe our little bin of "thinners and such" I should mention that it includes small tins of paint for topsides as well as the varnish.Â*Â*We carry a tin of tung oil in with the thinners and it is used for oiling the handrails on cabin-top as well as pin-racks and fife-rails.Â*Â*On most boats, these items are stainless or gelcoat and one doesn't have to bother with keeping up with the finishing work. But, on our boat we couldn't possibly go without a goodly supply of volatiles.Â*Â*

At present all of that resides very far forward in the forecastle in the location that was originally the boat's "paint locker" way back when it was built in 1931.Â*Â*One thing the boat had back then which it does not have right now is it's original CO2 engine-room fire suppression system. We retain a halon engine-room fire suppression system aboard (can no longer be serviced in the USA, unfortunately) so we'll shortly have to figure out what to replace it with.Â*Â*Any ideas on that one?

You jog my mind that my "list" of projects for this winter should include the proper paint/thinner locker.

Always somethin'

... after I read the atricle in the yachting magazine I initially thought, such small amounts of thinners, acetone etc shouldn't be a big risk. But as I inspected the tins, bottles and spray bottles more thoroughly I realized that an awful lot of these gathered in the locker over the years (and we only have a plastic boat!) and even worse, the tin bottles showed signs of corrosion and one spray bottle was even leaking and the aerosole was gone... Â*And adding upÂ* many small amounts stored in a small locker can create Â*big problems in small scale.. for our 32 ft yacht even a small explosion can create a big problem... So, there even is a need for a "paint locker" or a similar safe place on "mainenance free"Â* and small fibreglass boat.

And the other whorry: As we exchanged our diesel engine by an electric motor and therefor use a Honda gasoline electric Â*generator as a back up we carry more gasoline jerry cans on board. And the first season with this new arrangement showed that it is not a good idea to store 4 to 5 gasoline jerry cans (1 Gal /5 litres each) in a locker. We use a stern locker that is fully closed up against the rest of the hull and ventilated by two vents on the deck (Dorade -box) and cockpit coaming, but even though the jerry cans are tested for their purpose (CE-signs etc.) the smell of gasoline is evident. So, we have to find another space with better ventilation, my task for the winter, but not an easy one on a 32ft boat though... Â* Too bad that "paint lockers" are out of fashion.Â*

And regarding your halon engine-room fire suppression system: At least in the EU they are banned since the end of 2003 due to the vast negative impact of halon to the atmosphere ( sourceÂ*: little off topic but interesting to read about the reactions on the EU regulations mandating the decommissioning of all halon systems...and after reading the whole 54 pages you are an expert in fire extinguishing systems...).Â*

Uwe

SY Aquaria