Aux Gas tank

Hightower · 14 May 2004, 00:31

Am fitting aTempo Aux fuel tank into one of my seat pods and was wondering if the seat pod should have a couple of vents (one either side) to stop a build up of petrol vapours inside the seat, do you think it's a good idea or should I not bother?

Andy

tim griffin · 14 May 2004, 06:55

A very good idea
regards tim
www.griffmarineservices.co.uk

Keith Hart · 14 May 2004, 08:50

I'm not so sure of that Tim.

I think that petrol storage containers (not the pertrol tanks themselves, but the metal boxes they are kept in) do NOT have vents. I think that the idea is to contain the flammable vapours so there is less risk of explosion.

We could do with hearing from someone who is well up on the petroleum storage regulations on this matter.

I think most people just strap the aux tanks to the deck so the vapour would probably be too dispersed to cause a problem. It is the 15:1 air/fuel ratio that causes the problem, anything over or above and the vapour will not ignite. I have seen a lighted cigarette plunged into a full tank of petrol and the cigarette went out! DO NOT TRY THIS AT HOME, it was done under strictly controlled circumstances by experts on one of my fire investigation courses at the Fire Service College.

Keith Hart

Dirk Diggler · 14 May 2004, 09:13

If boat builders adhered to the "petroleum storage regulations", you lot wouldn't be able to have motor powered boats.

A couple of years ago the owner of the fuel barge in Poole Harbour campaigned to have the carrying of fuel in a boat banned on the highways. His reasoning was that it's illegal to carry more than 10 litres or so in a portable tank/can!!!

If the tempo tank has the facility for a breather hose then connect it to a breather outlet, otherwise a vent of some sort should be fitted as low as possible to the seat pod.

Basically, if you have fumes, get rid of them!!

Rupert Bear · 14 May 2004, 10:11

I fitted a plastic 70lt tank under my seat. I put a breather valve on the back of the seat connected by a hose to the breather outlet on the tank. To make sure I didn't get fume build up I put a shell vent low down to get rid of petrol fumes (heavier than air) and another high up to get rid of any battery gas (lighter than air) and sealed the bulkhead between.
Nothing has blown up yet

Hightower · 14 May 2004, 20:17

Thanks for the advice Gents. I really didn't want to mount the tank in the seat pod as it takes up a lot of room. That really left deck mount, but me being a neat and tidy sort of person didn't want surface clutter, the other reason being out of sight out of mind when I was moored or tied up alongside a pontoon.

If I did go surface mount do I have to worry about the sun being on the tank?

Andy

Jari Hjerppe · 14 May 2004, 20:41

If the tank is in the direct sunlight the temperature in the tank will increase, quite a lot if hot day, and that will increase the pressure inside the tank if the breather is closed. Keep the breather open in the sun!

Jari

Daniel TD5 · 15 May 2004, 18:29

my vailant v450 came with a 5 gallon tank plastic type mounted under the
seat. that were its ment to be fitted both sides of the seat have air vents low down fitted as standard the tank as a vent on it for when in use i allso would
like to put a spare tank in place say 5 gallon i would just fit it next to the exsiting one i would think that putting them under seat would be the best place for them as on deck they could get damaged i think were the battery
is fitted is more important as some boats i have see have them next to the fuel tank

Hightower · 15 May 2004, 20:33

Yeh and you wouldn't want to throw you flares in there by mistake either!

Was looking at the layout today and was thinking along the lines of between the rear seat pods, strapped to the deck with some form of cover over the top. Wouldn't have to be water tight and should have plenty of ventilation as well.

Andy