Wondering about where to put propane sensors...

[Sailormann]

So I've decided to throw caution to the winds and stick with a propane stove. Bought a new control system with two propane leak sensors. Sensors aren't the greatest looking things in the world, so would like to put them in an unobstrusive place.

The propane locker on the boat is aft center, and properly vented overboard. One of the sensors is going to go in the cockpit locker underneath, and near the propane locker, and I am thinking that the best place for the second one is near the stove in the galley area. I want to put it under and almost behind the stove, in the molded-in recess, but I am not sure if that will be effective if gas starts spewing out of the oven, as it will leak forward - not aft towards the sensor.

Does anyone have any knowledge/experience with this. I'm a propane newbie and the stuff makes me a bit nervous....

[sailingdog]

Sailormann-

I would put it forward, away from the stove. Some gas leaks are inevitable, since there are times you won't burn all the gas when lighting it... what you want is the sensor to tell you if the propane is gathering in the cabin... placing it near the stove is going to give you a lot of false alarms... since LPG is kind of going to be present, in at least some small quantities, right near the stove. Putting the sensor down low, near the front of the cabin will warn you if the levels in the boat are becoming a danger...and IMHO be far more useful.

[tdw]

Surely your sensors should simply go in the lowest part of the bilge ? Propane, is heavier than air so any significant amount will settle in the bilge.

To my mind the most important part of any gas installation is the line switching. Most people use a Solonoid, switch activated from the cabin, but I hear too many folk complaining about solonoid failure.

When we went gas we ignored the fitting of a solanoid and simply put a pressure gauge on the line. This gauge is visible from the companionway hatch. If it falls below a certain level you know you have a leak. Bottles are turned on and off at the bottles themselves. Yes that is inconvenient but it's a small price to pay as far as we are concerned. Turn bottles on when you start to prepare a meal, turn off at end, safe as safe can be.

[Sailormann]

Appreciate the input from both of you. I am thinking that there might be something to the false alarm thing but we don't have a lot of things to mount on. The galley is made up of a lot of individual components that fit together with spaces of about 1/2 to 1/4 inch between them - basically inaccessible

The bilges on the boat are the shallowest I have ever seen - the deepest part of the bilge is right in the center of the cabin, and it is 4 inches deep, so there is not enough space to put a sensor, as they cannot get wet.

So I guess I'll go a little further from the stove and maybe stick it inside the locker under the sink - about 6" up from the hull.

Does anyone know how much propane it takes to blow up a boat ??? (seriously)...

[sailingdog]

Sailormann-

I don't think it should be in the bilge... but in the cabin, mounted on a a bulkhead or such forward, near the mast. My bilge is probably a bit shallower than yours, being two inches deep or so...

A 1 lb. tank, like you would use for a camping stove or propane torch is plenty of fuel to blow up a boat. The explosive concentrations of propane range from 2.4-9.5% of the atmosphere by volume IIRC. If your cabin has a volume of 600 cubic feet, you'd only need 14.4 cubic feet of propane to make it explosive. Also, fuel-air mixtures are capable of the largest, most powerful explosions after nuclear weapons... the US has used their largest FAE bombs to clear entire minefields...

The amount of butane contained in a cigarette lighter re-fueling canister (2.5 oz.) is more than enough to be dangerous.

[Sailormann]

Well ... I am going to have to be VERY careful with this propane stuff - weird - have been on lots of boats that have it, never given it a second thought. Never known or even met anyone who has had a problem with it, but now that it's MY boat - I am concerned...