Most yachts use gas for cooking as it’s a very convenient fuel for this purpose. However its use also comes with a range of safety issues that must be addressed – the potential dangers of having gas on board mean it’s crucial to be certain the entire system is maintained in a bullet proof condition.
The problem is that both the common fuels used for bottled gas – butane and propane – are heavier than air. This means that any gas that leaks from the system will stay within the boat, collecting in the bilge, until the point at which an explosive concentration builds up (see 10 boating disasters and how to avoid them).
Installing a gas alarm is therefore a sensible precaution. They are triggered at concentrations that are significantly lower than an explosive mix of gas and air and sensors can be positioned under gap burning appliances such as the cooker, as well as in a dry part of the bilge.
However, a gas alarm is not a substitute for a properly installed and maintained gas system that complies with the current best practices. This can be a particular problem for owners of older boats, as acceptable standards have changed over time, in much the same way that our attitudes to other safety related matters on board have also changed. Even where the gas systems of older vessels have at some stage been updated, the work was not always done to a high enough standard to withstand decades of use, and may need to be overhauled, or even replaced.
Elements of the system
The basic elements of the system include a dedicated gas locker with a drain that leads overboard to allow any gas that might escape to drain away harmlessly outside the vessel. In addition, each bottle must be lashed down to prevent movement at sea.
The bottles should be connected to the system via a regulator with an on/off valve and a short length of flexible hose. A solid copper pipe should then be used to for the main run of pipe. This needs to be supported at intervals of around 30cm and protected by sleeving where it passes through bulkheads.
A second length of flexible hose should run between this copper pipe and a gimballed cooker. This needs to be long enough to allow the cooker to swing freely, without tension on the hose, even with the boat at very high angles of heel. Finally, gas burning appliance should ideally be equipped with flame failure devices that cut the supply if the flame is blown out, plus an isolator valve near the appliance.
It’s also worth fitting a bubble tester within the vented gas locker. This is a simple device that can be used to periodically test the gas-tight integrity of the system. Another common addition is a solenoid operated valve on the regulator, so that the gas can be turned on and off without having to go on deck to do so.
Even the best installations need periodic maintenance to ensure they remain in good condition. A monthly visual inspection of the condition of the flexible hoses is a good place to start. At the same time, if a bubble tester is fitted this can be used to check for potential leaks, and the test button on the gas alarm activated to check the unit is still operating properly.
Flexible hoses and regulators have a finite life: hoses should replaced within five years of the date of manufacture marked on the hose, or as soon as any signs of cracking, abrasion or kinking are evident. Regulators should be replaced at 10-year intervals. In both cases this is a quick process that involves well under an hour of labour and only a few pounds worth of parts, yet the number of yachts with decades-old regulators and flexible pipes is astonishing.
Problems can also be found with the copper gas pipe. Unlike a copper gas pipe in a house, there is always movement on a yacht, which can create problems where the pipe passes through bulkheads and at the ends, where repeated bending can cause the metal to fracture.
With older yachts it’s also worth analysing the design of the installation carefully. It’s only in the last couple of decades that all new boats have been fitted with a dedicated draining gas locker. While many older boats were equipped in a similar way, there are plenty of examples in which a gas locker was retrofitted with a standard of workmanship that may not stand the test of time, or even drains installed in a manner that poses a risk of sinking.
Another item often found on older installations is braided flexible hoses. At one time these were recommended to give protection to the hose, but the overwhelming consensus now is that it’s more important to be able to visually inspect the hose for damage.
It’s worth noting that you must make sure both maintenance schedules and any work carried out on the gas system meets the requirements of the vessel’s country of registration or the country in which it is based. In many cases this means work must be carried out by, or at least checked by, an engineer approved to work with marine gas systems.
Alternatives to gas
The cost of installing a decent gas system in a smaller yacht with relatively low value can be surprisingly high. However, there are a number of viable alternatives to using gas on board for cooking. The most common of these is alcohol cookers – modern types are easy to use and, although the flame is not quite as hot as a gas one, they still come close to rivalling cooking on a gas stove. Other alternatives include paraffin cookers, which have a pressurised tank, or even diesel units, although these options are more expensive than an alcohol stove.
For other maintenance tips, see 15 best boat fitting out tips and How to maintain your boat.