Part 2- Fixed fuel systems and permanently installed engines

Introduction to the subject matter covered by the checks in Part 2

The watertight nature of boats means that they also act as good containers for leaks or overflows of flammable liquids and vapours.

Stored fuels such as diesel or petrol in confined and undrained spaces carry the risk of providing fuel for a fire or explosion. Part 2 covers the need to keep fuel away from sources of ignition for as long
as possible.

It also covers why the fuel filling and fuel supply arrangements must not allow leaks to accumulate inside the confines of your boat. Thus, all fuel system components must be in good condition. They must also be fire resistant, suitable for the fuel being used and kept away or shielded from sources of heat.

To avoid pollution, spilt fuel oils are normally prevented from being discharged into the waterway and the detail of prevention is in Part 9.

However, the overriding need to minimise the risk of fires, spread of fire and explosions, means that small amounts of overflowing fuel are better directed overboard than allowed to flow into the craft interior.

These requirements and checks apply to all boats with inboard engines and to other fixed fuel systems supplying liquid-fuelled appliances such as diesel heaters. Further requirements relating to appliances and their installation and maintenance are in Part 8.

If you carry spare fuel in portable containers, the requirements related to the safe type and location of spare fuel containers is covered in Part 5.

The BSS requirements associated with Fixed fuel systems and permanently installed engines:

  • 1 All permanently installed fuel systems and fixed engines must be designed, installed and maintained in a way that minimises the risks of explosion, or of fire starting or spreading.
  • 2 Fuel filling arrangements must prevent any overflow from entering the interior of the vessel.
  • 3 All fuel filling points must clearly identify the fuel in use.
  • 4 Marking must be provided to identify the location of fuel system emergency shut-off devices, or their means of operation, which are not in open view.
  • 5 All permanently installed fuel systems must be designed, installed and maintained to ensure fuel-tight integrity.
  • 6 All permanently installed fuel tanks and fuel system connections must be accessible for inspection.
  • 7 The pressure systems of steam-powered installations must have a current inspection certificate issued by a recognised competent person.


Notes on the qualities of fuels that have a bearing on the nature of the Requirements and the Examination Checking Procedures

Petrol is very volatile and quickly produces highly flammable vapours. Small spills of petrol create relatively large amounts of vapour.

The risks are also there when it is being transferred and especially when a tank is being filled and the vapour in the 'empty' tank is displaced by the liquid fuel.

Even if the concentration of vapour is too rich to burn immediately, it will dilute to flammable or explosive levels, even though when given enough ventilation, it may dissipate to a safe level eventually.

Petrol vapour is three to four times heavier than air. It will sink to the lowest level of its surroundings, accumulating at low level in places such as unventilated lockers and bilges or in enclosed spaces such as the
cabins and cockpits of boats.


Diesel, like petrol, as a liquid does not burn, but when it is heated, the vapour given off is combustible and will burn strongly.

Diesel reaches this flash point, at around 56°C and this can be even lower in winter due to the anti-waxing additives. Diesel can be raised to flash point temperature by contact with flames, frictional sparks, electric sparks, and small fires as well as other heat sources.

Diesel fuel will ignite readily; thus materials soaked with diesel i.e. wicking, will help the spread of a fire. Once alight, diesel burns with great heat and strength.

The proposals

The revised version of the ECPs can be read from a pdf format file by clicking the link on the image on the right below.

The orginal version of the Checking procedures can be read by clicking on the link on the left-hand image. This will launch the chapter of the BSS Guide that also contains all the relevant guidance and descriptions which may offer a more whole perspective.

Pt2 300x200

ECP Cover 300x200

Click on this image to see original ECPs and notes  Click on this image to see Proposed revisions