Long Island Marine Surveyor

Telephone 631 589-6154  Fax 631 563-3758

 NFPA USSA  FMANA SNAME USNI ABYC 

Long Island Marine Surveyor 631-589-6154

Fuel systems

Gasoline tanks are make from aluminum, fiberglass, monel or stainless steel.  Aluminum is the preferred material for gasoline tanks, stainless steel and fiberglass are not recommended.  Diesel fuel tanks should be stainless steel or aluminum and both metals are recommended for diesel fuel tanks.  Monel is no longer used because of its expense.   All fuel tanks must be grounded.  The fuel system must be liquid and vapor tight to the hull interior, the metal components of the fuel system and the fuel tank must be grounded.   Fuel tanks must be properly secured.  The fuel tank must show no evidence of leakage.  The vent line from the fuel tank must be USCG approved hose greater than 7/16 inches diameter J1527 hose. 

Fuel fill line to gasoline tank must be in acceptable condition this line is marked with the date of manufacture is J1527 USCG approved and should be anti alcohol hose.   Alcohol a recent additive to gasoline eats away at older type fuel hose.  The fuel fill hose must be in acceptable condition and it must be approved hose.  Cracking often is visible on fuel fill hose at sections where they bend, after a few years of use.  It is not unusual to change this fuel line hose every 5 to seven years, changing this hose should be considered regular maintenance.

Fuel tanks regardless of what material they are made from have a limited lifespan.  This is often a concern on older boats.  The fuel system must be examined for leakage, corrosion, venting, grounding, material construction, fuel fill hose, double clamping, emergency shut down, grounding, stability, condensation, location, ventilation and lifespan.

Fuel from the tank is delivered to the engine via fuel line.  Fuel lines to Carburetors from the engine fuel pump must be metal lines.  Fuel filters and fuel water separators are often installed to clean the fuel and remove water.  Clean fuel is very important to both gasoline and diesel engines but ever more for diesel engines.  Water in the fuel will cause the engine to run poorly and may even damage the engine.  Boat fuel tanks are subject to condensation due to the set up time that most boats are not used.  Changes in temperature and humidity will allow water accumulation inside a boat fuel tank.  Fuel water separators are highly recommended for any fuel system.  Fuel tanks must be filled to capacity in off seasons this will limit the amount of condensation allowed to form inside.

The inside of gasoline and diesel fuel tanks are just as important as the outside.  Gasoline and diesel fuel must be treated when they stored for a few months.  Fuel stabilizers are added to the gasoline and diesel fuel.  These fuel stabilizers can be found in most marine stores and are needed when any vessel in not in use for a prolonged period.  Gasoline when left in a tank for a prolonged amount of time will "varnish".  This is a gummy substance that will clog up you fuel lines, fuel filers.  Diesel fuel is subject to algae growth and must be stabilized like gasoline.   The inside of gasoline and fuel tanks is just as important as the outside.

Occasionally fuel tanks are located in boats where their very location caused problems.  This if often done by boat manufactures for cost, style, or design reasons.  To the boat owner who needs to replace an ageing fuel tank these locations can mean excessive costs when the boat needs to be dismantled to replace the tank.  It is not uncommon to find a fuel tank located where it causes damage to the hull or to itself over time.  Fuel tanks should be located where they absorb as little pounding and vibrations as possible.  They should be well cradled or strapped in place for little movement.  They must be secured with straps, or laminate that is in good condition.

Fuel systems are carefully inspected for any leakage.  A fuel leak can cause and explosion or can get you in big trouble with the USCG.   Insurance Companies insist that fuel systems are in satisfactory before insuring a boat.  Replacement of a fuel tank is often expensive.  Fuel in poor condition will cause operational problems in boats.  Compartments in which fuel tanks are located must be properly vented to the outside air.

(See NFPA, USCG and ABYC directives and recommendations for more specific information).

See Fire Safety for additional information.

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