Marine fuel hose is built and certified to a different standard from automotive fuel hose because a fuel leak on a boat collects in the bilge rather than draining away. Ours is manufactured to ISO 7840 A1 specification with a nitrile rubber inner tube, polyester braid reinforcement and a nitrile blend cover. ISO 7840 A1 is the fire-resistant grade required for permanently installed fuel lines on recreational craft.

Both are ISO 7840 fuel hoses, but A1 has a much lower permeation rate and is fire tested, so it is the grade specified for fuel feed and return lines in engine spaces. A2 is a lower-permeation grade used where fire resistance is not required, such as some fill and vent runs. Our hose is A1 spec, which means it is suitable for the more demanding positions as well as the easier ones.

Internal diameters from 5mm up to 51mm, cut to order from 1 metre up to a 20 metre full coil. Sizes of 25mm and above include an additional wire helix in the wall, which stops the larger bores collapsing or kinking on tight routing - useful on fill and vent runs where the hose has to turn corners inside a locker.

No, and it is worth being blunt about this. Automotive fuel hose is not fire tested and typically permeates far more fuel vapour, which on a boat accumulates in an enclosed bilge rather than dispersing. Insurers and surveyors will pick this up, and it is a genuine safety issue. Use ISO 7840 hose for any fuel line on a vessel.

Yes - the nitrile inner tube is formulated for modern fuels including ethanol blends, as well as diesel and oils. Ethanol is particularly hard on older hose, so if you are working on a boat that still has its original fuel lines, replacing them is worthwhile even if they look sound from outside. Ethanol damage happens from the inside out.

Use two stainless steel hose clips at every connection, which is what the standard expects for fuel lines below the waterline or in an engine space. Use 316 stainless rather than plated clips, support the hose so it cannot chafe against a bulkhead or engine mount, and keep it clear of the exhaust. Renew the clips whenever you renew the hose.