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I recently received a query from a reader regarding a requirement for double hose clamps on all of the hoses in his boat’s fuel system. It seems that during a recent survey for insurance the surveyor recommended that double clamps be added “based on ABYC Standards”. The reader is a little confused because the boat hasn’t been modified since new 6 years ago. So, what’s the real deal here?
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This one is easy to answer. The ABYC does NOT require that double hose clamps be used anywhere in your fuel system other than for the fuel fill hose. Double clamping of the fuel fill hose is a USCG requirement under Title 33 of the Code of Federal Regulations for recreational boats. In this case the ABYC Standards (H-24 and H-33 for gasoline and diesel systems respectively) mirror the Coast Guard requirements.
As a matter of fact, in many cases double clamping can do more harm than good. In the photo above, the double clamping at the fitting on the left is really causing a problem. the second clamp (farthest away from the fitting) is actually only clamping on the hose. The nipple on the fitting is not long enough to reach under the clamp. So, when tightening the clamp it actually starts to create a pulling effect on the hose as it tries to pull the hose off the fitting. Also, the end of the nipple is cutting into the inside of the hose also causing damage.
Further, in the photo above the clamps used are actually the wrong size. Notice the extended “tails” of clamp band beyond the screw mechanism. Sloppy workmanship. Beyond that, the outboard engine primer bulb really has no place located in the compartment shown as it is below deck. I’m not a fan of having primer bulbs located in enclosed areas on boats. Out on deck is fine, but due to their propensity for leaking I like to see them in an area where plenty of natural ventilation is happening, not buried in a closed space.
So, double clamps for the fuel system? Fuel fill hoses yes, all other hoses in the system, not required and sometimes can do more harm than good.