Warning -hose clamps

[Matt Cawthorne]

Each year when I service the seacocks I give the hoses and clamps a quick check make sure they are in good shape. They have always appeared ok, but recently I decided that it was time to replace the hoses for the cockpit drains. The clamps appeared clean and corrosion free from the outside. When I applied minimal (very minimal) torque to the screw to remove the first clamp the band broke. Between the two hoses three of the clamps failed in the same manner. This is a clear case of oxygen starvation. The back sides of the clamps were badly corroded yet the outside looked fine. The clamps were labeled "aero seal" and "stainless" I did not take the time to see if they had an austinitic grain structure, but I suspect that they did because of the good appearance on the outside. The cockpit used to leak in this area which would aggravate the situation.

Recommendation: REMOVE hose clamps and inspect them once in a while. Especially ones below the water line.

The hoses themselves were weaker than I would have liked to see. I suspect that they were original parts which would make them 17 years old. Even if they appear in good shape I will replace them sooner next time.



mcawthor@bellatlantic.net

[Chris]

Matt -- A recommendation which was made to me by the Marine Surveyor who surveyed my boat prior to purchase was to replace ALL your hose clamps on a rotating schedule. He recommended to replace ALL the clamps and hoses upon the purchase of a used boat which was greater than 6 years old. He further recommended to have all hoses attached with two clamps at each connection. A replacement procedure should then be established where one of the two clamps would be replaced in 3 years (either all the inner or all the outer clamps). The remaining set of clamps should then be replaced, along with the hose, after another 3 years. This systematic approach guaranteed a maximum of 6 years use from any hose or clamp, with at least one clamp 3 years or less on each connection.

Each year when I service the seacocks I give the hoses and clamps a quick check make sure they are in good shape. They have always appeared ok, but recently I decided that it was time to replace the hoses for the cockpit drains. The clamps appeared clean and corrosion free from the outside. When I applied minimal (very minimal) torque to the screw to remove the first clamp the band broke. Between the two hoses three of the clamps failed in the same manner. This is a clear case of oxygen starvation. The back sides of the clamps were badly corroded yet the outside looked fine. The clamps were labeled "aero seal" and "stainless" I did not take the time to see if they had an austinitic grain structure, but I suspect that they did because of the good appearance on the outside. The cockpit used to leak in this area which would aggravate the situation.

Recommendation: REMOVE hose clamps and inspect them once in a while. Especially ones below the water line.

The hoses themselves were weaker than I would have liked to see. I suspect that they were original parts which would make them 17 years old. Even if they appear in good shape I will replace them sooner next time.

[Kurt]

I echo your sentiments regarding periodic inspection and planned replacement of all "below the waterline" hoses and clamps. True USCG approved marine hose is manufactured with the date imprinted every foot or so on the jacket enabling the servicer to determince its age even if the history is unknown. This is the ONLY type of hose to be used below the waterline. All connections should be double clamped using only 100% stainles steel clamps.



kjlgpw@aol.com