[GordMay]

Double Clamping Hoses - A (Controversial) Caution:

I posted the following opinion some years ago (don’t recall where), and wonder if anyone has had any luck in locating good hose barbs (& barbed fittings) that have longer stems - long enough to accept the recommended TWO hose clamps?

There has been a lot of discussion concerning the "Good Marine Practice" of
double clamping hoses. Many Marine Surveyors in their "Recommendations" will often (almost always) state, "Double clamp all below water line hoses."

Modern (high quality) hose clamps are a passivated stainless steel strap with stainless steel worm screws (unless one buys the clamps at auto supply or home improvement
stores). Unfortunately, modern hose barbs are too short to accommodate two clamps.

At an ABYC seminar several years ago, Pat Kearns of ABYC said that she could
find no reference to double clamping of hoses, except fuel and exhaust hose.
None of the other thirty-five marine professionals present could cite a reference to double clamping water hoses except those in the CFR (Code of Federal Regulations) which relate to other than recreational vessels.

I surveyed a boat last month that came close to sinking because the owner,
based on the advice of a previous surveyor to double clamp, added an additional clamp. That second clamp was just past the end of the barb and actually pulled the
hose partially off. I was able to wiggle the hose and pull it off the barb
(with the boat high and dry at the time).

Therefore, be extremely careful about double clamping. Only do it when you
are sure that the hose barb is of sufficient length to accept the clamp. I often install the second clamp loosely on the hose, so that it’s immediately available should the prime clamp fail. I also tie (light string) a soft wooden cone plug to each through-hull fitting.

BTW: If you have to remove a hose, it occasionally works to relocate the clamp to
the end of the barb and you may be able to use it as a device to remove the
hose. That doesn't work on an old salted up bronze barb, but often works on plastic fittings.

I look forward to any comment & opinion.
Agree? - Disagree? - Why?

Gord