This past week I was tasked with replacing the backing blocks on two intake seacocks in a sailboat engine space. In the process I discovered that not only were the old plywood backing blocks rotten and leaking but that one of the intake hoses had only one hose clamp on each end on top of which the one pictured here was broken!
On the second seacock one end of the hose was again clamped with just a single hose clamp, the sea strainer end being correctly connected with two clamps.
Neither hose was of a very large diameter and both hoses were melded well enough onto the tail piece I had a hard time removing them but that aside the potential was still there for a flooding situation should the hose come loose because the clamp broke and fell off.
Besides being an ABYC (American Boat and Yacht Council) and thus an insurance industry regulation two hose clamps on all hoses below the waterline is just prudent seamanship!
As for hose clamps, they are not all alike! Hose clamps are made of different grades of metal including Stainless Steel, but not all hose clamps are “all Stainless” and those that are will be of varying grades of Stainless.
Hose clamps from Ideal, like those sold at autopart stores and by West Marine that sell for around $2.00 each only contain all stainless parts if labeled “all ss” otherwise the band may be stainless but the clamp and screw of mild steel.
Even those labeled “all ss” are not the same most are only type 300 grade stainless, one of the lowest grades of stainless steel. Most boat fasteners are type 304 or 308 stainless, your average rigging wire is type 308 stainless, all better grades of stainless, though still not the best grade for use on hose clamps.
For just a little bit less than double the cost of type 300 hose clamps you can find in West Marine and other chandlers type 316 grade stainless hose clamps, usually made by Awia. Yes they cost more but will last more than twice as long, especially in highly corrosive applications like the bilge and engine spaces. They are well worth the couple extra dollars!
In either case doubling your hose clamps on hoses below the waterline is cheap insurance. Inspecting them periodically is also well worth your time!