I only use one clamp 80% of the time or more.
Umm good luck with that..
I don't think you really need more than one for most situations.
I would agree with that statement, if, it is an item or hose that CAN NOT sink your boat. Appropriate use of single clamps might be the fresh water system but not seacocks or thru-hulls.
If the hose is under pressure (e.g. Exhaust hose) I would prefer two.
Actually a seacock a foot below the surface is under as much pressure as an exhaust hose. Exhaust systems are designed for minimal to no back pressure and all you're really doing is moving water through it.
As Maine points out, most barbs are not large enough for two, so adding a second would be dangerous (it would have the effect of pulling the hose off the barb).
Actually I did not say most barbs are not long enough. I said some manufacturers still make products without enough room. Most all marine rated bronze or Marelon barbs are indeed long enough. It is when DIY's decide to visit Home DEpot and use brass barbs that they often come up short. Barbs should always be measured against the two clamps intended for use.
These are marine rated bronze barbs and are plenty long enough.
This is just barely long enough.
I think regular inspection and replacement is far more important that what type of clamp you use. As someone above implied with the coast guard boat, inexpensive stainless clamps are fine (as long as they really are stainless), just replace them all every few years.
I will just have to agree to disagree on this point. Having worked on and around boats for years and years I can count on zero fingers the number of AWAB or T-band clamps I've replaced. Actually, I did see one giant T-Band clamp fail on a 12 cylinder Caterpillar on a 100 foot motor yachts turbo intake. This was due to thread galling though and not a failure of the clamp. The installer over tightened galled threads..
On the other hand I have replaced literally hundreds of failed stainless Ideal clamps. I used to have a bucket of them that I showed to friends who insisted on buying cheap Ideal clamps. I used to call them "slip & strip clamps"..
The poor quality of the Ideal clamp is perhaps the sole reason the ABYC USCG and the CFR specify double clamps on flexible below water hoses.
And as the USCG states: "All seawater flex hoses shall have double corrosion resistant clamps."
Anatomy of a failure that I have seen all to often.Didn't take me long to find a failed perforated clamp in the barn. All I did was dig around a couple boxes of old parts..