The Church of Double Clipping

[Stemar]

Second so I do not forget to turn the water on next time I use the engine

If you have key ignition, the trick is to hang the key on the closed seacock.

 

[Bouba]

If you have key ignition, the trick is to hang the key on the closed seacock.

I have an A4 sheet of paper with big letters saying the seacocks are closed which I tape to the dashboard

 

[Roberto]

I have an A4 sheet of paper with big letters saying the seacocks are closed which I tape to the dashboard

Double sided adhesive and on the other side big letters saying seacocks are open so one does not forget to close them

 

[westernman]

You do it all the time in decision making. There is NO evidence that adding an extra clip stops your boat from sinking. This is a non issue.

I believe RCD mandates double clipping of hoses.

In which case insurance is not going to pay out if your boat sinks if a single clipped hose could have been conceived to have participated in some way to the incident. Or just used as an example of lack of maintenance.

 

[Fire99]

It's 'your dime, your dollar' at the end of the day but for me a lot of safety / maintenance things on the boat are for my own piece of mind rather than a likely failure. Knowing I've 'double clipped' below waterline fittings with good quality clips as another thing to have peace about. Considering how relatively cheap the clips are and usually how easy they are to fit, I can't think of a reason not to. Obviously if the clip is going to cause a bigger problem than I'm solving (clip is compressing the hose beyond the tail) then that's a different story. But generally it's an easy job for a little more boat confidence.

 

[Tranona]

I believe RCD mandates double clipping of hoses.
In which case insurance is not going to pay out if your boat sinks if a single clipped hose was involved.

Do you have a reference for that in the RCD - never seen it. Insurers do not make compliance with RCD a condition anyway,

Rather a moot point as I think it is now well established that firstly sinkings (and therefore claims) following clip failure are rare to non existent and that double clipping does not change this.

This is clearly for some an emotive issue to the point that they are not "at peace" unless all clips are backed up with a second one (of the same type (so just as likely or not to fail).

Technical advice, logical reasoning and lived experience clearly don't count.

 

[westernman]

Do you have a reference for that in the RCD - never seen it. Insurers do not make compliance with RCD a condition anyway,

Rather a moot point as I think it is now well established that firstly sinkings (and therefore claims) following clip failure are rare to non existent and that double clipping does not change this.

This is clearly for some an emotive issue to the point that they are not "at peace" unless all clips are backed up with a second one (of the same type (so just as likely or not to fail).

Technical advice, logical reasoning and lived experience clearly don't count.

I have just checked the RCD and MCA Blue book and indeed I can find no reference to double clamping.

When I bought my boat it was mentioned in the sales literature that all hoses were double clamped according to those requirements. May be it is in some subsumed documented practice?

If it is somehow standard documented practice to double clamp, and your boat sank because a hose came loose, then if it is "standard" practice, it gives insurance companies enough wiggle room to drive a bus through.

I do agree, that double clamping brings no advantage.

 

[Tranona]

It is a myth perpetuated by it being on the standard surveyors template report form.

The origins are in the mists of time when hoses and clips replaced solid pipework (usually copper with screwed gland fittings) and of course resistance to new fangled ideas (hoses are going to chafe through, clips corrode or break and so on) - forgetting the number of failures of solid pipework!. The fears were not totally without foundation as flaming explained but quality and design of both clips and hoses quickly improved and the potential problems never happened.

The fear is sinking, but that is a very rare event anyway, and rarely (if ever) caused by hoses coming off. Quite remarkable really given how many millions of holes there are in the bottoms of boats that are protected only by hoses clamped to spigots.

Very difficult to shift a "belief" when it becomes so well embedded, confirmed by every surveyor's report and clips are so cheap.

 

[ean_p]

Thanks.

If anyone has any specific questions let me know and I’ll try to answer.
Equally if anyone finds themselves in Suffolk and wants a factory tour just PM me.

Hi Flaming and many thanks for some interesting info.
I've a couple of questions if you'd be so good please.
On the German clips is there a specific reason for the embossing being offset and as such should the clip be orientated in any specific way relative to either the fluid flow and or the barbing on the spigot ( assuming there is barbing)?
You mentioned that the Hi-Torque bands are suitable for use on spirally reinforced hose as most other bands tend to fail as the reinforcing interferes with the clamping process. Does the Hi Torque succeed simply because the increased pressure 'distorts' the reinforcing material such that it reduces to the same as the hose wall material. and would it still succeed in a hose with a metallic spiral? And how do band clips such as Hi -Torque compare to what is the usually recommended clamp type which is the 'twin wire' type? I know such hoses are really suction type hoses but their use is becoming more and more ubiquitous. Personally I hate them as they always fail either by the spiral 'cutting through the wall or the fluid being able to 'travel' down the spiral because the wall has failed somewhere internally. Do you have any 'insider' info re the 'twin wire' type clips please?
Finally a bit of an observation. I understand that the BS test requires a leak free period at up to 200psi . In your video that appears to be on a smooth walled spigot without any barbs. Is this so? In a real world scenario I couldn't envisage anyone really maintaining that level of energy simply by the compressive force of a clamp in that way. Further it has always been my understanding that the 'seal' on a hose on a spigot is actually between the barb lip and the hose internal wall which is or should be sufficiently pliable in order to 'settle' around the lip. The hose clamp then has a different function and that is to exert sufficient pressure so that the hose does indeed settle around that lip and also that the diameter of the inner wall of the hose is such that its 'smaller' than the barb and hence the hose cannot slide off the spigot. If these assumptions are right then the 'ultimate' clamping force is almost irrelevant in day to day use and a moderate pressure applied to the hose just in front of the barb will suffice for almost all situations (thinking of the spiral hose failing here) would you agree?

 

[pandos]

Because if it's done that way.., then no matter where the fixture, there will always be at least one clip that is impossible to remove without coming away bleeding and cursing.., which is, after all, why we own boats.

When this happens it is important to remember that you poo pooed at the idea of buying little coloured protective plastic condoms for the ends of the clips...

 

[flaming]

Hi Flaming and many thanks for some interesting info.
I've a couple of questions if you'd be so good please.
On the German clips is there a specific reason for the embossing being offset and as such should the clip be orientated in any specific way relative to either the fluid flow and or the barbing on the spigot ( assuming there is barbing)?

The stated reason to offset is that the Torque input in doing up the screw pushes the screw offset in the housing, so might as well allow for that and have the embossing off centre. Having never tried to make a German style clip, there might be something in that, but it's not an issue we've ever seen in a British style clip.

You mentioned that the Hi-Torque bands are suitable for use on spirally reinforced hose as most other bands tend to fail as the reinforcing interferes with the clamping process. Does the Hi Torque succeed simply because the increased pressure 'distorts' the reinforcing material such that it reduces to the same as the hose wall material. and would it still succeed in a hose with a metallic spiral? And how do band clips such as Hi -Torque compare to what is the usually recommended clamp type which is the 'twin wire' type? I know such hoses are really suction type hoses but their use is becoming more and more ubiquitous. Personally I hate them as they always fail either by the spiral 'cutting through the wall or the fluid being able to 'travel' down the spiral because the wall has failed somewhere internally. Do you have any 'insider' info re the 'twin wire' type clips please?

The reason Hi-Torque works on some of those hoses is simply that they are able to exert significantly more pressure than a standard clip. And mostly we're talking about hoses that are essentially smooth inside and out but with reinforcement either in the form of wire or other material woven into the rubber. This is most often, in marine applications, used in exhaust hoses. And it's really more about protecting the hose from abrasion than it is about sealing higher pressures, but it does create a challenge for the clip as the hose is then significantly stiffer.

The Spiral hoses are a different matter, and here we're really talking about very specialist applications. To clamp on those you either need to be able to match the clamp to the spirals, or to compress the spirals. Exactly what the best solution will be depends on the hose and how compressible the spiral is. My view is that if the spiral is relatively soft you're best off ignoring it and clamping as hard as you can with a Hi-Torque, but if it's very rigid then you're probably best off going with either a twin wire clip or a spiral clip. The twin wire clips are an interesting beast, they can test up fairly well when used with pretty rigid spiral hose, but I have my doubts about what their long term effect on the hose in terms of abrasion etc would be. I'd certainly be inspecting frequently if they were on an application that had significant vibration.

This is the alternative type. We keep getting asked for them but haven't found the time to develop one yet, and in the limited testing we have done, have not found any significant advantage over just crushing the whole thing with a Hi-Torque, as the offset design seems to lose a lot of the clamping force.
Spiral Hose Clamp - Schwer Fittings

But I also think that if a Hi-Torque can't do the job there you really should be looking at specialist hydraulic couplings.

Finally a bit of an observation. I understand that the BS test requires a leak free period at up to 200psi . In your video that appears to be on a smooth walled spigot without any barbs. Is this so? In a real world scenario I couldn't envisage anyone really maintaining that level of energy simply by the compressive force of a clamp in that way. Further it has always been my understanding that the 'seal' on a hose on a spigot is actually between the barb lip and the hose internal wall which is or should be sufficiently pliable in order to 'settle' around the lip. The hose clamp then has a different function and that is to exert sufficient pressure so that the hose does indeed settle around that lip and also that the diameter of the inner wall of the hose is such that its 'smaller' than the barb and hence the hose cannot slide off the spigot. If these assumptions are right then the 'ultimate' clamping force is almost irrelevant in day to day use and a moderate pressure applied to the hose just in front of the barb will suffice for almost all situations (thinking of the spiral hose failing here) would you agree?

As you point out the barb can have a fairly significant impact on the actual seal. But then so does the design and material of the hose.... The only way to get a repeatable test to see if the clip is any good is to remove those variations. Which is why the test is as it is.

As to the interaction of spiggot and hose.... The short answer is "it's complicated". The interaction depends on the size of the barb, the stiffness of the hose and the pressure differential on either size of the spigot.
For example, if you consider the extremes. One extreme is that the barb is fairly small, the hose soft and there is little pressure differential as the seacock is open and fluid is flowing through. In this case there is a good seal between hose and barb, and little pressure from the fluid to pass the barb and approach the part of the hose actually clipped to the spigot.

The other extreme is a large barb, a stiff hose and high pressure on the hose side, with the spigot valve closed. In this case, only the stiffness of the hose is holding it to the barb, so it does not take a huge amount of pressure to force fluid past that and into the gap behind the barb, which with a stiff hose is probably a void. In this case you are then relying entirely on the clamping force of the clip to hold the pressure back. And with the hose clip also having to pull the stiff hose down from the barb to the clamping face, you've also made its job tougher.

This is why barbs are generally fairly moderate. And in any case you don't really find what I'd call barbs on most through hulls. Just ribs. Really speaking you are very much relying on the clamping force of the clip.

 

[PetiteFleur]

Many years ago with my first boat, I fitted new hoses to the seacock for the inlet to the loo. I asked the boatyard to check this when launched and a good job I did as there was a pin leak adjacent to the hose clip, the yard refitted the clip after cutting off a short length. Can't remember but I suspect it only had a single clip.
I always use JCS Higrip clips nowadays.

 

[chriscallender]

It is a myth perpetuated by it being on the standard surveyors template report form.

The origins are in the mists of time when hoses and clips replaced solid pipework (usually copper with screwed gland fittings) and of course resistance to new fangled ideas (hoses are going to chafe through, clips corrode or break and so on) - forgetting the number of failures of solid pipework!. The fears were not totally without foundation as flaming explained but quality and design of both clips and hoses quickly improved and the potential problems never happened.

The fear is sinking, but that is a very rare event anyway, and rarely (if ever) caused by hoses coming off. Quite remarkable really given how many millions of holes there are in the bottoms of boats that are protected only by hoses clamped to spigots.

Very difficult to shift a "belief" when it becomes so well embedded, confirmed by every surveyor's report and clips are so cheap.

I'm glad there's someone else that thinks like me... my experience is the things that are likely to cause problems in a boat are the things that never occurred to you to check until they broke, not stuff like this. I'd rather spend the time that it takes to fit a second clip looking very carefully at the the cap shround tangs and chainplates for instance. There aren't usually backups for those, they are good candidates for corrosion and I'll bet they fail much more often than hoses jump off skin fittings. So I don't see any reason to double clip either, I did replace some hose and single clips this winter that looked like they were getting a bit past their prime.

 

[DangerousPirate]

It's just boat tradition. Every boat I owned so far came double clipped, and I can't remember a case of any boat that wasn't double clipped, at least as far as I could tell when I saw it.

 

[MikeBz]

I’m pleased to see that the clips I’ve bought from 2 local chandleries recently (Titchmarsh marina and Foxs) are JCS Hi-Grip.

 

[Alicatt]

Last night I was catching up on the Youtube channel "B is for Build" and his modifying a Riva 43 Tropicana. He bought the boat just before Covid and he took his first trip out on it along the Columbia River to the ocean where one of the Detroit diesels decided it did not want to play any more. So he got the boat hauled out, engine out and it was unsalvageable, then he got diagnosed with cancer and abandoned the project for a couple of years and came back to it after getting into remission. He fitted a pair of LS V8 petrol engines to the boat and used it over the summer season.
The boat was left in the water over the winter when he got a call to say that his boat had sunk during a freezing storm. He got the boat raised and found the leaks, one engine he had single clipped the raw water hose to the heat exchanger and the hose had blown off, the other leak was the raw water strainer on the other engine the housing had cracked those hoses on the strainer were double clipped.

He is quite the novice with boats but he is a vehicle builder and engine tuner, so not a novice with mechanicals, they stated that over 20 boats in the area sunk during that storm.

Edit: He used nut and bolt hose clamps

 

[flaming]

Frozen hoses is a bit of a different issue, and as he points out, his 1st clamp passing the test on the other engine simply moved his failure further into the boat.

What he really needed to have done was to drain the system, fill with antifreeze and close the seacocks. Oh, and run a heater. Which is exactly what I do in the significantly less extreme Hamble climate with the boat safely on a cradle!