T bolt clamp or double hose clips?

[burgundyben]

When attaching hose to underwater fittings, the general consensus is to double up on hose clips in case of failure (which is likely as hose clips are crap!).

On my previous boat, I fitted the stern gland hose using single T bolt clamps rather than hose clips, see pic.

Clearly a single T bolt has no redundancy in case of failure, but I feel failure a lot less likely.

Thoughts?

I posted the above pic in my previous rebuild thread, I expected a load of comment, but never got any.

 

[omega2]

T clamps every time for "important" sealing, like stern tubes and exhaust elbows and transom outlet. The rest of the hose joints should be checked as you say those worm drive clips are not to be trusted.

 

[Lon nan Gruagach]

Double T clamp, they don't last for ever.

 

[PCUK]

Get them from local hydraulics shop, not 'marine' supplier. Identical stainless steel, same make but 1/4 of the price.

 

[Paul1962]

Get them from local hydraulics shop, not 'marine' supplier. Identical stainless steel, same make but 1/4 of the price.

Alternatively, try Aquafax and make sure all components are stainless steel, some brands are stainless band but with steel bolt

 

[vas]

When attaching hose to underwater fittings, the general consensus is to double up on hose clips in case of failure (which is likely as hose clips are crap!).

On my previous boat, I fitted the stern gland hose using single T bolt clamps rather than hose clips, see pic.

Clearly a single T bolt has no redundancy in case of failure, but I feel failure a lot less likely.

Thoughts?

I posted the above pic in my previous rebuild thread, I expected a load of comment, but never got any.

Ben,

you have enough space there for another two T clamps. MiToS has four on each axle with a v.small gap between 2nd and 3rd.
works fine (touch wood)

cheers

V.

 

[rosssavage]

Definitely band clamps for important stuff!! And use two, rotated 180 deg apart...

 

[omega2]

If four are fitted all at the same time then the chances are all four will "let go" at the same time, they are not fit and forget, CHECK THEM at least once a year.

 

[PCUK]

Alternatively, try Aquafax and make sure all components are stainless steel, some brands are stainless band but with steel bolt

As said, identical and from same manufacturer. Where do you think Aqua Fax get them from?

 

[omega2]

As said, identical and from same manufacturer. Where do you think Aqua Fax get them from?

Ah yes but they do not bear the AQUA bit, and that is the reason! LOL

 

[burgundyben]

As it happens I use Aquafax a lot. Best chandlery on the South Coast.

Noted all comments, double T bolt clamps where possible.

 

[prof pat pending]

Definitely band clamps for important stuff!! And use two, rotated 180 deg apart...

+1 I always use 90 deg, but that might just be habit.

if space is limited, you can get them with 2 bolts side by side on one clamp. These are intended for high pressure applications.

 

[Surfacesub]

When attaching hose to underwater fittings, the general consensus is to double up on hose clips in case of failure (which is likely as hose clips are crap!).

I have seen similar remarks before and often wondered how the failure occurred. e.g. wrong application, materials, torque, design, quality control issue and oxygen depletion! What did the manufacture have to say including warranty, given the disastrous consequences that could unfold in the event of clip failure?

There are nearly always reasons for failure but generally I would have thought a well engineered installation should hold good between obligatory inspections.

If the clips are being used for the wrong application then one could assume that the failure rate of two may be identical which can lead to a false sense of security.

"This brings to mind, the subject of engine bay fire extinguishers when two half size don't deliver quite like one the correct size for the same volume to be protected."

"The RNLI attend more instances involving boats with twin engines failure than with one well maintained."

I have no personal experience involving my last two quotes, but they did come from the horse's mouth so to speak.

 

[David2452]

Personally I am of the opinion that heavy T bolt clamps are inappropriate for many areas on board with the exception of heavy exhaust hose as they can be and are often tightened to a level where damage to the material is caused. I would use a pair of JCS 316 Hi-Torque worm drives (proudly made in Suffolk) with drives at 90 degrees tightened to the recommended torque.

 

[Latestarter1]

Personally I am of the opinion that heavy T bolt clamps are inappropriate for many areas on board with the exception of heavy exhaust hose as they can be and are often tightened to a level where damage to the material is caused. I would use a pair of JCS 316 Hi-Torque worm drives (proudly made in Suffolk) with drives at 90 degrees tightened to the recommended torque.

At last a voice of reason...........

Jubilee and JCS LLoyds as well as ABS approved, finding T bolt clamps even if they are 100% SS may have some Ferritic stainless components.

I regularly use SS T bolt clamps on CAC pipes subject to high pressures but have never seen a certificate of conformity.

Also first mention of the magic word 'torque'............Goes hand in hand with magic words 'mechanical reliability'.

 

[PCUK]

As it happens I use Aquafax a lot. Best chandlery on the South Coast.

Noted all comments, double T bolt clamps where possible.

Nothing wrong with Aquafax Ben, but if you can get the identical product through an industry supplier, then worth the huge saving. Same applies to most engineering type equipment.

 

[omega2]

Some of us know where to look!