Constant-torque hose clamps

[DLETF]

A marine surveyor has recommended that the raw water intake hose and clamps be replaced. He has recommended constant-torque SS hose clamps. The current clamps are the worm-gear SS type but not constant-torque. I am interested in TF members opinions about the type of hose clamp issue.
Thanks.

[Comodave]

I like the AWAB clamps. They are more expensive but are all S/S and don’t cut into the rubber hose.

[psneeld]

saw a caterpillar engine straight from the factory charcoal itself because one of the "premier" hose clamps break on a coolant line 60 miles east of Jacksonville Beach.

sometimes theory is great, but some of the better engineered products are still far from perfect and the leaser ones are still good enough most of the time.

so I call it a toss up.....its your money.

[O C Diver]

Most raw water intake hoses (before the pump) have wire in the hose or similar to keep them from crushing under vacuum. I uses the heavier duty worm clamps, two per end with worms 180 degrees apart. I think heavier duty is more important when trying to seal the wire hose. Nothing wrong with constant torque, just don't see the need on extremely low pressure or vacuum hoses.

Ted

[LarryM]

Originally Posted by DLETF

A marine surveyor has recommended that the raw water intake hose and clamps be replaced. He has recommended constant-torque SS hose clamps. The current clamps are the worm-gear SS type but not constant-torque. I am interested in TF members opinions about the type of hose clamp issue.
Thanks.

I recently replaced every hose and clamp on my boat. I used Breeze CT XXX L SS 5/8" 304 SS Band clamps on all engine water and turbo hoses. I used Shields T-Bolt 316 SS clamps (double-clamped) on the exhaust hoses. Finally, I used ABA SS Rolled Edge clamps everywhere else, on the smaller fuel lines, coolant recovery hoses, sanitation and water system, and double-clamped where indicated. Overkill, perhaps, but I am more confident and that's what's important to me.

The Breeze CT clamps were OE on my Cummins 6BTA's, so that's what I replaced them with. Their spring mechanism allows them to increase or decrease their diameter with changes in temperature. They have an inner liner that protects hoses from damage and helps maintain a constant sealing pressure. Finally, they have a "Torque Check" visual indicator of tightness. They are not cheap, but they are IMO the best you can buy.



I think I should have them all paid for by sometime next year

[caltexflanc]

Larry summed up the uses of various clamp types nicely. On the "hot" side of an engine you use them for exactly the reason Larry lists. Temps don't change radically on a raw water intake. I could see using T bolt clamps maybe for security's sake. But a good set of AWABs would be fine with me too.

Psneeld, what exactly was the "premier" clamp you refer to, and how long had it been in place and/or gone uninspected?

[psneeld]

One of their tbolt spring Cat clamps.... the mech called them constant torque.

The engine was installed at the Sea Ray factory in Canaveral. It was test run, readied for water delivery as it was a 54 footer and the failure was whatever the time was to get to the ocean and then at 20 something knots off Jacksonville.

My guess the engine had around 10 to 15 hours at that point

[Lepke]

There is no end to a more expensive solution for anything connected to yachts. If it makes you feel better, use the constant torque clamps.
I've been using ss worm drive hose clamps since at least the early 1960s w/o a failure. Mostly on commercial boats and ships that got heavy use.

[Bigsfish]

AWAB clamp are what I use when I change the existing clamps. A boat builder friend turned me on to them because they won’t cut the hose because the worm gear doesn’t go thru the band. I’ve been happy with them.

[Northern Spy]

Originally Posted by DLETF

A marine surveyor has recommended that the raw water intake hose and clamps be replaced. He has recommended constant-torque SS hose clamps. The current clamps are the worm-gear SS type but not constant-torque. I am interested in TF members opinions about the type of hose clamp issue.
Thanks.

Personally, I would ask him why. I would want to know his opinion.

Constant torque clamps in my experience are used for two reasons: large temperature swings or hose material that creeps (PTFE lined) over time.

I'd argue that the spring composed of Belleville washers are more susceptible to SCC because they are stressed, alternatively they are not 316SS material, and subject to corrosion. Either way, they are likely to require periodic replacement.

I, like many others, prefer the DIN style clamps with the embosed, instead of perforated band. If you get DIN clamps be sure they are W5 (316) material.

[tiltrider1]

If the surveyor casually recommended these clamps as a good idea, great looks like a superior product. If he is putting this in a report I would be upset unless they were specified by the engine manufacture.

Worm style hose clamps do create a flat spot on hoses which in turn becomes a premature failure point. However I find hoses crack before they fail and I have always replaced hoses at the first sign of cracking. So while constant torque clamps are technically superior, functionally I see no gain.

[dhmeissner]

Excuse my ignorance please. AWAB is a brand name right? So want is a “constant-torque clamp”?

[Ski in NC]

Constant torque has a stack of belleville springs under the screw head. When you tighten the screw, the springs compress. Then as hose extrudes over time, the clamp still has a good bite. Well worth it on engines where hoses hold considerable pressure and have wide swings in temp.

Seen several cases where someone replaced the hoses on their engine then a week later a hose blew off. Were using standard clamps, not constant torque.

If you replace hoses, a week later go down and snug EVERY clamp. Even if using constant torque.

[FF]

"A marine surveyor has recommended that the raw water intake hose and clamps be replaced. He has recommended constant-torque SS hose clamps."

Surveyors need to justify their expense.

If this is all he could find wrong with the boat , its a great boat OR you still need a real survey.

[Bigsfish]

Not sure if I follow the logic here. Everyone agrees that constant torque hose clamps are best. So my question is how much more money will it cost for the average boater to replace his existing clamps with the improved once? Are we talking thousands of dollars? Hundreds of dollars? Maybe less? A few beers? So now we are putting a value of your life and those with you. Do you buy health insurance?

SMH

[Northern Spy]

Originally Posted by Bigsfish

Not sure if I follow the logic here. Everyone agrees that constant torque hose clamps are best. So my question is how much more money will it cost for the average boater to replace his existing clamps with the improved once? Are we talking thousands of dollars? Hundreds of dollars? Maybe less? A few beers? So now we are putting a value of your life and those with you. Do you buy health insurance?

SMH

They aren't the best. They suit a specific purpose.

I would like to understand why the surveyor thinks they add benefit to the suction side hose of a water pump.

"striving to better, oft we mar what's well"

[AusCan]

Constant torque hose clamps may be better in some applications but not all. It would cost hundreds of dollars to change out all clamps and only a few of them would be better off. I’d save my money and just check whatever clamps you have on a regular basis.

[psneeld]

A common misconception on many projects and products discussed here.

[Bigsfish]

So I misinterpreted the fact that these clamps aren’t best! What is their drawback other than cost?

[psneeld]

application....for the few instances where constant pressure on the hose and barb is necessary through multiple thermal cycles to maintain no leak...they are best.

for all other applications they are way overkill as you can see in other applications like on cars where el cheapo spring clamps are used. Even on expensive vehicles and last for decades.

Heck, I have seen zip ties used in applications holding gasoline lines.

Some boating thinking is run by ex NASA guys or worry warts based on the amount of overkill spewed these days.