It is easy to ignore the fittings that clamp a hose onto an engine or seacock, but jubilee clips are all that stand between you and sinking, says Dag Pike

Take a look into the engine compartment of any yacht and you will see flexible pipes everywhere and hopefully see them fully secured with a jubilee clip or perhaps using a more generic term, worm drive clips, writes Dag Pike.

It can be the same when you look into the bilges where there can be pipework of all sorts linking up the ever increasing complexity of the plumbing systems on board.

Those jubilee clips are a vital part of the safety of your yacht but we tend to take them for granted, until they fail, that is.

Two types of jubilee clip

Left: 316L stainless steel with grooved thread. Right: 304 stainless steel with through-cut thread

‘Why should they fail?’ I hear you ask.

A jubilee clip is made from bright shiny stainless steel and they are there for life, or at least until you need to replace the hose that they are securing.

Surely they are one of the things on a yacht that should not concern you unduly?

Have a think, however, about just how important they are.

They are designed to hold the hose that is connected to a spigot securely.

Seacock failure on a yacht

If a hose comes off a seacock, the source of the leak may be underwater before you find it. Credit: Graham Snook/Yachting Monthly

The consequences if they fail are that you can suddenly have a hole in the hull through which the seawater can pour in.

You may be able to find the seacock in time to be able to turn the water flow off but the chances are that it will be well underwater before you identify the problem and before you find that seacock, always assuming that there is one on the pipe in question.

It is not only on water pipes that you can find jubilee clips being used to secure a hose.

They are frequently used on the flexible sections of fuel pipes that allow the engine to be flexibly mounted, and if the jubilee clip fails there you could well get fuel leaking into the bilges or at least the engine might stop.

Wherever you look on a boat there are jubilee clips performing a vital role, so it is time to take them seriously.

Causes of  jubilee clip failure

There are two main reasons that a jubilee clip may fail.

One is the poor quality of some of the clips that can make them susceptible to corrosion in the salt-laden atmosphere of a boat’s bilges.

The other is that often in the interests of economy, only one clip is used to make a connection when a good quality connection should always have two.

hose connections on a yacht

Regularly inspect hose connections

Let’s look at the quality of the clips that can be found on a yacht.

To be secure and to take away any chance of corrosion, the clips used should be made from marine quality stainless steel which tends to be more expensive than the more mundane stainless steels used for other purposes.

There are so many different grades of stainless steel, each with different characteristics and the corrosion resistance can differ greatly.

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A broad brush method of testing stainless for its corrosion-resistant properties is to use a magnet. If the stainless is non-magnetic then there is a good chance it is marine quality.

If you have a magnetic knife rack at home you can see how stainless steel knives will stick to it.

This is because knife stainless has been formulated for its ability to hold a sharp cutting edge.

The exhaust on a boat

Heavy duty hose clamps are required on the exhaust

Other cheaper stainless steels are also magnetic but the marine grade should not be, so go for non-magnetic clips.

Beware that for domestic purposes, galvanised steel or other metals are sometimes used – a cardinal sin aboard.

There are two main types of jubilee clip; those with the screw threads in the straps cut right through the metal and those with the screw thread cut within the depth of the metal.

The latter are the best because the strap is much stronger with no holes cut in it and the screw is not likely to damage the material of the pipe being connected but of course, they are more expensive.

Engine on a Faurby 460E

Numerous flexible host connections in the engine bay all need careful inspection. Credit: Graham Snook

You can find another type of clip usually used on larger diameter pipes, such as exhaust pipes, where the ends of the strap are terminated in round loops with a metal insert.

Here the screw tightens one left-handed thread and one right-handed to bring the ends closer together.

This type of jubilee clip is more secure and used on critical components.


Dag Pike is one of the UK’s best-known nautical journalists and authors, covering both sailing and motor boating for many years.

When I say critical, all pipes and spigots that connect with the outside water are critical.

If they give way, water comes in so it is common on such connections to use double clips just in case, always assuming that the spigot onto which the pipe connects is long enough to accept double clips.

You can often find shorter spigots on fuel line connections and this reflects their automotive history.

It can be the same with the pipework on an engine, with virtually all yacht engines now derived from automotive units.

In marinising the engines the cheap automotive clips may be replaced with worm drive clips but usually only single clips are used even though a failure can let in seawater.

Jubilee clips look so harmless fitted onto the pipework but a failure has the potential to cause your boat to sink, particularly when left on moorings for a long time.

They should be checked regularly for any signs of decay, including behind them, for which you may need a mirror or a mobile phone.

Hose connection best practice

  1. Good quality 316 stainless steel clips should not need replacing unless they are damaged.
  2. Marine-grade stainless steel will normally be marked 316 on the barrel of the screw.
  3. The grooved type of clip is stronger than the slotted type and kinder to the pipe underneath.
  4. The clip you use should be closely sized for the pipe size so that the barrel sits neatly on the pipe.
  5. If you use too large a clip, it will not apply even pressure and the long tail can be damaged or cause damage.
  6. All critical hose joints such as engine water intakes and circuits, exhausts and below waterline drains should be fitted with double clips.
  7. Jubilee clips should be tightened as much as is possible with a screwdriver but not so tight that they cut into the hose.
  8. If there are no signs of corrosion, leaking or hose deterioration, it is best to leave hose connections intact at the winter overhaul.
  9. The hose with double clips should provide an adequate seal if it is the correct size without having to resort to additional measures.
  10. A wooden bung attached by string to the seacock is often recommended in case of failure but the chances of being able to insert it before the seacock is underwater are small.

Enjoyed reading How a jubilee clip could save your boat?

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