Weigh It, Fit It, Trust It: A Lifejacket Service Habit for UK Boats

Most lifejackets do not fail because the sea is unusually angry. They fail because nobody looked at them since the last time somebody said they should. An automatic inflatable is a lovely bit of kit: pull the toggle, or let the water do it, and a folded jacket becomes a floating collar. But it is also a small mechanical system with a gas cylinder, a firing head, a water sensor and a bladder. Treat it like a piece of safety equipment, not a cushion with straps.

Safety kit is a verb, not a locker item

The UK season has a way of arriving before the boat is ready. One minute you are sorting antifreeze and hatch seals; the next you are shivering on a pontoon in a force four, wondering why the lifejacket feels stiff and slightly sad. A pre-season MOT in the kitchen, with good light and a cup of tea, is worth more than a panicked rummage in the cockpit locker in July.

The principle is simple: weigh it, inspect it, fit it, and know when to hand it over. If you cannot remember the last time the cylinder was checked, that is your answer.

The annual weigh-in

Start with the cylinder. Every gas cylinder has a gross weight stamped on it. Weigh it on kitchen scales and compare. If it has lost a noticeable amount of weight, suspect a leak or a slow loss and get it checked or replaced. Look for corrosion, deep dents, damaged threads and a chewed O-ring. A cylinder that looks like it has been used as a shackle key is not inspiring confidence.

While the cylinder is out, check the firing head. The indicator should be in the correct position for that model, the body should be free of cracks, and the manual toggle should be reachable and not snagged. If the jacket has fired, even accidentally in a locker, it needs a proper rearm, not a hopeful refold.

Bobbins, cartridges and the right rearming kit

Automatic lifejackets use either a water-sensitive bobbin or a hydrostatic firing head, depending on the model. They are not interchangeable, and a cheap generic kit is a false economy. Buy the rearming kit specified for your jacket, with the correct cylinder, sensor, O-ring and clips. Keep the old parts? No, bin them responsibly and note the date.

If you have fired the jacket for practice, follow the maker's instructions for drying and repacking. Do not stuff a damp bladder back into its cover and call it done. Mildew and salt do not improve anything.

Fit is half the battle

A lifejacket that is too loose can ride up around your ears in the water. A crotch strap is not a fashion statement; it keeps the jacket down where it can do its job. Check that it is fitted, adjusted and not frayed. Try the jacket on over the clothing you actually wear: a thin summer smock is not the same as a winter jacket and oilies. You want it snug but not restrictive, with the zip and buckles done up properly.

If you sail with crew, get them to try theirs on too. A lifejacket that only fits the person who bought it is a locker ornament.

Bladder, foam and slow leaks

Inflate the jacket orally, leave it for a few hours, and see if it holds. A bladder that goes soft is telling you something. Check seams, valves and the oral inflation tube. Foam panels can degrade or go crunchy with age; if the foam is cracked or compressed, the jacket is past its best. Also check reflective tape, whistle and light. A light with a flat battery is just a small plastic reminder of better intentions.

DIY or service station?

DIY is fine for visual checks, weighing, oral inflation tests and rearming to the maker's instructions. Send the jacket to an MCA-approved service station if it has been fired, has a damaged firing head, fails an inflation test, is beyond the maker's service interval, or you simply do not trust your own diagnosis. In the UK, many chandlers and lifejacket specialists offer postal servicing. It is not glamorous money, but it is cheaper than replacing a whole jacket, and much cheaper than learning the hard way.

Spares worth carrying in 2026

For the 2026 season, keep a small lifejacket spares bag aboard or in the chandlery cupboard: the correct rearming kit for each jacket, a spare cylinder, O-rings, a bobbin or cartridge if applicable, a crotch strap, and a spare light battery. Label the kits with the jacket model. There is nothing saltier than discovering at dusk that the spare cylinder fits the other jacket.

A routine that takes less time than a tide wait

Before the season: weigh, inspect, orally inflate, fit and record the date. Before a passage: check the indicator, toggle and fit. After a soaking or a firing: rearm properly. That is it. Not a grand ceremony, just a habit. Safety kit is only safety kit if it has been weighed, tested and fitted properly. The rest is just luggage with a whistle.