What to know when buying a life jacket.
Whether you are a seasoned sailor an occasional boater, there is one piece of safety gear you can’t afford to ignore: the lifejacket.
But gone are the days when your only option was a bulky, orange foam block that made you look like a poorly rendered video game character. Today’s inflatable lifejackets are sleek, comfortable, and packed with life-saving tech.
We'll break down exactly what a lifejacket is, how to choose between the two main types, and how to keep yours in tip-top shape.
What Exactly Is an Inflatable Lifejacket?
While traditional foam lifejackets (often called Personal Flotation Devices, or PFDs) rely on inherently buoyant materials, an inflatable lifejacket remains uninflated while you wear it. It sits flat against your chest and shoulders, giving you maximum freedom of movement.
When triggered, a small cylinder of compressed carbon dioxide (CO2) punctures, instantly filling the internal bladder with air and turning you into a floating beacon of safety. They are designed not just to keep you afloat, but to actively turn an unconscious person face-up in the water.
Manual vs. Automatic: What's the Difference?
When buying an inflatable lifejacket, you will face a crucial choice: Manual or Automatic. Neither is objectively "better" than the other; it entirely depends on what you are doing on the water.
| Feature | Manual Lifejackets | Automatic Lifejackets |
| How it inflates | You must manually pull a toggle/cord to puncture the CO2 cylinder. | Inflates automatically within seconds of being submerged in water. |
| Best for... | Anyone who expects to get wet or splashed often. | Cruisers, night sailors, or anyone who wants a fail-safe backup. |
| The Pro | Zero risk of accidental inflation from heavy rain, big waves, or damp storage. | If you hit your head and fall into the water unconscious, it saves your life. |
| The Con | If you are knocked unconscious or injured when falling overboard, it will not inflate. | Can accidentally inflate if stored in a very damp locker or hit by a massive wave. |
Pro Tip: Many automatic lifejackets also feature a manual backup cord and an oral inflation tube, giving you three ways to get air into the bladder if things go sideways.
The Third Option: Hammar (Hydrostatic) Systems
If you’ve been shopping for a high-end offshore lifejacket, you’ve probably run across the name Hammar.
Hammar isn't a brand of lifejacket itself, but rather a specialized type of automatic inflation technology called a Hydrostatic system. It bridges the gap between manual and traditional automatic systems, solving the biggest annoyance of standard automatics: accidental inflation.
How a Hammar System Works
Traditional automatic lifejackets use a small, water-soluble paper bobbin or capsule. When it gets wet, it dissolves, releasing a spring that punctures the gas cylinder.
A Hammar system completely ditches the dissolving paper. Instead, it uses a hydrostatic valve that measures water pressure. The lifejacket will only inflate when it is submerged under roughly 10 cm (4 inches) of water.
The Pros:
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Zero Accidental Inflations: Because it relies on water pressure rather than moisture, you can be hammered by heavy rain, blasted by ocean spray on the bow of a boat, or leave it in a damp locker, and it will never accidentally go off.
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Corrosion Protection: In a Hammar system, the CO2 cylinder is actually stored inside the lifejacket’s inflatable bladder. This protects the metal cylinder from salt air and moisture, virtually eliminating the risk of rust and corrosion.
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Longer Shelf Life: Standard automatic paper bobbins typically need to be replaced every 2 to 3 years. A Hammar hydrostatic mechanism generally has a unique 5-year lifespan before the firing head expires.
The Cons:
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Cost: Hammar systems are more expensive upfront, and the re-arming kits cost significantly more than standard paper capsule kits.
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Slightly Delayed Trigger: Because you have to sink 10 cm underwater for the pressure valve to open, there can be a tiny, split-second delay in inflation compared to standard automatics that fire the moment they touch the water's surface.
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Tricker to Re-arm: Replacing a spent Hammar system requires a specific plastic key (included in the kit) and a bit more manual dexterity than just screwing in a new cylinder.
Who is it for?
Hammar systems are the gold standard for offshore sailors, ocean racers, and commercial boaters who operate in extreme, wet environments where standard automatic jackets might accidentally deploy.
How to Service Your Lifejacket (Because a Dead Battery Won't Save You)
A lifejacket is a piece of safety equipment, not a fashion statement. If you don't maintain it, it’s just an expensive vest. You should have your lifejacket professionally serviced every year, but you should also perform regular DIY checks.
Here is how to do a standard self-inspection before the boating season kicks off:
1. The Visual Inspection
Unzip or un-velcro the outer protective cover and inspect the internal bladder. Look for any signs of fraying, tearing, or wear. Check the straps and buckles to ensure they click together securely.
2. The 24-Hour Leak Test
Locate the oral inflation tube (the little plastic pipe). Blow up the lifejacket completely using your mouth (or a hand pump if you want to avoid moisture buildup inside) until it is firm. Leave it in a room with a stable temperature for 24 hours. If it loses pressure or goes soft, you have a leak, and the bladder needs to be replaced.
3. Check the CO2 Cylinder
Unscrew the CO2 gas cylinder and inspect it.
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Is it rusted or corroded? Replace it.
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Weigh it on a kitchen scale. The correct weight is printed right on the cylinder (e.g., "33g"). If it weighs less than the printed total weight, the gas has leaked, and it's useless.
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Look at the end of the cylinder. If there is a hole in it, it has already been fired and needs to be replaced.
4. Check the Firing Mechanism
If you have an automatic lifejacket, check the firing capsule (often a paper bobbin or a hydrostatic system). Look for an expiry date. If it’s past that date, the chemical mechanism can degrade, meaning it might not fire when wet—or worse, fire randomly while sitting in your closet.
Once everything is checked, green indicators on the firing mechanism should tell you the jacket is "armed" and ready to go. Deflate the jacket completely by reversing the cap on the oral tube, pack it away neatly according to the manufacturer's instructions, and you're good to go.
The Golden Rule
The most important thing to remember about a lifejacket? It only works if you wear it.
Investing in a high-quality, comfortable manual or automatic lifejacket means you won't have an excuse to leave it on the boat floor. Stay safe, respect the water, and check your gear!