Inflatable life jackets are the most common choice for offshore sailors, but because there’s a bit more to them than a traditional foam life jacket, it’s important to know how they work and how to maintain them. 

Inflatable life jackets work by an inflation system triggering a spring that punctures a CO2 cartridge. These systems are activated either by a capsule that dissolves when wet, allowing the spring to trigger, or by water pressure. Spinlock’s Hammar inflation system, for instance, will not inflate until the cylinder cap is about 4 inches below the water. The advantage of this system is that jackets won’t accidentally inflate because of rain or spray, but the disadvantage is that bouyant clothing can delay inflation. Sensor inflators are usually designed to only inflate when water flows upward into the cap, but these are known to accidentally inflate.

Most offshore inflatable life jackets also have the ability to switch to a manual-inflation-only setting. This typically requires removing the firing cylinder, rendering the auto-inflate function useless. If a life jacket has been set to manual inflation, it will inflate only when the handle or pull tab is firmly pulled. Life jackets that have been set to manual only should be clearly marked.

It’s important to make sure a life jacket fits properly, first by purchasing the correct size for the wearer (although most fit quite a wide range of people), and secondly by fine-tuning the fit. The waist strap (which usually fits around the rib cage) should be snug but still allow for movement. Other aspects of the fit will vary depending on the model, so read the life jacket’s manual and look for online fit videos to make sure it is adjusted properly. The fit will also need to be adjusted differently depending on what is worn underneath it. 

Many life jacket models come with extra safety gear: integrated harnesses, leg straps, sprayhoods, lights, whistles and tether cutters. Wearers should locate all of these features and familiarize themselves with how they work. All inflatable life jackets, no matter what color they are on the outside, inflate to a high-visibility color. 

Once a life jacket has been properly fitted and all of the extra equipment has been reviewed, spend an adequate amount of time reviewing how it inflates, as this is, after all, the most important feature. Know where the manual inflation pull handle or tab is because if the jacket does not inflate, it will be up to the wearer to inflate it. You should also locate the inflation tubes, which can be used to add air to the jacket as needed or used to fully inflate if the CO2 cartridge fails. 

And of course, it’s important to maintain life jackets. Salt and dirt should be removed with a damp sponge and the jacket should be thoroughly dried after wearing. Life jackets should be inspected annually and CO2 cartridges and arming mechanisms need to be replaced or reset anytime the life jacket is inflated. Manufacturers offer detailed information on how to re-arm life jackets, both in written instructions and videos.

If you are planning to re-arm your life jacket anyway, an excellent exercise is to jump into a swimming pool with it on to get a real feel for how the jacket functions. You may feel it is worth the cost of a re-arming kit (usually about $50) to practice using a life jacket.