There are different types and classifications of life jackets. You should know about these to best determine what you need for your type of boating. For example, a vest suitable for riding about on a PWC might be very inadequate for use on an offshore vessel which should have Type 1 life jackets. And having a proper life jacket aboard may not help at all in many circumstances if you don't have it on. Fortunately, inflatable life jackets are not only approved for many uses but are more comfortable and convenient and thus more likely to be worn. For a discussion of the types see the relevant section of a BoatUS Foundation Findings Report. As of summer 2012 the Coast Guard and other authorities are considering making some changes to the standards in the future, so stay tuned.
A significant difference between inflatable PFDs and inherently buoyant vests, such as those filled with foam, is that they are more comfortable and less cumbersome to wear. They are lightweight and tend to be much cooler in hot weather. Less cumbersome can contribute to increase safety in that the PFD is less likely to interfere with things that you have to do on a boat, when you're wearing it. Also, people are more likely to wear it.
However, inflatables are not necessarily for everyone. They are not recommended for children. Also, they are more expensive and require maintenance. Inflatables contain a CO2 cartridge that inflates the vest. Manual/automatic models can be inflated manually with a ripcord, and also inflate automatically upon contact with water. Manual only models require the wearer to pull a ripcord to activate inflation. This cartridge must be properly installed and replaced with a new one after the vest has been inflated and periodically as a matter of maintenance. It is required that indicators show whether the CO2 cartridge is properly installed and ready for use.
Inflatable PFDs should include an extra CO2 cylinder and cap in an inside pocket. This lets you rearm it immediately if you accidently inflate the vest. The included kit may rearm it as a manual model, meaning it can be reinflated only by pulling the ripcord. This is intended for emergency use. We also recommend having a complete rearming kit onboard for each inflatable, which will allow you to rearm it completely as a manual/automatic. Most vests have been designed to make rearming simpler, and include detailed written and illustrated rearming instructions. Your inflatable should also contain an oral inflation tube so a MOB can maintain buoyancy for an extended period of time by blowing into the inflatable, if necessary.
It is extremely important to thoroughly understand the manual for your inflatable and to carefully follow all maintenance and replacement instructions.
The BoatUS Foundation for Boating Safety conducted a three-year study that involved 520 volunteer boaters using eight different models on the market from 1990-93. The majority of boaters using the devices in all types of boating and waterways said they liked the wearability of inflatables and would choose one in an emergency over a traditional life jacket. Participants overwhelmingly liked inflatables because they were more comfortable.
In May 2011 the BoatUS Foundation conducted a study on life jackets in general, including inflatables.