Features October 1, 2001 Issue

PFDs Set Straight

Confused about today’s growing number of types and styles of life jackets? No wonder. Outdated and misleading information abounds. Here's a primer on the rules, as well as some common-sense advice.

Personal Flotation Device, or PFD—the thing you used to call a life jacket—is probably the single most important safety aid you can use on your boat. And yet it's one of the least understood. A PFD can save your life if you fall overboard (if you're wearing it). Any PFD is much better than none, but there are some significant differences among them. What's more, the number of different kinds of PFDs has increased drastically over the past few years, and the most widely available source of information (the little USCG booklet called "Think Safe" that is attached to every USCG-approved PFD) is often several years out of date and contains some misleading information. There's more current information from the Coast Guard on the Internet, but it can be hard to find. 

Type II PFDs may or may not turn people over.
This tester jumped into the pool, went limp,
fell forward, and would have stayed that way.

Essentially, a PFD's main job is to make you take up more space in the water. A body (or anything else for that matter) that's submerged in the water pushes aside, or displaces, a volume of water equal to the volume of the submerged object. If the submerged object weighs more than the volume of water displaced, it will sink. If it weighs less than the volume of water displaced, the object will float, rising above the surface until the volume of water displaced weighs the same as the object.

The PFD's effectiveness in displacing water is expressed in "pounds of flotation." A gallon of water, for example, weighs a bit over 8 pounds. An empty gallon jug or can will displace a bit over 8 pounds in water if you submerge it, providing a bit over 8 pounds of flotation. The shape of the container makes no difference; only the volume counts.

The density of the human body is close to that of water. A typical adult, completely submerged except for the head—and with all air exhaled—needs only an extra 7-12 pounds of buoyancy, depending upon body type, clothing and dry weight.

A PFD provides that lift, plus some more for higher lift and to provide insurance against an unusual body type sinking. The bulk of flotation required to accomplish this is the same no matter how the jacket is designed or where the bulk is located. Additional volume means additional lift, but only up to a point. It only works as long as that additional volume is submerged—the portion of the PFD that's out of the water doesn't raise you any higher (although it can provide some reserve buoyancy if a wave comes along). The phrase "Higher buoyancy means higher lift," found in the Think Safe booklet attached to a PFD we bought, should be taken with a grain of salt.

Any PFD can keep you from sinking, but it may not keep you from drowning. If the PFD doesn't float you with your face up, it's up to you to keep your face out of the water. The most effective PFDs have what is known as a strong righting moment—their bulk is located in the chest area, to lift that up, while the remainder of it is behind the neck, to keep the head from sinking. A PFD with a strong righting moment will keep your body angled in the water with your feet down and your head and face up, with no effort on your part, whether you're conscious or unconscious.

The third area that a PFD helps with is the avoidance of hypothermia—a serious condition in which your body loses so much heat that your body temperature drops to dangerous levels. Many sailors don't know that hypothermia can be a hazard to anyone immersed in water colder than skin temperature (86 degrees F or so). Obviously, the colder the water, the greater the risk. Any activity in the water increases the flow of blood to the skin, increasing skin temperature and consequent heat loss. Since water is a much better conductor of heat than air, the more of your body that's under water, the greater the risk.

One benefit of a good PFD is that it floats you higher in the water; another is that it allows you to minimize body motions. Still another is that it permits you to assume the so-called HELP (Heat Escape Lessening Posture) position with your knees drawn up to your chest and your arms wrapped around your knees or trunk.

The HELP position can dramatically extend the time you can survive in the water, but it's impossible to maintain without a PFD or with one with an insufficient righting moment.

Legal Requirements
If you're boating in US waters, USCG-approved PFDs are required. All recreational boats must carry one wearable PFD (Type I, II, III or V) for each person aboard. A Type V only meets the legal requirement if it's used according to specific label instructions—generally requiring that it be worn. Types I, II and III PFDs need only be carried aboard, hopefully in a readily accessible place.

In addition, any boat 16 feet or longer (excluding canoes and kayaks) must carry at least one throwable (Type IV) PFD.

It should be noted that these requirements, like all USCG legal regulations, are minimum requirements. There's nothing to stop you from carrying (and using) anything else you may wish to use. In fact, as long as you have the required number of approved PFDs aboard, there's nothing in the law that prevents you from actually using a non-approved device. This was a practice that was often followed prior to the USCG's approval of inflatable PFDs, when boaters wished to take advantage of inflatables' superior wearability and flotation.

The Coast Guard has defined several different classes, or types, of PFDs. Each has a specified minimum amount of flotation and a minimum righting moment. Until recently, all approved PFDs were of "inherently buoyant" construction—the PFD was as bulky when stored or worn as it was in the water. The approval of inflatable PFDs has created a fair degree of confusion among boaters as to which type does what, since the Coast Guard standards attempt to compensate for the inflatables' higher maintenance requirements (and possible lower reliability) by demanding higher levels of performance from them when they're working properly. The USCG provides recommendations for which type to use under varying conditions—recommendations that we find to be somewhat problematic. In any case, here are the types.

Type I inflatable
A new standard for a Type I inflatable has been released recently. Unfortunately, no Type I inflatables have been approved. Unlike an inherently buoyant Type I, an inflatable Type I is comfortable to wear even in hot weather and provides little restriction to free movement when not inflated. With a minimum inflated flotation of 35 pounds, this is the best performing PFD of all types. It will turn virtually any wearer face-up. Its two separate chambers inflate automatically when submerged, or can be inflated manually or orally. The inflatable Type I's specification requires that the PFD have a highly visible color when inflated.

It's an adult-only PFD, with one size fitting all adults. Like all automatic inflatables, it's not suitable for use when immersion is expected, as when whitewater paddling, riding personal watercraft, or while water-skiing. Like all inflatables, an inflatable Type I requires regular inspection and proper rearming and maintenance; an uninflated one will not provide flotation.

Type I (non-inflatable)
According to the Coast Guard, a Type I is "best for open, rough or remote water, where rescue may be slow coming." A Type I PFD is big and bulky—you may have seen them on ferries. They provide at least 22 pounds of flotation, with most of it located in the chest and belly area. It will turn the vast majority of unconscious wearers face up and has sufficient reserve buoyancy to keep waves away from the wearer's face. Type I PFDs come in two sizes to fit most children and adults. They require little or no maintenance, except for periodic inspections for rips or tears. A Type I fits like a vest, with a back that helps prevent heat loss that leads to hypothermia.

A Type I would probably be the ideal PFD except for one thing: Its bulk is great enough to make it almost impossible to get anyone to wear one unless the boat is actually sinking. For the recreational boater, a Type I is just not a feasible option.

Type II (non-inflatable)
"Good for calm, inland water or where there is a good chance of fast rescue." A Type II is the kind of PFD that most boaters picture when they hear the word PFD. It's a scaled-down version of a Type I with a minimum of 15.5 pounds of flotation—again concentrated in the chest area (with a collar of flotation material at the back of the neck) to help turn unconscious wearers face-up.

Several years ago, Type IIs were claimed to be capable of doing just that. Today, while the Type II hasn't changed, the claims have become more realistic: "Turns some unconscious wearers face-up in the water." (italics ours). The "some" is important to remember; our tester was surprised to find that a Type II could easily leave him face-down in the water (see photo, page 13). The righting moment of a Type II is noticeably less than that of a Type I. The flotation material in a Type II used to be kapok, a naturally occurring vegetable fiber. The kapok in a PFD can become waterlogged if the protective plastic bag that covers it is ruptured; more recently, slabs of closed-cell plastic foam have replaced the kapok in Type IIs.

Type II PFDs come in a variety of sizes: Infant, Child-Small, Child-Medium and Adult. The Coast Guard notes that they're not recommended for long hours in rough water. This is due in part to the fact that a Type II has no back, and heat loss can be a problem. It's also due to the fact that even small waves wash over the wearer's head. There are no Type II inflatables.

Type III (non-inflatable)
The Type III PFD was introduced in 1971 in recognition of the fact that a somewhat less safe PFD that's being worn is more apt to save your life than a safer one that's not being worn. In a move to encourage boaters to wear their PFDs instead of stowing them, the Coast Guard approved Type IIIs, which trade off righting moment for wearability (and, not inconsequentially, style). Like the Type II, a Type III provides a minimum of 15.5 pounds of flotation; unlike a Type II, this flotation is distributed fairly uniformly around the entire PFD. As a consequence, a Type III is less bulky, more comfortable, and permits greater motion. As a less desirable consequence, a Type III has little or no inherent righting moment, leaving it up to a conscious victim to keep his or her face out of the water.

When we tried a Type III in a pool, our tester needed to make constant small corrections to keep breathing air, and not water. He found it impossible to remain in the HELP position.

Although a Type III carries the same recommendation for use as a Type II—"Good for calm, inland water, or where there is a good chance of fast rescue"—a Type III provides less protection than does a Type II. Type IIIs are made in a wide variety of styles—vests, jackets and float coats—and colors. They usually provide a smaller range of size adjustment than Type I or Type II PFDs, so they're available in a wide variety of sizes to fit wearers from Child-Small to Adult-Large.

Type III inflatables
An inflatable PFD provides no flotation until it's inflated. The Coast Guard's longtime reluctance to approve this type of PFD was due to concerns about the reliability of the inflation mechanisms. Although inflatable PFDs have been in existence for over a half-century, approval for meeting the carriage requirement didn't happen until 1996; approval for automatic inflatables was granted in 2000.

The performance characteristics required of an inflatable are considerably more stringent than those of an inherently buoyant PFD. An inflatable Type III PFD must meet the buoyancy requirements of a Type I non-inflatable. In our pool tests, the inflatable we tried kept our tester afloat, face-up, and comfortable without the need for moving arms or legs. (It was a Type V, which is identical to a Type III inflatable once inflated—see below.) An inflatable, even more than a non-inflatable Type I, keeps you face-up forcibly enough to makes swimming impractical unless you do a backstroke.

The chief advantage of an inflatable is the dramatic difference in bulk between an uninflated PFD and one that's inflated—a difference that can't exist with a non-inflatable. As a result, an inflatable is generally the most comfortable type to wear continuously, particularly in hot weather. While inflatables can be made in a variety of styles, the most popular is a physically small "shawl" design. Inflatables are only approved for use by adults (over 16 years of age), presumably because the Coast Guard feels that children may be unable to cope in an emergency. For adult users, one size fits all. They're not suitable for whitewater kayaking, water skiing or use on PWCs.

An inflatable Type III is required to provide at least 22.5 pounds of flotation when inflated. (Many models provide a whopping 35 pounds.) Inflation is accomplished by pulling a lanyard, which pierces the seal on a high-pressure CO2 cartridge. As a back up, there's an oral inflation tube provided. Righting moment of a Type III inflatable is at least as high as that of a Type I. Because a manually operated inflatable PFD requires a positive action by the wearer to inflate it, it provides no help to an unconscious (or badly panicked) man overboard.

Type IV
A Type IV PFD is not wearable—it's a throwable flotation aid such as a ring or horseshoe buoy or a flotation cushion. A type IV is required on vessels 16 feet or more in length; it's recommended for any vessel that carries more than one person. Type IVs, no matter how many you carry, do not satisfy the requirement for having one wearable PFD per person aboard. Ring buoys provide a minimum of 16.5 pounds of flotation; flotation cushions provide 18 pounds.

Type V
A Type V PFD satisfies USCG legal requirements only under particular sets of conditions. They include boardsailing vests, deck suits, whitewater vests, automatic inflatables and hybrid inflatable vests. The most common condition for approval of a Type V is that it must be worn to meet legal requirements, although others exist and are specified on the PFD's label.

Hybrids—inflatable PFDs with some inherent buoyancy—were the only approved inflatable PFDs until 1996. A hybrid has less inherent buoyancy than a comparable non-inflatable but carries enough to help keep you afloat while you inflate the non-inherent portion of the device's buoyancy provision. Once inflated, the performance of a hybrid is comparable to that of a Type I, II or III (read the label to see which). The hybrid PFD sounds like a way of having your cake and eating it too, but it doesn't seem to have caught on widely. That’s likely because, while it combines some of the good features of inflatables and non-inflatables, it also combines several of their less-desirable ones. A Type V hybrid is only slightly more wearable than a Type III non-inflatable, especially in hot weather, while no more reliable than a Type III inflatable (the 7.5 pounds of inherent flotation is borderline minimal, or worse).

The automatic inflatable is another kind of PFD that is classed as Type V. Automatic inflatables have been—and still are, to some extent—the subject of a good deal of controversy. A Type V automatic inflatable PFD is typically identical to the same manufacturer's manually inflated Type III, except that it will automatically inflate when submerged. A water-soluble "pill" softens upon immersion, allowing a spring-driven piston to penetrate the seal on a CO2 cartridge. Automatic inflatables, like their manually inflatable siblings, have a lanyard that can be pulled for manual inflation as well as an oral inflation tube. The automatic-inflatable PFD is a Type V, approved only if worn; the manual-only version is Type III. While many feel that the automatic features in no way make the PFD less safe, the Coast Guard and United Laboratories, which does the actual testing, disagree.

To quote Daniel Ryan, Engineering Services, Research Triangle Park, a member of the committee that met to establish standards for automatic inflatable PFDs: "PFDs with automatic inflation systems are also required to have a manual (lanyard) inflation system and an oral inflation system. Some members of the ad hoc committee argued that an automatic inflatable that fails to operate is still as 'safe' as a manual inflatable due to the presence of the manual inflation system. UL and the USCG disagree with this view, because PFD users may rely on an automatic inflation system as their sole means of survival. A user who is unable or uncomfortable with the need to pull a lanyard in an emergency may select an automatic device. Clearly, if an automatic inflation system is provided, it must function reliably."

We find it strange that a feature that allows an inflatable to work if the wearer is unconscious or incapacitated could somehow make for a less-safe PFD, but in any case we're happy to see automatic inflatables accepted, regardless of the requirement that they must be worn.

There are some drawbacks to the automatical inflatable, chief among them the fact that it will self-inflate if the part that holds the triggering mechanism is submerged or simply doused or drenched with enough water to set it off. There are already plenty of stories about the things going off by surprise in benign situations. For obvious reasons they're not well-suited to many small-boat situations or, perhaps, to foredeck work in heavy conditions.

Recharging the PFD after it's been used is slightly more involved than dealing with a non-automatic model; the same requirements for periodic testing and examination exist for all inflatables, automatic or not.

Conclusions and Recommendations
As the Coast Guard has succinctly put it: "In terms of risk of drowning, the safest Personal Flotation Device (PFD) is the one you're willing to wear." It's also important to remember the truism that most people are injured or drown in "safe" situations. That said, we feel that the decision whether to wear a PFD at all times on deck, or only when you perceive a potentially risky situation developing, is a personal one, and should remain that way (excluding the times you're under the "external" command of a vessel's captain, or following the requirements of a race committee, etc.).

The most important thing is to find a PFD that you're comfortable in both physically and mentally, and that you'll wear willingly. If you have a particular fear of being knocked unconscious by the boom, you may decide that an automatic inflatable is right for you. On the other hand, you may find its auto-inflation function so inconvenient when you get wet that you become reluctant to wear it. That would be the wrong PFD.

We do feel that inflatable vests, be they manual or automatic, will be the best choice for most adults. (Inflatable-only PFDs are not yet approved for children, although Sospenders now makes a Coast Guard-approved hybrid inflatable/inherent flotation model in child and youth sizes.) Aside from providing maximum comfort and minimum bulk when uninflated, most inflatables, when deployed, will float you higher and maintain you in a face-up position better than a corresponding inherently buoyant model of the same type designation.

In any case, the final test of any PFD should be one you do yourself. Put it on like you mean it—it should be snug enough not to ride up when you hit the water (there have been cases in which a MOB simply slipped out of a PFD in the water and drowned). Then jump in and see how it keeps you afloat. Let your body go limp in a face-down position and see if it will turn you over. If you're using an inflatable, you can inflate it orally and not waste a cartridge; if you're testing an automatic inflatable, you can disarm the triggering mechanism before you enter the water.

If you're not going to wear your PFD as a regular practice, at least try donning it in the water. This is a more difficult task than most people suppose, even assuming that you're conscious, and that whoever's on board knows where the PFD is and can get it to you. Then put your name on it prominently, and store it in a safe, accessible place.

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