Both PFDs and Life-jackets provide buoyancy, they differ in their buoyancy requirements and distribution. By definition a PFD "is intended for constant wear to increase the safety of adults who are required to be physically active in situations where drowning hazards exist." This differs from a life jacket in that a life-jacket is rarely worn, and used primarily in an emergency situations.

Life-jackets are designed to keep an unconscious drowning victim floating on his back with the face out of the water. To accomplish this, approximately 80% of the buoyancy is distributed in the front of the jacket. The in-water performance is excellent; however, when worn out of the water the Life-jacket is very awkward and uncomfortable.

PFDs on the other hand are designed to keep conscious wearers safely afloat. As the wearer is assumed conscious and able to assist in their own rescue, the requirements for PFDs allow for less buoyancy, with approximately 60% of the buoyancy being distributed in the front. The in-water performance of a PFD is therefore inferior to that of a Life-jacket; however, when worn out of the water the increased comfort of the PFD makes it more suited for a constant wear situation.

This comfort is obtained at the price of your safety and the result, as advised in the Coast Guard instructions which accompany every PFD offered for sale; "It may have a slight tendency to tilt the wearer, when vertical in the water, face down."

Challenges
My major challenge was to improve the buoyancy characteristics of the PFD. Through a series of intricate tests, using variable inclinometers designed expressly for this purpose, comparisons were made to evaluate the buoyancy distribution changes necessary in the Helm PFD to make it perform more like a life-jacket without sacrificing comfort.

This was accomplished by distributing the foam in various thickness and volumes throughout the front of the jacket thereby changing the centre of buoyancy and eliminating much of the wearer’s tendency to be turned face down in the water. Not only did this result in a more desirable floating position, but it also provided hand protection for the angled hand-warmer pockets.

Another challenge for us has not been widely appreciated until relatively recently. Death by drowning can, in even mild wind and wave conditions, be caused purely by wave splash and spray, regardless of whether the victim is wearing a flotation device.

To overcome this problem I designed a splash guard. This splash guard which incorporates a clear face visor for visibility is made from durable waterproof, breathable fabric. It is attached to the hood interior and can be brought into use quickly and simply by unrolling the hood and placing the splash guard over the head. Ventilators in the sides allow the wearer to breath easily, with no undue CO2 build up.

Special Features
Anyone immersed in cold water or air can succumb to hypothermia in minutes. Hypothermia occurs when the deep body temperature drops from the normal 37 degrees C (98 degrees F) to approximately 32 degrees C (89.6 degree F). The cause of death is usually cardiac arrest and occurs when the core temperature falls below 30 degree C (86 degree F).

A significant amount of heat is lost through the head, therefore Helm’s PFD comes equipped with a hood which conveniently rolls out of the high collar. The hood is constructed with material that retains 80% of its insulative properties even when wet. Additional insulation is used over hypothermic vulnerable body areas such as the ears and forehead. As mentioned previously the hood also contains a splash guard to prevent drowning from waves and spray, and a retroreflective strip for night recovery.

A series of drainage grommets are installed on the inside of the lower back section of the jacket. These allow water to seep out of the PFD as the wearer is lifted out of the water. Without the drainage holes, the extra weight of the water may make a rescue, particularly a self rescue, difficult. A safety harness is also incorporated into the PFD and is readily available inside the external zip pockets.

Materials
The components of the PFD have been carefully selected. They include a very soft unicellular foam, which has a high rate of buoyancy per volume. This contributes to a lighter more comfortable PFD. The PFDs interior is lined with polypropylene to draw moisture i.e. perspiration away from the body where it can evaporate. This keeps the PFD comfortable over an extended period of wear. Areas of the PFD that are subjected to heavy wear have been constructed with Cordura, a sturdy abrasion-resistant material.

Distinguishing Features
In essence, the Helm PFD is unique with its self-contained safety features, functional design and esthetic appeal! The attractiveness and comfort of the Helm PFD encourages individuals to wear it, thereby giving an overboard victim an improved chance of survival!

Use
Early prototypes of the Helm PFD were given the ultimate test during Jeff MacInnis's historic Polar Passage Expedition in the Canadian Arctic. Continued refinements have resulted in product features used in many recreational and commercial coat and suits applications."