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Your Immersion Suit: Don’t Depend On Label Size For a Good Fit!

Editor's Note: This article originally was published in the Spring 2012 edition of Marine Safety Update.

It is a myth that a "universal size" immersion suit will fit all persons weighing between 110 and 330 pounds. Above left, a "universal" immersion suit is much too large for this wearer who is 5'6" and weighs 133 pounds. At right, this person who is 5'5" and weighs 245 pounds cannot even close the zipper of the same "universal" suit.

The loss of life resulting from the 2008 sinking of the Alaska Ranger and other vessels demonstrated the possible consequences of loose fitting or too tight immersion suits, especially in hazardous ocean conditions. Designing an immersion suit that fits a wide range of human body shapes is a major challenge. The size ranges indicated on immersion suit sizing labels are not dependably accurate and can be misleading to people buying suits. For example, a “universal size” immersion suit is labeled as fitting persons weighing from 110 to 330 pounds. However, most people under 140 pounds or over about 245 pounds will find that this size immersion suit will fit very poorly or not at all.

Looking at it another way, over 50% of the labeled 230-pound range of universal sized immersion suits is inaccurate. Pictured above are two people, both well within the stated 110-330 pound size range of a “universal size” immersion suit. However, neither of their “universal” suits fit!

In AMSEA’s experience, training thousands of people wearing immersion suits in the water, the hood of a “universal” suit that is too large for a 130 pound person will tend to float off the wearer’s head, allowing a large volume of water to enter the suit, potentially causing hypothermia or drowning. In addition, a too-large suit makes it difficult to hold onto objects since the hands will not reach the gloves or mitts of the suit. Of equal concern, a “universal” suit that is too small for a 265 pound person will not even zip closed.

After a vessel casualty in ocean conditions with waves and wind chop, even a well-fitting immersion suit can make for a test of survival. One way to tilt the odds in your favor is by trying on immersion suits before buying one, especially if you are in the lighter or heavier range of the sizing label. Also, note that different brands of immersion suits have slightly trimmer or wider cuts. One brand may fit you better than another even though they are both labeled “universal.” Few would buy a pair of $100 shoes without trying them on. Why would you buy a $400 immersion suit without doing the same?

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