Survival Training Part 5: Immersion Suits

Survival training, Part 5: Immersion suits.

You will recall we wrote some time ago about our decision to carry dry suits for the two of us for both in-the-water maintenance and emergency use – the latter in lieu of immersion suits. This decision was made after discussing the subject with a number of experts, and considering our needs, but without the benefit of real world testing of immersion or dry suits.

As part of the survival training course we just went through, the use of immersion suits was taught. This started in the classroom and ended up in Sitka Harbor, off the stern of Wind Horse. We’ll discuss our thoughts on survival and immersion suits at the end of this article.

Before we start we want to make a general point about the situation you are in if you are considering the use of this gear. By definition this indicates an abandon ship scenario is imminent. To enhance your chances of survival a formal abandon ship procedure needs to be in place, and practiced – even if there are just two of you aboard. This includes getting out a "May Day" message, bringing abandon ship equipment where it is ready to deploy, and fighting the problem so that you do not have to get off the boat.

Immersion suits are required on commercial fishing vessels in these waters, and they have saved many lives. There have also been tragic losses through the misuse of the suits. Knowing how to use this gear under duress is a life and death issue. Which is why practicing with them is mandatory for the boats required by law to carry them.

using an immersion suit

This is Ryan, one of our classmates, demonstrating the correct way to get into an immersion suit. He starts with the suit under him, sitting on the deck. Shoes or boots are often worn, and it is much easier to get into the legs of the suit if you place a plastic shopping bag over each foot. (Bags are stored in the hood of the suit.)

getting into an immersion suit

One leg is slipped in.


Then the second leg.


Next you pull the legs up onto your torso.


Your weak arm (left if you are right handed) is then placed first into the suit.


Standing now, Ryan pulls the hood over his head using his still free (strong) arm. Do not wear a hat or sweat shirt hood under the survival suit hood as it will cause the survival hood to slip off.


With the hood and weak arm in place, the strong arm is slipped into the immersion suit. If you should forget, and put both arms in before the hood is in place, someone else will have to put the hood on as you won’t have the mobility now to do it yourself.

immersion suit zipper

The zipper is then pulled up to make you watertight.


Note this suit has a handle at the bottom of the zipper as well as one on the zipper slider. It is not easy to work these with the three fingered suit Ryan is wearing.

immersion suit glove styles

Which is one of the reasons our instructor, Dug Jensen, prefers a suit designed with a five fingered glove. From our brief experience with both types, we can see why.


The last step is to reach the hose that inflates the air bladder, and blow into it. On this suit the bladder is in the form of a girdle. Other suits have the bladder as a pillow on your back.

immersion suit floatation

Ryan’s girdle style bladder is attached with zipper, which can come undone. Dug suggests seizing the zippers in place with needle and thread.


The final step is to tighten the ankle straps, which Dug is doing for Ryan.

immersion suit drain valves

Here’s another detail. These suits all have some sort of a bleeder/drain system in each foot. This one has a check valve, which is easily fouled – in which case it leaks.


Other designs, like this suit made by Stearns, include a tiny slit for drainage, which Dug prefers. You will also want to look at whether or not there are pockets for lights/strobes, some form of harness for tying yourself to others or to use as a lifting sling, and zipper operation. Linda had a hard time closing her zipper because of its stiffness. Zipper maintenance, using a special wax, should be carried out (as a minimum) at the beginning and end of each season.

It surprisingly easy to don these suits, even for cruisers of advanced age, in the classroom. There’s plenty of room, the floor is stable, and it is dry. Switch to the cockpit of a small sail or powerboat, and this is going to become more difficult. Not impossible, but a lot harder. Which is why practicing periodically with this gear, in the part of the boat where in the real world you might be really be doing it in an emergency, is a good idea.

Steve and Linda Dashew in immersion suits

Here is the photo you’ve been waiting for – your intrepid reporters kitted up and ready for the cool Sitka, Alaska waters. Linda’s suit is too large for her and very hard to maneuver. Steve’s hood does not fit correctly and the flap will not stay closed across the chin (these are borrowed immersion suits). If you have this gear, you need to make sure it fits properly. These two problems would shorten the period we could survive in the water.

floating in an immersion suit

Once you are afloat there is not much you can do, other than float on your back. There is just too much buoyancy.


The two of us in the water, locked together with Steve’s legs around Linda’s torso. Linda’s girdle floatation can be compared with the pillow float on Steve’s back. There seems to be more freeboard with the back pillow, keeping Steve’s head higher above the sea-level.


This is Carter Hughes, a commercial fisherman, testing a different type immersion suit. You have the ability to do more work in this suit but it appears a little harder to get into and the gloves are not built in, so they leak.


Bo Abbjorn has joined Carter and the two of us to demonstrate how to get somewhere using the centipede approach. We’re locked together, legs around torso, and by stroking our arms in unison can make much better progress than is possible individually. We also have good directional stability.

Now the hard part: What to carry? If you are going to cruise the cold country, we feel some form of protection for emergencies should be aboard. You are not going to last very long in a life raft without a means of staying warm and dry. Your odds of survival are orders of magnitude greater with this gear than without. Survival for 24 hours in Alaskan water (without a raft) is possible with an immersion suit. Without it, you might make it for two or three hours and possibly a lot less.

The immersion suit has the advantage of being quick to get into compared to the dry suit which is designed for diving. But you have to practice getting into the suit with regularity – your life could depend on this.

We were pleasantly surprised at how much mobility we had on deck and in the water in the immersion suit. A lot more than we had imagined just by looking at photos. On the other hand, wearing the immersion suit for any length of time in a life raft (more on rafts shortly) seems like a pretty awful concept (unless there is no choice). Dug suggested pulling the suits around our waists while in the life raft, and putting them back on if we had to exit the life raft, or if the risk of raft capsize was present.

The dry suit is more comfortable, gives you a lot more mobility to work aboard fighting whatever the problem is, and seems easier to live with in the confines of a life raft. But it takes longer to get into. You have to put on your insulating thermals, then don the dry suit, and help is more likely going to be needed getting into the dry suit and zipped up.

Ideally you would have both. If there was time to get into the dry suit, that would be the ticket. But if there wasn’t, then you’d have the immersion suit as back up. If you had to carry just one, after what we’ve seen, it is a close call. Although we are usually opinionated on subjects marine, in this case we just don’t have the experience to make a definite call. But for most, we’d say an immersion suit was a better compromise because of its ease of use, and substantially lower cost.

On the other hand, if you are going to have a dry suit aboard for maintenance, then carrying an immersion suit as well is a harder decision. More space, more maintenance, more gear to be familiar with…we’re just not sure what to say. For our purposes Dug thought a dry suit combined with a life jacket made sense.

One of the issues we have thought about in the past was how hard it could be to breath if the waves are breaking and spray is flying. We asked Dug about this and the answer was "not easy." It depends on sea state, wind, and how you are floating. But in heavy weather unintentional ingestion of salt water as you are trying to breath can be a real problem. The British have developed a spray hood to be worn in the water to help with this situation. We’ll do some investigating on this and report our findings.

It is hard to imagine this is just a small part of what we picked up during the AMSEA survival training course. Here’s a recap of a few of the points which stood out to us:

  • If you want maximum survivability potential, carry an immersion suit, or some other form of protection. The colder the climate, the more critical this becomes.
  • Get formal training with your gear, and practice periodically getting into it.
  • Take care in maintaining your survival suit and in particular the zipper.
  • Have an abandon ship plan and conduct drills, even if it is just two of you aboard

For abandoning ship:

  • Get out a May Day message with vessel coordinates (lat/lon), name of vessel, and number of crew. Trigger GMDSS alarms on VHF and SSB if so equipped.
  • Assuming you are shorthanded, do not engage in lengthy radio dialog. After the message is out, complete abandon ship preparations.
  • Get EPIRB ready to go and trigger.
  • Bring abandon ship gear into position.
  • Get into warm, preferably polyester pile, clothing and don immersion suits.
  • Launch life raft and dinghies.
  • Bring extra supplies that may help sustain you. In particular, water.
  • Except in case of fire, always step up into the life raft. You are usually better off staying with the big boat as it is easier for rescuers to spot and you will be more comfortable.

We want to be close by, reiterating what we said at the beginning. Knowing how to get into one of these suits quickly, probably on a heaving deck, maybe with fire crackling around you or breaking seas pummeling the boat, can be the difference between living and dying. Get formal instruction in the use of this gear, and then practice periodically.

Posted by Steve Dashew  (July 11, 2007)

4 Responses to “Survival Training Part 5: Immersion Suits”

  1. dineshwar singh Says:

    what is external flotation bladder on immersion suit and when it should be inflated?
    a: before you enter the water
    b: after you enter the water
    c: after 1 hr in the water
    d: after you notice that your suit is loosing buoyancy

  2. Steve Dashew Says:

    When we did our training we had lots of buoyancy without the flotation pillow. Our recollection is that it was inflated in the water.

  3. Says:

    How long in the Bay of Fundi, near NewFoundland at this time of year could you survive in a survival suit?

  4. Steve Dashew Says:

    In the water survival with an immersion suit depends on whether or not you are dry when you suit up, the water temperature, and your will to live. There are reports of fishermen surviving for 18-24 hours in Alaska.