| After their raft flips in the cold waters of the | | | | Survival time in a drysuit is lengthy, even in very |
| South Fork Boise River, Russ Campbell and Amy | | | | cold water. Coated nylon drysuits can be |
| Gerver cling to the upside down raft through a | | | | sweatboxes in air temperatures above 60°F, |
| long rapid. They are experienced rafters and are | | | | but Goretex and some other water-proof |
| dressed in "Farmer John" neoprene wetsuits, | | | | breathable drysuits may be worn with relative |
| neoprene booties, neoprene gloves, waterproof | | | | comfort in air temperatures up to 90°F. |
| paddle jackets, life jackets, and helmets. | | | | Drysuits have become standard garb for most |
| However, within only a few minutes in the very | | | | experienced cold-water boaters. |
| cold water, they are unable to respond to | | | | DRYSUIT PLUSES: They really are waterproof! |
| instructions, or swim to shore. They die soon | | | | Except for your head, there is no entry shock of |
| thereafter of hypothermia or drowning. Their | | | | cold water contacting your body. Trapped air |
| unfortunate deaths have been a catalyst for my | | | | inside adds considerably to swimmer buoyancy. |
| research into water temperature ranges, survival | | | | (NOTE! Kayakers must immerse themselves in |
| time in cold water, and protective clothing for cold | | | | water and remove most trapped air from dry |
| water boating. | | | | suits, "burp the suit," to retain neutral buoyancy |
| Water temperatures March - July, in the Northern | | | | needed to Eskimo roll). Dry suits also maintain |
| Rockies. These temperatures are a summary of | | | | body warmth when paddlers/rowers are |
| measurements taken on Fish Creek, a tributary | | | | experiencing cold air temperatures, shade, wind, |
| of Idaho's Lochsa River, and at the Sawtooth Fish | | | | rain, and wave splash |
| Hatchery near Stanley on Idaho's Salmon River. | | | | DRYSUIT MINUSES: by nature of their technical |
| * Month / Fish Cr. Temp / Salmon R. Temp | | | | construction, drysuits are expensive: prices range |
| * March / 35-39°F / 33-43°F | | | | from $360.00 to $1,000.00. Some new users find |
| * April / 39-43°F / 36-47°F | | | | the latex gaskets, especially the neck gasket |
| * May / 43-46°F / 41-52°F | | | | uncomfortable. The neck gaskets can be |
| * June / 46-54°F / 45-58°F | | | | pre-stretched over bowls or smooth helmets, or |
| * July / 54-66°F / 51-59°F | | | | cut to fit larger: but most users don't mind the |
| Fish Cr. measurements, courtesy of Idaho Dept | | | | snug gasket fit. Drysuits can be sweaty in |
| of Fish & Game, Alan Byrne 1998 ( My | | | | warmer temperatures, but Goretex suits do have |
| Lochsa River pundits tell me Fish Cr. is one of | | | | a very wide comfort range. The suits are |
| Lochsa River's warmer tributaries. I use it because | | | | somewhat time consuming to put on and take |
| of good temperature data from Steelhead study). | | | | off, and bathroom stops do require partial suit |
| Salmon River measurements, mean temps | | | | removal, unless extra option zippers are installed. |
| 1999-2000, courtesy of Sawtooth Fish Hatchery, | | | | Drysuit gaskets are natural latex rubber, should |
| Idaho Dept of Fish & Game | | | | be regularly treated with 303 Protectant, and |
| Water temperature is influenced by air | | | | depending on use, will probably need to be |
| temperature, percent of snow-pack melting, | | | | replaced every two to five years. Drysuit fabric |
| groundwater temps, and solar warming. Expect | | | | should also be periodically treated with durable |
| colder water at higher elevations and at further | | | | water repellency treatments (DWR) to prevent |
| north latitudes. Also, dam control water may be | | | | heat loss from the fabric "wetting out." (Note on |
| significantly colder in the months of June-August. | | | | pricing: drysuits are generally less expensive than |
| This is a major factor on South Fork Boise River, | | | | funerals.) |
| South Fork Payette below Deadwood River, and | | | | WETSUITS were originally made from neoprene, |
| in the Grand Canyon below Lake Powell, where | | | | but now come in a wider range of stretchy |
| river temperatures remain in the 40°F range | | | | fabrics. Suits range from one piece full coverage |
| at mid-summer. | | | | "STEAMERS" that are the warmest, to vests and |
| Cold Water Temperature Survival Time | | | | shorts. Thickness of material also varies, but 1mm |
| Water conducts heat 22 times faster than air, | | | | to 3mm thickness is available for river users, |
| quickly reducing body temperature. | | | | because thicker neoprene limits movement. Per |
| Water temp °F Time before Exhaustion or | | | | the name, water enters the suits and is warmed |
| Unconsciousness | | | | by body heat. Fit should be snug to prevent |
| - 32.5° - Under 15 minutes | | | | circulation of cold water. Boaters can combine |
| - 32.5-40° - 15-30 minutes | | | | wetsuits with waterproof paddle tops to increase |
| - 40-50° - 30-60 minutes | | | | warmth when out of the water. |
| - 50-60° - 1-2 hours | | | | WETSUIT PLUSES Wetsuits are much less |
| - 60-70° - 2-7 hours | | | | expensive than drysuits, ranging from $80.00 to |
| - 70-80° - 3-12 hours | | | | $195.00. Other than occasional washing, there is |
| - Over 80° - Indefinite | | | | little maintenance. The thicker suits do improve |
| This table is widely available on line. Based on | | | | buoyancy and pad against impacts. Wetsuits help |
| Alexander Report | | | | protect swimmers from hypothermia in all but the |
| Survival time in cold water is also affected by: | | | | coldest water. |
| body temperature, glycogen (blood sugar) level, | | | | WETSUIT MINUSES The suits lack breathability |
| percentage of body fat, physical conditioning, | | | | and can be uncomfortable in hot weather. Full |
| mental attitude, exertion, and most | | | | wetsuits can be difficult to put on and take off. |
| importantly------- protective clothing worn. | | | | Swimmers have died of hypothermia in relatively |
| Protective Clothing & Hypothermia | | | | short times in cold water in "Farmer John" |
| Protective clothing is important in the boat, as well | | | | wetsuits that leave the user's arms unprotected. |
| as in the water. Kayakers will experience direct | | | | The deaths of wetsuit wearers Amy Gerver and |
| conductive cooling from cold water through the | | | | Russ Campbell, is a sad lesson that wet suits do |
| bottom of their boat. Both kayakers and rafters | | | | not maintain body warmth for survival in very |
| will cool down when out of direct sunlight. Also | | | | active cold water. I have checked float time |
| wind, rain, and wave splash will cool down boaters | | | | through the rapid they died in-----as less than 5 |
| rapidly. A cold boater will react more slowly and is | | | | minutes. I believe they were already suffering Mild |
| at higher risk of accident. | | | | Hypothermia before the accident. That is the |
| The very best Cold Water Survival advice is: Stay | | | | most likely explanation for why they became |
| Warm while out of the water!! If shivering starts: | | | | incapacitated so quickly. |
| RE-WARM by stopping! Add more dry clothing, | | | | People get hypothermia in wetsuits most quickly |
| eat high sugar foods, and drink hot non-alcoholic | | | | when the suits drain and refill: thus cooling body |
| fluids. Some dry-land exercise may help | | | | core temperatures. This can happen repeatedly |
| re-warming. Alcohol should not be consumed by | | | | when swimmers are clinging to the side of a raft |
| cold boaters: it dilates the capillaries and causes | | | | that is going up and down through a rapid. It also |
| further cooling of the skin. | | | | happens when a boater is constantly getting |
| As humans cool down: available glycogen (blood | | | | slapped with waves while paddling. There can be a |
| sugar) is depleted and core temperature drops | | | | considerable loss of body heat from wind and |
| from the normal 98.6 F. to the mid 90 degree | | | | water related evaporative cooling of a wet |
| range. A boater who is shivering, may show signs | | | | wetsuit. Some new wetsuit materials are designed |
| of weakness and fatigue and will probably be less | | | | to reduce evaporative cooling. |
| coordinated (symptoms of Mild Hypothermia). | | | | Insulated head, feet, and hand coverings will keep |
| They can make really stupid decisions, and may | | | | paddlers warmer both in and out of cold water. |
| be irritable or apathetic. They are much more | | | | Recommended Clothing for Water Temperature |
| likely to have an accident and be forced to swim. | | | | Water Temperature Recommended Clothing |
| Since water is much denser than air: it conducts | | | | Over 80° F Minimal. |
| heat from the body approximately 22 times | | | | - 60-79° F - Light wetsuit vests, paddle tops, |
| faster than air. When boaters with Mild | | | | Kayakers-drytop 60-69°F. |
| Hypothermia enter water below 60 degrees F: | | | | - 50-59° F - 3mm body, 2mm arms/legs Full |
| remaining body heat is quickly lost. They will cool | | | | or "Steamer" wetsuit, or drysuit with light |
| down very quickly into Moderate or Severe | | | | insulating layer, Kayakers add drytop with |
| Hypothermia, because their body temperature is | | | | insulation. |
| already lowered and their glycogen stores are | | | | - 40-49° F - Drysuit-light to midweight |
| depleted. Within a few minutes in water below | | | | insulation inside. 5mm "steamer" wetsuit (availability |
| 60ï,°F ------ hands will lose dexterity; | | | | limited). Kayakers need heavier insulation: drysuits |
| then the mind fogs and swimmers may be unable | | | | with head, hand and feet insulation. |
| to save themselves. | | | | - Below 40° F - Drysuit with midweight or |
| Warmer boaters have a longer survival window in | | | | heavier insulation, head, hand, and feet insulation. |
| cold water because: higher body temperatures | | | | Or just say no! |
| and higher glycogen levels allow a longer period of | | | | The U.S. Coast Guard, which has Gore-tex |
| physical and mental agility. | | | | drysuits available for its small craft crews, |
| Clothing for Cold-Water Survival. | | | | mandates those crews wear drysuits when water |
| There is some agreement among cold-water | | | | temperature is below 50°F. |
| survival experts as to what protective clothing | | | | In Closing, I must agree no boaters expect to be |
| should be worn to survive in water below | | | | swimming for more than a few minutes before |
| 60°F. Most experienced boaters have a good | | | | they are rescued or make it to shore. |
| idea about what water temperatures may be, | | | | Unfortunately, long swims take place. My |
| and what clothing should be worn for a particular | | | | experience with this was: chasing my sister-in-law |
| situation. Unfortunately a lot of beginning and | | | | down the very cold and flood swollen Bruneau |
| intermediate boaters don't have a clue about | | | | River (3,300C.F.S.), after her raft flipped right in |
| water temperature, or correct clothing. In many | | | | front of me. She was in the water, in a drysuit, |
| cases, these are the people most likely to swim | | | | for about 15 minutes in constant Class IV rapids, |
| and least likely to have the right clothing for cold | | | | clinging to the flipped raft. When rescued she was |
| conditions. | | | | very tired and slightly cold, but alive. |
| The major choices are DRYSUITS and WET | | | | Further Suggestions: |
| SUITS. | | | | - Read a book on river rescue -Les Bechdel's |
| DRYSUITS are designed to keep you dry. They | | | | "River Rescue" is the classic. |
| are generally constructed of waterproof nylon | | | | - Take a swift-water rescue course. |
| fabric, with a waterproof entry zipper. Neck and | | | | - Take a comprehensive first aid course with a |
| hand openings are sealed with waterproof latex | | | | CPR component. |
| gaskets. Feet may be encased in the suit or stick | | | | - Boat with people who have taken the above |
| out through latex ankle gaskets. Drysuits are | | | | suggestions. |
| worn with a light insulating layer inside for warmer | | | | Dress smart to stay warm, both in and out of |
| water, heavier insulating layers for colder water. | | | | the water. A cold shivering boater is going to cool |
| Insulation worn under dry suits should be synthetic | | | | down and become incapable of self-rescue much |
| insulations or wool. Cotton or down will hold water | | | | more quickly than a warm boater, when plunged |
| and lose all insulating value when wet. | | | | into cold water. |