As the sponsor of Single Mariners, Alan Gornick takes a lot of people on his ketch who have never sailed before. Some will never sail with him again.

“It was a hot, still day. One of my new crew couldn’t take the heat. He tossed his hat in the water and before I could object he jumped in after it. As soon as he hit the ocean that 30 degree temperature difference slammed him. He had a hard time breathing. We had to rescue him. By the time we got him on board he was suffering from hypothermia,” Gornick said.

Hypothermia occurs when a body’s core temperature starts to drop below 95 degrees. Our internal temperature is controlled by the brain’s hypothalamus. On a searing day more blood is pumped to the skin. The body perspires profusely to produce evaporative cooling. Suddenly drop that hot body into an ocean in the mid-60s and that surface heat immediately dissipates. A body’s temperature can start to drop precipitously.

A body’s first line of defense is shivering and producing goose bumps, uncontrolled muscular activity that generates heat. The body next draws blood from the skin, shunting it to the vital organs, the heart, brain and lungs, which is why those suffering with hypothermia can have skin that looks blue. Left untreated hypothermia can cause death.

Hypothermia is always a danger boating out of Marina del Rey, one reason why if you’re not a superior swimmer, you should always wear a personal flotation device while afloat. Humans lose a lot of heat from their heads and PFDs keep people further out of the water while preserving energy for a rescue.

To treat for hypothermia, raise the victim’s temperature gradually. Get him out of any wet clothing and wrap him in a warm, dry blanket or sleeping bag. Don’t feed the victim hot drinks, but warm liquids. If a shower is available, start with lukewarm water then turn up the heat.

Skipper Rick BeauChemin offers this advice for emergencies: “Don’t panic. Stay calm, think through what you have to do, then do it.”

Here’s another all too common boating problem: carbon monoxide poisoning. Boats are built to be water tight. Unfortunately, that design can also provide areas where CO builds up, such as around a stove, engine or generator. Carbon monoxide is a product of incomplete combustion. It’s odorless and invisible. CO poisons by binding with hemoglobin, replacing the oxygen molecule in the blood. Carbon monoxide poisoning can be reversed, but if left untreated can be fatal.

Carbon monoxide can cause dizziness, nausea and fatigue. In its early symptoms, it resembles seasickness or the flu. Unfortunately it can also cause impaired judgment so if you notice that your first mate is stubbornly insisting on wrestling with a difficult meal in the galley while complaining of being queasy, turn off the stove, open the hatches, flood the place with oxygen and get your mate on deck.

The hazards of boating are part of the sport, but knowing what to do when facing a problem not only adds to boating safety, but enjoyment.