The water doesn't care that it's seventy degrees out

Quick answer: Dress for the water temperature, not the air. Wear your life jacket, don't stow it. Practice a wet exit and re-entry in the gear you'll actually wear, close to shore, with a partner watching.

The first minute is the dangerous one

Picture a still April afternoon. Air temperature, 70. Sun on the lake. You're in a T-shirt and shorts, and the water is 48 degrees.

You tip over. It happens to everybody eventually.

The cold hits your skin and your body gasps, hard and involuntary. You may breathe in water. Your breathing runs fast and ragged for a minute or two. This is cold shock, and it's the part that drowns strong swimmers who never get cold enough for hypothermia to matter.

Cold-water researchers describe it with the "1-10-1" idea. You get about one minute to get your breathing under control. You have roughly ten minutes of useful muscle control in the arms and hands before they quit on you. And it can take about an hour before hypothermia costs you consciousness. Those numbers shift with water temperature, body size and clothing, but the order never changes. The first minute comes first.

That's why the life jacket matters most. It has to already be on you when you hit the water.

Wear the jacket. All of it.

Year after year, Coast Guard accident reports show that most boating drowning victims weren't wearing a life jacket. Federal rules require a wearable one aboard for every person. The one under the bungee on your deck doesn't count if you're in the water and the boat is drifting away from you.

Some practical points:

• Fit it standing, then test it. Cinch it down, lift the shoulder straps hard, and see if it rides up over your chin. If it does, it's too loose or the wrong size.
• Pick one made for paddling. Short-torso, high-back designs sit above a kayak seat back and don't bunch. Brands like NRS, Kokatat and Stohlquist build them. Try several on in the boat if you can.
• Think hard before going inflatable. A belt-pack inflatable is comfortable and fine on warm flatwater. In cold water the first minute is chaos. If it needs to be pulled, armed or inflated by mouth, you may not manage it. A foam jacket works with no action from you.
• Buy the right size for kids and make it a rule. Kids wear theirs from the moment their feet leave the dock, with no negotiation. You set the example first.

Dress for the swim you hope you won't take

Many paddling instructors use a rough rule of thumb. Add the air temperature and the water temperature. If the total is under about 120 degrees, dress for immersion. If it's under about 100, don't paddle without serious immersion gear. It's not a law of physics. It keeps you honest on days when the sun is lying to you.

What "dressed for immersion" means:

• Wetsuit. A 3 mm farmer john with a paddling jacket is the entry point for a lot of people. It's cheaper and forgiving, and it still keeps a thin layer of warmed water against your skin. The annoying part is that you're a little warm on the paddle in and cold on the break.
• Drysuit. The better answer for sustained cold paddling. Latex gaskets at the neck and wrists keep the water out, and insulation goes underneath. It costs real money and needs care. The gaskets perish and the zipper needs lubricating. Ask your dealer about gasket replacement before you buy.
• Base layers. Wool or synthetic only. Cotton soaks up water and holds it against you.
• Hands, feet and head. Neoprene gloves or pogies, booties, and a neoprene hat or hood. Your hands decide whether you can pull yourself back onto the boat or not.

Wearing the gear isn't enough. A drysuit with the relief zipper left half open fills like a bucket. Check yours before you launch.

Self-rescue is a skill, not a plan

Reading about re-entry doesn't teach it. Doing it in cold water, in heavy gear, with a wet deck, does.

Know these before you need them:

1. The wet exit. Lean forward, pull the spray skirt grab loop, and push out. Do it flat-water, with a partner nearby, until you can do it without thinking.
2. Stay with the boat. A boat floats and is much easier to spot than a head. Hold the paddle and the boat if you can.
3. Paddle float re-entry. For sea kayaks, this is the common self-rescue. A float on the blade makes an outrigger, and you pull up across the back deck. It works, and it's harder than the videos make it look.
4. Cowboy scramble on a sit-on-top. Flip it upright, kick, pull and straddle the boat.
5. Assisted rescue. If you paddle with others, practice the T-rescue so the boat is drained before you climb in.
6. Swim or stay. If shore is under a few hundred feet and you're in the water with no boat, swimming may be the best option. If it isn't, climb onto the upturned hull and get as much of your body out of the water as you can.

Practice in spring or fall, close to shore, in your actual gear. Bring a partner and a thermos. You'll learn more in one cold session than in ten warm ones.

Carry the means to call for help

A whistle on your jacket zipper. A waterproof VHF radio or a personal locator beacon if you paddle open water. A phone in a dry bag you can reach, in case the water is deep and the boat isn't. Tell someone where you're going and when you'll be back. The ten items on the old essentials list still apply on the water, and you need a change of dry clothes in a dry bag.

Check the forecast too. Wind on open water builds faster than most people expect. The weather that kills hikers covers reading it in time, and the same habits keep a paddler off a lake at the wrong hour.

After the swim

Get out of the wind. Strip the wet layers, get dry insulation on and something warm and sweet in you. Get off the ground, or off the cold rock, because the ground steals your heat first. Shivering that stops while you still feel awful is a warning, not a recovery. If someone is confused, clumsy or slurring, call for help.

Hold the line

If you're leading a group, you'll feel pressure to go anyway. Everyone drove two hours, the sun is out, and nobody wants to be the guy who calls it off. Be that guy. A friend who's mad at you for a day beats a friend you pull from the water.

And leave the launch better than you found it. Pack out the line, the can and the cigarette butts, and shake the sand out of your drysuit before it goes in the truck.

The lake is beautiful in April. It's also 48 degrees. Plan for both.