Launch Day and Haul-Out Checklist for Trailer Boats

Check tire pressure (including the spare), lug nuts and lights. Mercury calls underinflated tires the most common cause of trailer trouble: set them to the pressure on the tire sidewall or the trailer's capacity sticker, which is often much higher than a car tire, and check them carefully after the trailer has sat all winter. Make sure the coupler is latched and pinned, safety chains are crossed under the tongue and hooked, and the trailer plug is connected. Touch the hubs after the first few miles and at stops; one much hotter than the rest needs attention (see our wheel bearing guide).

Pay the launch fee. Load gear from the vehicle into the boat. Put fenders on the side that will face the dock. Attach bow and stern lines. Put the key in the ignition and check that the battery turns the gauges on, but do not crank the engine out of the water. On a personal watercraft, Sea-Doo suggests taking the seat off while you prep so any fuel fumes in the engine compartment can clear before you start it.

Screw or press the drain plug in firmly and tighten it. Then have a second person check it. This is the number-one launch mistake, and it sinks boats at the ramp every season. Some owners hang the plug on the key ring or steering wheel when the boat is stored, so it cannot be forgotten.

Take off the transom tie-down straps and any motor support bracket ("transom saver"). Leave the bow winch strap and safety chain attached for now. Raise the motor or drive enough to clear the ramp.

Life jackets for everyone, a throwable on boats 16 feet and up, fire extinguisher, sound device, and the engine cut-off lanyard. Put a life jacket on the person who will drive the boat off.

Unplug the trailer wiring from the tow vehicle before backing in. This protects the lights and the vehicle's circuit from the cold dunk.

Go slowly and use your mirrors, with a spotter where you can see them. Back down until the boat's stern is deep enough to start floating. Keep the tow vehicle's rear wheels out of the water if you can. Set the parking brake and put the vehicle in park.

Lower the motor or drive into the water. On gasoline boats with an inboard or sterndrive engine compartment, run the blower at least 4 minutes and sniff for fuel before starting. Start the engine once the water intake is submerged and check that water is coming out of the tell-tale (outboards) or exhaust. Never run the engine on the trailer out of the water; the water pump can be ruined in seconds.

Unhook the safety chain and the winch strap from the bow eye. Back the boat off gently, or have a helper walk it off with the lines and move it down the dock, clear of the ramp. Drive the tow vehicle and trailer straight to a parking space. Do not stop at the top of the ramp to rearrange things.

Open the bilge and engine hatches and look for water coming in, especially at the drain plug and any through-hulls. Confirm the bilge pump works. BoatUS recommends checking all through-hulls for leaks right after launch.

Drop off whoever will drive the tow vehicle at the dock so they can fetch it, then wait away from the ramp or at a courtesy dock until the trailer is in the water. Back the trailer in to about the same depth you launched from. Too deep and the boat floats off the bunks crooked; too shallow and it will not slide on.

Line the boat up with the center of the trailer and come on slowly. Many ramps ban "power loading" (using a lot of throttle to drive the boat up), so check the rules. Hook the winch strap to the bow eye, crank until the bow is snug against the bow stop, and attach the safety chain. Turn off the engine and raise the motor or drive.

Pull straight up the ramp and into the staging area before doing anything else. Do not unload or tie down at the bottom of the ramp.

Remove the drain plug and let the bilge drain fully. Drain livewells and bait wells. Pull every bit of weed and mussel off the boat, motor and trailer. Clean, drain and dry is the law in most states, to stop invasive species spreading. Rinse salt off the motor and trailer if you were in salt water.

Attach the transom straps, reinstall the motor support if you use one, and stow loose gear. Close the Bimini top. Plug the trailer lights back in and check brake, turn and tail lights with a helper. Walk around once more before pulling out.