It's as simple as 1, 2, 3, 4. But there's a knack and order to getting it right.
1. Set The Stage:
Before you even think about backing down the ramp, take 10 minutes in the staging area to load all the gear into the boat, attach lines to the bow and to the stern cleat, check that the plug is in, remove the rear tie-downs, put the key in the ignition, and unplug the trailer lights.
If you have surge brakes, unplugging the trailer lights will also de-energize the circuit that prevents your trailer brakes from locking up when you reverse. You'll need to use the manual brake lockout to prevent this. Also, go ahead and lower the motor or outdrive if it won't bottom out on the way down the ramp.
2. Back It Up:
Back down the ramp till the stern of the boat floats. If you can't tell when the stern is floating, have a crewmember positioned on the dock beside the ramp to signal when to stop. Put the vehicle in park, and engage the parking brake, but leave it running. If you have trouble backing straight, try resting your hand at the bottom of the steering wheel. That way, whichever direction you move your hand, the trailer will turn in that direction.
3. Unhook The Bow:
Depending on how steep the ramp is, or how athletic you're feeling, you may be able to scramble along the bumper or step up onto the tongue of the trailer and not get your feet wet. But it's advisable to wear water-friendly shoes, or rubber boots, in case you have to wade in to reach the bow eye and winch handle. Many boat ramps are slick with algae during summer months, so don't be surprised if your feet start to slide.
Tip: If you use the same ramp frequently, mark the waterline on your fender or guides at the point where the boat floats free. That way you can always back down the correct distance.
Once you can reach the bow eye and handle, unhook the safety chain, and back the winch off to get enough slack to release the bow strap as well. Pass the line on the bow cleat to a crewmember on the dock, and push the bow of the boat up and off the trailer. If you've backed down far enough, this should be relatively easy, and the boat should float gently off.
4. Nice Going! (Now, Keep It Moving):
While you head back to the driver's seat to park the tow vehicle, make sure the crew is walking the boat down to the far end of the dock to free up the ramp for the next boater.