After a great day on the water, now is not the time to mess up.
1. Drop And Go
Deposit the driver of the tow vehicle at the end of the dock to go retrieve the truck and trailer. Idle out away from the ramp or, if you won't be impeding others, pull alongside at the far end of the dock. Meanwhile, attach one line to a bow cleat and one to the stern; the latter is especially important if there is wind or current.
When you see your towing rig pulling into position to back down the ramp, get everyone off the boat and onto the dock except the operator. Leave the gear aboard; you'll unload it later. Have crewmembers on the dock hold the lines to keep the boat in position just beyond the reach of the trailer. Signal the vehicle driver when the trailer has backed far enough down the ramp for loading. The driver should put the vehicle in park, engage the parking brake, and leave the engine running.
3. Drag Or Drive
Many boats can be floated most of the way onto the trailer without much effort. But if your boat is large or susceptible to being pushed about by crosswinds, you may have more control if you slowly drive it onto the trailer. Do not apply the throttle to "power load," as this practice washes away the material under the end of the ramp, which can lead to its deterioration.
4. Winch It On
At this point, either you or the driver must get into position on the trailer tongue to attach the winch strap or cable to the bow eye of the boat, then crank the boat fully onto the trailer. When the bow is snug against the winch post, attach the safety chain.
5. Pull Up Slowly
Raise the outboard or sterndrive if necessary, and have the driver pull slowly up the ramp. Get off the boat and follow the tow vehicle to the loading zone.
6. Unload and Drain
Pull the plug and drain any livewells and bait containers. To minimize the risk of transferring invasive species, all water in the boat must end up back in the same body of water from which it came. Pull all plugs first, after leaving the water, so there's plenty of time for the boat to drain while you load your gear into the tow vehicle, attach transom tie-downs, lower any bimini or antennas, and do everything else that needs to happen before the boat can hit the highway. Don't forget to plug in the trailer lights!