The question of whether you should power onto the trailer or crank the boat up (assuming your trailer design accommodates either or) is likely to have a different answer depending on who you ask. Specifically, whether you ask a boat owner or a marina owner. Boat owners know that powering on requires a lot less time and effort. Marina owners, on the other hand, often say that powering on damages the ramp. So, who’s right?
Unfortunately, both. Unless you have a roller trailer, a relatively light boat, and a relatively stout winch, powering on is going to be one heck of a lot faster and easier. But as you do so, the propwash can dig a hole out of the mud and sand behind the ramp. Eventually, if the ramp becomes under-cut it can collapse. This usually isn’t an issue with well-designed ramps, which are long enough that your propwash has lost all its oomph by the time it reaches the end of the concrete. And in some other cases a layer or rocks placed behind the ramp can resolve the issue, at least temporarily. But at some ramps, yes, powering on does take a toll over the years.
Those who side with the cranker-uppers, however, are forgetting one over-riding factor: safety. Most accidents which occur when loading a boat onto a trailer are related to winching. Straps and ropes under the strain of hundreds or thousands of pounds can break, and sling-shot back at you. Eye bolts can snap off, to the same effect. Winches can pop free and send the handle spinning backwards, breaking arms and ribs. The bottom line is that cranking a boat onto a trailer puts your equipment under a lot of strain, which can cause a dangerous situation – while powering on does not. End of argument!