I used to hand sand, some power sand in some spots. Gave it up years ago. Got tired of ingesting it.
As others mentioned, power wash, using ablative paint makes a difference. I also bought at a paint or hardware store years ago a swivel head that mounts on a pole that takes rectangular cut sandpaper. Was a big help reaching in.
I have enough ablative use where a paint scraper, some sanding near the water line, power washing is all it gets for preparation.