Deck misery

I've decided to nix the plan of sanding the chipping deck paint at anchor. First of all, it generates enormous amounts of dust, which ends up in the water, which drives me crazy. Second, it's completely unclear how far to go: the original gelcoat is light blue, the coat over that was smurf blue and thin, and the white coat over that is white, super thick and chipping. In some parts, as soon as you touch the sandpaper onto the deck, you're down to gelcoat. In other parts the white is well-adhered and you're faced with the dilemma of whether to just feather the edges or keep going to get it all down to one of the blues. To boot, during the time of day when it's not blowing, i.e. in the morning, the motion of the boat is likely to make me queasy in half an hour.
It's either going to take a haul and a proper power-sanding, or I'll have to put up with the deck situation for yet another summer :-(