Bottom paint removal?

[CHANCE1234]

I have at least 3 different colors on the bottom. I'm sure it has never been removed in its 40 years so lucky me... Like I said there are 3 colors and for sure multiple coats of the black. The below picture is one hour worth of work with a scrapper on the easiest most vertical portion of the boat. The rest will have to be done on my back. Unless someone has a better idea besides blasting (don't have a ton of money budgeted for this but I do have plenty of time over the northeast winter). I assume pressure washing won't get it done? My next attempt will be with an orbital sander and the coarsest grit paper I can find. Any other ideas?