Are there no boat clubs in your area?
As a club member I am allowed to use the club's slipway for a week every second year free of charge and can also use the club power wash without charge.
The only expense is for bitumen, brushes, rollers and anodes if needed.
I used the slipway last June and did the work as follows:-
Day 1 Moved boat on to slipway and power washed immediately, later that day fitted 2 new anodes and applied first coat of bitumen.
Day 2 Applied 2nd coat of bitumen and started to touch up paintwork.
Day 3 Applied 3rd coat of bitumen and continued to touch up paintwork.
Rest of week - touching up paintwork.
I must point out that the first week of June last year was a scorcher and helped with the drying.
Cost of work - less than £100
Have a look on the AWCC website for a list of boat clubs in your area.
Steve