What to charge per foot for boat washing and waxing?

I started a yacht maid cleaning service for 20.00 an hour to clean the interior of the cabin.But someone ask me if i washed boats so we did a 44ft sailboat yesterday.It was so dirty cleaned 5 hours i clean the inside detail while my husband and a friend did the outside.We made 275.00 for this job.The products cost me 100.00 and had to buy my helper.We came out making hardly anything.This was a learning process.I want to charge 15.00 a foot plus 20.00 an hour for detailing the inside.Just want to know if this is a good price.Thank you.Bye the way the sailboat turn out beautiful.