Not only that....
With a pressure washer, I found all my weak pionts in my gelcoat. The pressure washer actually knocked out gelcoat where there was voids underneath.. and believe me there are some of those on all boats.. even more expensive makes. So, I prefer the Joy Soap and bleach method, few tablespoons of Joy and about a 1/4 cup of bleach mixed with about 2 gallons of water, soap up the deck from one end to the other without rinsing, then scrub the entire deck a second time and allow it to sit a few minute before rinsing. When you return to your boat a couple of days later, she will look like a new boat. The bleach keeps killing the mold, mildew and algae while you are at work on your day job to pay for the slip fee. Have joy and a good day.