More comments and thoughts.
Sailmaker is a crook, and you should insist that he fix what he broke. If he felt he didn't want to charge you for picking off the old UV strip, he should have told you and you could have done it. It's a really easy job with a seam ripper, and his excuse is bogus and just the sign of a substandard sailmaker. I assume you paid him. We encountered such a poor sailmaker, and it takes a long time to get the bad taste out of one's mouth after such an experience.
Mast steps. Whatever you use to attach them to your aluminum mast, be sure to paint them, or the aluminum where it comes in contact with the rivet, with an isolating paint. Monel is only slightly less corrosive against aluminum than stainless steel, so you will have galvanic corrosion if you don't isolate the two metals. http://en.wikipedia.org/wiki/Galvanic_series
Richard will provide you with better information regarding electrolysis, but I believe that you should have, or should install, a bonding system for your boat. Also, as Richard suggests, hang some sacrificial zincs (most marinas sell them as chunks of zinc cast in the shape of a fish) in the water, connected to the raw aluminum of your hull.
Do you have a reverse polarity detector for your electrical system when attached to shore power? We had a friend who stayed tied to the dock in American Samoa for two years with no clue that the power on the dock was wired wrong. The reverse polarity rotted out his engine oil pan, and his propellor fell off! OMG!