Performance Boat Candy works great. All of there products work really well:)
http://www.performanceboatcandy.com/

Gentlemen,
I make a products called Surf Away Spray Detailer. It removes fresh water spots, and the day's fun witha spray on and wipe off application.
It contains only polymers so it doesn't streak or smear on fiber glass, paint, windscreens and bright work. The polymers leave a water repellent coating that reduces future water spotting and enhances gloss.

Feel free to look at my website www.hulaboatcare.com