Here are some do's & don'ts, and some great products when it comes to keeping your boat looking "ship shape." I've owned quite a few boats over the years and done a lot of damage to the gel coat on some and have found some really great products to keep the boat looking it's best. The picture below of my 2003 Mainship was taken in 2014. She looks better in most respects than when I took posession in '03.
Never use clorinated or abrasive cleaners on gel coat. I don't care how mild they claim to be. They will make your boat sparkle for a very short time before your gel coat turns to a pitted and dull, dead finish. For real tough stains and black streaking, use "Spray Nine." It is economical, available at Home Depot, and it will remove just about anything. Use it for tough cleaning only before waxing as it will remove any wax as well. Never, ever use Soft Scrubs or those types of abrasive, clorinated cleaners, and never use bleach. Never use scouring pads on the gelcoat, trim, or stainless steel fittings and rails.
My favorite boat wash is Woody Ultra Pine Boat Soap. Woody’s non-alkaline wash is specifically formulated NOT TO STRIP WAX like other boat soaps. It leaves a shiny and clean wax finish -water beads off beautifully! WOODY WAX ULTRA PINE WASH –N-WAX BOAT SOAP contains antibacterial additives that kill mold spores and odors on contact. Fresh and clean smelling, this product is safe for all surfaces and is safe for the environment. The 32 oz bottle will last you all season.
For cleaning off last year's black streaks, diesel soot fish blood etc..., nothing works better than Spray Nine and is still gentle to the gelcoat. You will also find it handy in the shower and head. In the bilge it kills mildew and degreases any thing needing heavy cleaning. No clorine, ammonia, or abrasives. It is the only cleaner besides dish washing liquid, I keep on the boat. It does everything! Below is from their website.
The most versatile tool in your cleaning arsenal!
Spray Nine’s professional-strength cleaning power has been trusted by millions of professionals and consumers for over 50 years. Spray Nine works hard to remove all types of dirt, grease, grime and stains.
One Product, NINE Uses!
3. Disinfects against viruses in 30 seconds
4. Disinfect against bacteria in 45 seconds
5. Sanitizes in 10 seconds
6. Kills fungus in 3 minutes
8. Controls mold & mildew
9. Removes stains
Kills viruses and bacteria including:
Pandemic 2009 H1N1 Influenza A (Swine Flu), Influenza A2 Virus, Salmonella Choleraesuis, Escherichia coli (E.coli), Hepatitis B & C Viruses, Norwalk Virus, Staphylococcus aureus – MRSA (HA & CA) and more!
Even if you don't have any scuffs or abrasions, the sun will take it's toll on your gel coat. By far the best polishing compound I have run across to remove light to moderate oxidation and light scratches is 3M Marine Finesse-it II. Using an 8-9 inch buffer with wool buffing pads, and the proper technique, you can get your gel coat back to showroom condition in little effort. The secret is applying the compound sparingly to the surface and working the buff from dry area already buffed into and back out of the wet coumpound just a little at a time and allowing the wheel to work the compound to an almost dry condition before moving back into the fresh wet area again. Everytime I use this stuff, I am just amazed!
Another favorite product line is Meguiars. The Flagship Premium Marine Wax is the best wax I have found yet. Nothing goes on so easily and last so long as this wax. Most waxes will streak when apllied in direct sunlight, and then are a bear to hand buff off. Flagship Premium Marine Wax can be applied is direct sunlight, is easy to wipe off and need only be done once a season, here in the Northeast. Fantastic product. Meguiars makes a full line of marine cleaners and waxes and I have only tried a few. After years of trying other premium products like 3M and Collinite, etc..., I would never go back. It's a higher cost product than most, but you get what you pay for.