Bottom paint is a type of hull paint that repels growth from occuring on the bottom of the boat. This hull paint is generally applied from just above the waterline of the boat on the hull. Bottom paint should be used if you want to keep marine growth off the bottom of your boat. Fresh water has the least amount of potential growth on your boats' hull. If you hull is in salt water for over a week, you will need to have a good bottom paint on the bottom of your boat. The warmer the water, the more potential for growth.
Aluminum boats require special hull paints that are compatible with aluminum. It is important to use the correct primer or hull paint that can be used on aluminum and protect the aluminum from corrosion.
Also none as a non-slip paint. This hull paint is used above the waterline in areas where you want to create a slip free surface for walking. Great around steps and other areas where you could slip on a boat.
Find the right hull paint that will give you the shine, UV protection, but still give the durability for below the waterline.
Gelcoat, also known as gel-coat, gel coat, and gel coat paint is what has been applied to the outside surface of all fiberglass boats. Gelcoat is really not a paint and is much thicker that other hull paints. It provides the highest protection for your fiberglass boat, but is generally more time consuming and difficult to apply to your boat.