As algae grows it secretes a slime that spreads across the hull. In a fairly short time, a few weeks in the summer, it can cover a boat bottom. The algae inhibits the paints ability to slough for ablative paints and to leech for hard paints. The longer the algae is aloud to grow the thicker & more difficult it is to remove. This is why most dive companies, this one included, try to keep customers on a 90 to 120 day rotation. If the boat can be easily wipe clean with out major stress to the paint (and diver) the algae is kept at bay and the hull paint can go much further between haul outs.

There are many different types of algae the most common fouling types on Texas hulls are:

 Hair algae which creates enormous drag in the water

 Back Algae, which spreads across the hull sealing the paint and it can be extremely difficult to remove if it is allowed to   build up on thin paint

Carpet Algae (This one is a little less common) This type of algae grows mostly in colder seasons, it grows with a such a density that it can be pulled off  in sheets and actually pealed or scraped away.