Re: Bottom paint
Does your boat live in the water year round or does it spend more than a few days at a time out of the water?
The reason I ask is that most bottom paints go dead if left out of the water others don't.
Tell us more about how you use the boat.
"How long does it usually last ..."
Depends on the paint, where you are, and how you use the boat.
"Would I have to sand it?"
Yes,
You also need to know what kind of paint you'll be painting over. Different types may not play well together. The paint manufactures can help you with compatibility questions. What type of paint did you use last year?