Even if you have ablative anti-fouling bottom paint on a glass hull you may still have issues with growth on the hull bottom and other surfaces. I have found it really depends on how much I use the boat on plane. If you are going out almost every day and running for 15 minutes or more each way on plane to the fishing grounds, water friction will keep the growth down to nothing or almost nothing. The ablative paint is soft and chalky and water friction will wear it off to expose new poison which prevents growth from getting a hold. I have also found that even if you keep the bottom clean with good paint and frequent use, that other underwater surfaces, such as the stainless trim tabs and plastic pistons, outboard motors (especially the mounts), the little water wheel speed sensor etc. will still get fouled with growth fast and need to be cleaned.
Most think that if you can avoid painting your boat bottom that is best. Once you paint it, you have started down a road that will be a lot of ongoing work and cost to maintain and replace it. It really is a lot of work to prep and repaint a boat bottom Some even think it reduces the value of the boat or at least makes it more difficult to sell, as bottom paint can hide a multiple of sins such as marginally repaired hull damage and unless it has been freshly applied does not look all that good. If I was going to buy a smaller to med. size boat with the intention of only keeping it on a trailer and had a choice between two identical boats, I would buy the one without bottom paint.
My boat requires two different types of bottom paint, one for the glass hull and one for the large Al pod and swim grid. Painting it can be done on our old roller trailer, but it will make your trailer look like crap as it is hard to keep paint off it and off your driveway for that matter. Boats on a roller trailer can be moved on the trailer to paint under the rollers but bunks, not so much, and dragging the boat up on bunks can wear off soft bottom paint like a giant eraser. Depending on the size of the boat you can take it to a shipyard, and they will pull it up, prep. and paint it every few years, but that will cost thousands each time.
If your six month marina stay is going to be a one time only kind of situation, I would be tempted to wax it good, go down and take it for frequent short high speed runs and pull the boat and pressure wash it every few weeks. Other things besides the hull are going to need it anyways. Once you paint it you are essentially committed to long term costs and pain in the butt work, but sometimes if you need it, you really need it. The worst thing you can do for growth on the bottom, is to stick a boat with a planing hull in a marina and not use it. Now a slower speed displacement hull, that is a different matter. They usually stay in the water and almost always need bottom paint.
