A lot of boaters think about hauling their boat as a time to simply clean and paint the bottom before the start of the season. We used to think that way, as well, but it is so much more.
At the end of your season, I strongly recommend that you hire a diver to inspect below your waterline. Have the diver check your prop and shaft for any damage (nicks or twists), identify any growing plant life and barnacles, look for paint peeling and blisters, inspect through-hulls, logs and struts, and check zincs and replace them as needed. I have hired divers who will bring an underwater camera for before and after pictures.
Before hiring a diver, inspect the inside of your hull. Make sure all through-hulls look good. If you have water in the bilges, try and figure out from where it is coming. A good technique is to thoroughly dry the bilges, sprinkle powder around possible water sources and inspect the areas later for streaks through the powder. Colored powders can often be found at craft stores, to help your forensic efforts. Some issues could dictate that you go straight to the boatyard and forget hiring the diver.
Divers can do a lot of work you might otherwise have done at haulout, including removing props for fixing, tuning and polishing. Replace the zincs if it is going to be too long before haulout. I like to be at the boat while the diver is in the water, so he can use his camera to show me any issues and I can make a decision while he is in the water. Or, the diver can email pictures. Finally, if you hauled out your boat at the end of the season, the diver can also clean the bottom just before you start your next season.
Once you have the information from the diver and your inspections done inside, you can better plan the haulout. If it turns out that all you need is a cleaning and bottom paint, that can be done in a day. Fixing blisters can take a few months. Most everything else can be measured in days or weeks.
If your boat may be out of the water for more than a day or two, consider the yard’s charge for lay days and its willingness and ability to help with any services you may do yourself. For major repairs, it is often good to use a boatyard that allows you to hire those services directly, because anything that is hired by the yard will have an additional percentage. Knowing the extent of the work to be done before your next season will help you time things so you won’t have your boat sitting on the hard when you want to be cruising.
One thing often overlooked at the boatyard is to check the bottom with a moisture meter. Check carefully around through-hulls, logs and struts. Do this every haulout, as it may take a couple of years to detect changes requiring peeling the gelcoat and resurfacing. Also, if you can, wax the hull at the boatyard; it is a lot easier than lying on the dock.