If you are like many boat owners, you took your boat out of the water during the winter months. Sometimes storage fees are less than moorage fees and a boat can usually be better protected from winter weather "on the hard"than if it is left in the water. If your boat is left in the water many but not all of the steps below will be applicable. Boats left in the water may also need to have the hull inspected and perhaps cleaned of unwanted hitchhikers and algae which will require some diving under the boat unless it is hauled out.
The first steps is usually unwrapping the boat. Many boats are shrink wrapped for the winter. Others may simply be covered with a tarp. In either case the first step in getting them ready to use it to uncover them Once the covering is removed inspect the surface for any damage or moisture that may have gotten through the covering. Boats covered with a tarp will sometimes get damaged by the tarp rubbing against projecting surfaces. Mark and note any damages so you can repair them before putting your boat in the water.
Next up is a thorough cleaning. Even though your boat has been protected from most environmental elements it will still need to be cleaned, inside and out, before you use it. A good washing is all that is usually needed for the exterior. The interior will benefit from sweeping floors, vaccumming cushions, wiping down all hard surfaces, and cleaning appliances and plumbing fixtures.
Any motor on a boat will need to be serviced according to the manufacturer's schedule and recommendations. Typical pre-launch maintenance includes an oil change , checking air and fuel filters. and inspecting, lubricating and adjusting control cables and levers. Old fuel should be drained and properly disposed of and the tanks filled with new fuel. If you have trouble starting the engine after storage it will probably require the carburetor to be cleaned. Old fuel, especially modern fuels with methanol added, deteriorate in just a few months leaving behind nasty deposits that can clog the jets and even gum up the float.
If your boat is on a trailer, you will want to check the tires and service the wheel bearings. You will also want to check the wiring and lights and inspect the hitch and safety chains. Then make sure the boat is properly secured to the trailer before attempting to move it.
Tools, supplies, and provisions need to inventoried. Worn. damaged, or missing tools should be replaced. Used up, clogged, expired or missing supplies also need to be replaced. Provisions (basic food and hygiene supplies and medications and first aid supplies) also need be brought up to date.
If yours is a sailboat you will need to inspect the standing rigging. Adjust as necessary and replace any frayed or damaged components. Also unfold and inspect the sails and check all the lines (sheets on the sails, halyards docking lines, etc). Repair or replace any damaged or missing items.
All safety items should be inventoried and inspected. That would include navigation lights, life vests, throwable floation devices, and signaling devices (lights, flares, horns, whistles). Larger boats may have a dingy or life raft that needs to be inspected to be sure it is serviceable.
Ready for launch!