Call your broker or the boat owner to inform them you will be conducting an extended inspection. They may be expecting a cursory inspection. This will let them know you will be there for about an hour per boat. Most purchasers will select a boat based upon the living area and general condition of a boat. A lot of buyers don't look very deep at the condition until a survey and haul out.
Ask for any previous surveys of the boat. These will let you know any previous defects and if the owner has addressed them. Be prepared to not receive any surveys on your boats. Some owners don't get them and some may have "misplaced" them if there were a lot of things found by the previous surveys.
Ask for the Hull Identification Number (HIN) so you can research the history. Most history reports are around $30-$50. These reports will show any reported accidents or damage to a boat. How to read your HIN. Click here to check for recalls.
NADA will also give values for boats. Their values don’t take into account everything that can be added to a boat and they also don’t account for age of anything added. For instance, sails that are 10 years old are a little less valued than brand new sails but this is not accounted for with the NADA site. The best use of this would be to not add any extras through the NADA site and just get the basic value for the boat then add value for anything added and the condition of those items.
Ask the broker or owner to remove all fasteners for your inspection. You can be held liable for any damage done if you use tools to remove any covers. Also have this done before your surveyor gets there unless the owner or owner's broker is there to do this, as the surveyor will not likely use tools to remove any covers or panels.
When you're looking at the listing, be sure to annotate the exceptions i.e. dingy, dishes, grill or other items that may not be staying with the boat. No reason to look at anything you won't be getting with the purchase.
Notebook and pencil - used for jotting notes as well as any drawings you may need
Audio/video recorder - you can use some type of recorder to dictate your thoughts on the boat as you are going over it to save time. Most smartphones have an app that can do this.
Digital camera - Remember to secure it to you or have a good waterproof/floating camera so you don't need to budget for a new one along with your new boat.
Flashlight - Many places you want to inspect will be dark, the back of lockers, lazarettes, or the engine compartment.
Phenolic Resin Hammer - use it to test for damage to the hull and deck. Don't bang a hole into a nice new boat though. Just tap like you're looking for a stud behind a piece of drywall.
Inspection Mirror - used to see the backside of hard to reach places. A small camera or camera phone may suffice.
Multimeter and Moisture meter - These are both handy gadgets if you know how to use them. If not, get a class or leave them at home.
White Rag - To check for oil leaks.
Coffee stir sticks – Use them to check the oil, antifreeze, etc.
120 VAC GFCI Outlet Tester – Used for quick test of any outlets. These can be picked up for less than $10.
When you get to the boat take a picture of the boat with the name to document the start of a new boat if you are doing multiple inspections.
Systematically go through the entire boat recording your findings on an audio/video recorder or in your notebook. Document all areas of interest with the camera.
Tapping the deck with the phenolic hammer near stanchion basses may give you an indication if the deck has started to delaminate or has a wet core. Most boats have a cored deck and stanchions are often places where the water intrusion can start due to the loads they’re often subjected to. Please do not pound on an Awlgriped deck. Use the hammer for tapping, not pounding.
Look for cracks in gelcoat. Most spider cracks are normal. Parallel cracks in the gelcoat often indicate stressing of the fiberglass. Star-shaped cracks are usually the result of impact.
I will not go aloft since I don't know how well maintained the rig is. Also, most owners don't want you to go aloft due to insurance issues if you fall. Also blood stains are hard to clean off a nice white deck. You can get a lot of information of any deficiencies with a good 10 megapixel camera. You may not be able to see something right away, but when you get home and look at the pictures on a larger computer screen you will be able to pick up most cracks or rust spots indicating pending failures.
I have added a word document with the inspection checklist I used when looking for my used boat. Feel free to take it and modify it how you see fit when looking for your boat.