Here's a partial list off the top of my head;
Review the maintenance records for trailer showing regular bearing service. If electric over hydraulic, test the break-away switch and battery. Check the tires, including the spare, for wear, proper inflation and any signs of deterioration from being parked for extended periods. Inspect the brakes. Check the label on the trailer to make sure that the GVWR is at least 9500 lbs for an R-25. 10,000 lbs. would be better. Inspect the frame, brakes lines and wiring. Inspect the jack, winch and winch strap. Check the lights on the trailer. Check the trailering lights on the boat while on the trailer. Take it for a drive. Test the brakes. After a few miles, use an infrared thermometer to check the four hubs to make sure they are all within 5-10 degrees of each other.
Review the maintenance logs for boats showing regular oil and filter changes, fuel filter changes, coolant changes, impeller changes and air filter cleaning/replacement. Make sure that you have the manuals for the boat and each of the components; thrusters, engine, instrumentation, etc.
Inspect the condition of the bottom, bottom paint and the hull. Inspect the propeller and anode, propeller shaft, rudder, thrusters and thruster anodes. Inspect the water intakes. Check the swim ladder and the supports for the swim step. Turn on all three battery switches. Test the trim tabs and check for leaks at the actuation cylinders. Inspect the trim tab anodes.
Check the navigation lights and interior lights. Check the deck lights using both the interior and exterior switches. Test the VHF radio. Test the AM/FM radio. Play a CD. Test the 12V DC "cigarette lighter" outlets. Test the windlass using the switches on the bow as well as the switches at the helm. Inspect the anchors, chain and line. Check the fire extinguishers, CO detector, life jackets, flares, fenders and dock lines. Inspect the curtains and canvas including bimini, front window cover, cave cover and aft window cover. Test both horns. Test the refrigerator in both AC and DC modes if applicable. Inspect the interior trim. Fold the seats. Look for signs of leaks. Check the windshield wipers. Open each hatch and slide each window and screen. Check the table and its supports.
Plug in the AC system to shore power and test each of the circuits (Water heater, stove, AC, etc.) Check each AC outlet. Test the AC battery charger. Leave the water heater and battery chargers on for a while.
Test both bilge pumps and sensors. Take a sample from the Racor fuel filter and check for contamination or water. Check the oil level and condition for both the engine and transmission. Check the coolant level. Inspect the hoses and belts. Check for excessive corrosion. Check the sea strainers. Inspect the wiring in the battery and engine compartment.
Check the rear thruster and depth sounder compartments for signs of excessive water. A little in the bottom is OK. Check the four drain holes (lateral into compartments from outboard and fore-aft from rear thruster and depth sounder compartments to bilge/engine compartment) for signs of blockage. Check for the autopilot rudder position sensor attachment and leaks at the steering actuation cylinder. Load test each of the batteries. Move the Y-valve counter-clockwise to the macerator position. Confirm that the macerator works, then return the Y-valve clockwise to the pumpout position and seal it there with an electrical tie.
Test the pressure water system. The water should be hot after 10-15 minutes with the water heater on. Test each spigot and the shower head in both hot and cold modes. Test the shower sump pump. Turn off and disconnect the AC power.
Install the drain plug and launch the boat. Open the though-hulls. Check for leaks. Start the engine. Check for smoke at start-up and thereafter. Make sure there is cooling water exiting from the exhaust. Look for exhaust leaks. Test the bow and stern thrusters. Test the head. Test the raw water wash down system. Test the generator. Assure that it runs the air conditioning and other appropriate accessories. Check the depth sounder, chart plotter and radar.
Go for a ride. Check the voltage from the alternator. Run the engine at varying speeds after warm-up. Someone with a Cummins may be able to provide expected temperatures, speeds and fuel consumption at various RPM's. After 10 minutes, check the stuffing box with an infrared thermometer to assure that it is less than 20 degrees warmer than the water temperature. Check the leak rate from the stuffing box. One drip every 5-10 seconds is the goal while running. Check for oil or exhaust leaks. Test the ability of the auto pilot to track a course and to navigate to a waypoint. Check the cabin heater and fan. Reinspect everything in the engine compartment after cool down.
If you want to, you can hire a mechanic to inspect the engine more thoroughly. He can check the prop shaft alignment, fuel injectors, oil condition, mixing elbow, etc. Most surveyors don't do this.
Sign the papers and enjoy your new boat! Please feel free to send a private message with questions.
Rich
