Since you haven't owned a boat before, the sea trail can be a sensory overload, trying to take it all in. If you have a trusted friend who knows boats, invite them along. What you want to see is how everything works, and does it "feel right" to you. The C-Dory hull is a different animal, and gives a great ride as long as you match your speed to the conditions. Be sure to see how the boat feels at speed and at whatever speed you think you'll be running the most.
Start with a walk around - does the hull look like it's in good shape? Look down the sides to see that there is a smooth flow to the surface. Look where anything is through-bolted to see if it looks tight. Open the motor cowling and see if it looks clean. Check the oil level. Does the oil look clean? When you start up the motor, does it run smooth in idle? Turn on all electronics to make sure they work. Look around at the wiring - is it bundled nicely or a rat's nest (not good)? Turn the wheel lock to lock to see if it feels smooth through the turn both ways.
Climb into the v-berth to make sure you fit. See how the coverings are on all the seating surfaces (if the boat isn't new, has the foam broken down?). Look into all the corners - is it clean? It's pretty obvious if an owner has done a quick "once over" or if the boat is thoroughly cleaned... may give you a feeling on how the owner has cared for it. While you're at that, see what kind of shape the owner's truck and/or house is in.
Out on the water, make sure the engine feels smooth all through the different throttle settings. Run the steering full rack side to side. Run the trim tabs (they won't be effective at slow speeds). Make sure the engine trim works. Ask for a radio check on the vhf. Double check all the other electronics while underway. Make sure the engine is peeing properly (water stream coming out of it).
Look at the tires on the trailer, as well as the wheels and bearings. If you can, jack up each side of the trailer and give the wheels a spin to make sure nothing is grinding. Any rust anywhere on the trailer? Bunks in decent shape? Does the boat fit well on the trailer? Check the lights to make sure they all work. If the trailer has surge brakes, make sure they are functioning.
When the boat comes out of the water, pull the plug on it to see how much drains out. Make sure the bilge pump(s) work. Any unusual water draining anywhere when it comes out on the trailer? Thump along the hull to make sure there are no "dull" spots... you may notice a different sound where bulkheads meet the hull, but not an issue as long as it doesn't sound dull when you thump it. Look at the transom as you run the motor up and down, to make sure there isn't unusual flex.
OK, that should get you started. A good marine surveyor is a sound investment if you have questions.
Have fun. It's a boat, and there isn't anything that can't be fixed - you just want to minimize additional $$$ outgo right away.
Best wishes,
Jim B.
