Sea trial are VERY important. Basically the boat is in the water in the environment that it was designed to operate in.
What you and your surveyor should do:
- Open and Close EVERY Through hull fitting. Check for leaks and easy of opening.
- Check ALL Hoses from through hulls for leaks or cracks
- Operate the Head (if it has one)
- Turn on ALL Electronics and make sure that they work
- Look at engine oil and tranny fluid. Right level, Clean?
- Thoroughly check engine for oil/coolant leaks - especially after you have run it for several minutes - Wait till it cools a little though
- Sea Water Strainer - Clean? Put a flashlight behind it, can you see the light on the other side? Good if you can
- Engine Belts - Loose (Bad)?
- Start Motor - Easy start? Good Water flow out of exhaust?
- Run Motor from idle to max RPM in Nuetral and Under load - These should be same or very very close to the same number.
- Check Oil Pressure and Engine Temp after the Engine warms Up.
- Does the motor excessively vibrate? Alighnment? Bad Cutlass Bearing?
- Stuffing Box - Excessive Leaking/Too Dry? A drip or so every few seconds while the propeller shaft is turn is desired.
- Helm (Wheel) - Does wheel have a lot of play? Bind? Does it have stops that don't allow the ruddert to do a 360?
- Tranny - Go forward and reverse - positive "click" in between gears? (FWD/NEUTRAL/REV)
- Raise Sails - Condition of sails/halyards?
- Headsail fulrer - Smooth operation or binding?
- Standing Rig - Loose/Tight - Broken wire filamanets excess corrosion
- Sails go up and down easy?
- Mast straight
- Running rigging - frayed, worn, dirty?
That's my initial list, I am sure others will chime in.
Also, make sure that the surveyor you, and the owner or present when every major system is turned on. That way everyone sees the same thing if there is an issue.
Ask the surveyor to review each section and make notes after each section, and not a brain dump at the end. Ask questions if you are unsure about the operation or condition of anything or if you want to look at some thing not checked out.
One more very important thing - BILGE Check each compartment - Excessive water, especially if it was just splashed is a indication that something is amiss. Also, check that the bilge pump is directly wire to the battery and not through a on/off switch.