An Australian perspective.... brokers will always get you to sign a document in the sellers favour and pay a deposit prior to any sea trial. I did this once 20 years ago.

Subsequent boats have always had an agreed price, deposit paid and my own contract that simply states that I solely have the right to determine if the boat is acceptable and is not dependent on any surveyors report.

In the case of our Hatteras I was only interested in the mechanicals... everything else could be fixed. I'd had 15 years with 8v92s so knew what to look for. The surveyor I chose mostly did small sailboats and I led him through the Hatteras.

The owner took us for a 2 hour run at 1600RPM which was enough to run up the turbos and see any obvious issues. Perfect. In the 5 years since the boat left the USA, it had run only 90 hours in Melbourne. Clean oil, 5 new bilge pumps and we were away, Never looked back. All the mechanicals and electricals are now done. We had the yard start to quote today on external cosmetics, deck painting and repair of flybridge lounges which have some moisture deterioration.

I guess it also comes down to how much you want the boat. I was lucky and got the right boat at the right time at the right price. Its been a great four years and the next two years will give us a cosmetically completed boat. The engines and gearboxes are where to look first.