You are a paid pessimist. Your job is to find faults. This makes you unpopular. Ethics is the armor that protects you from pressure.
1. Conflicts of Interest
Scenario: A broker offers you a "finders fee" for referring work.
Ruling: IMMEDIATELY REJECT. You work for the Buyer. Taking money from the Seller/Broker side compromises your independence.
Also Illegal: Surveying a boat you are selling, or surveying a boat for a friend/relative (you cannot be objective).
2. The "Soft" Report
Scenario: The seller asks you, "Can't you just say the engine is 'Serviceable' instead of 'Rusted'?"
Ruling: No. You report the condition as observed. "Rusted" is a fact. "Serviceable" is an opinion. Stick to facts.
3. Confidentiality
The report belongs to the Client (Buyer). You cannot send a copy to the Broker, the Seller, or the Yard without the Client's written permission. Even if the Broker begs. Even if the deal falls through.
Conclusion
Your reputation takes 20 years to build and 5 minutes to destroy. If a deal feels "slimey," walk away. No fee is worth your integrity.