Hello, I am a marine surveyor in Palm Beach Gardens, Florida but travel the state of Florida for marine surveys.
Typically a dedicated engine survey that includes compression checks and a more hands on analysis is conducted by a separate engine surveyor. I know of two good ones in the area and can refer you to them. On a regular marine survey the engine(s) is part of the survey. As a marine surveyor, the best way to test the engine(s) is in the sea trial. This includes running the engines at WOT (wide open throttle), backing down, turing rudders hard over, etc. Also part of the survey is checking the fluids (looking for foreign substances and appropriate levels), looking for leaks, proper hose connections, advanced rust, loose engine mounts, fire hazards, proper wiring, USCG approved fuel lines, condition of fuel / water filters, sea strainers, evidence of galvanic corrosion, etc.. So the engines are pretty well covered even without the more intensive engine survey. Keep in mind that a regular marine surveyor can not turn wrenches on an engine. It is usually against their insurance and outside the scope of a marine survey so that is where an engine surveyor will come in if you or the marine surveyor feels it is necessary.
As far a credentials, I believe this is important. Marine surveying by law is unregulated so you will get some self proclaimed "surveyors" in the business. I see this quite a bit in the Caribbean.
A marine surveyor should be a member of SAMS or NAMS, two professional organizations that have a standard code of professional conduct, reporting format, and mandated annual continuing education. Also having other professional memberships and valid accredidations adds credability. background and training experience is also very helpful.
As for me I hold memberships with SAMS (Society of Accredited Marine Surveyors), ABYC (American Boat and Yacht Council), NFPA (National Fire Protection Association), and the IAMI (International Association of Marine Investigators). I am also ABYC Standards Accredited (which are safety standards most yacht builders build boats by), a former member of the U.S. Coast Guard, and a USCG Licensed Master Captain.
Remember that the cost of the survey is not the most important, it is the quality. If a cheap surveyor spends just two hours on your boat and misses several important things, it can cost you, the boat owner thousands down the road, if not your life if a safety problem is overlooked (such as a leaking fuel tank, cracked stringer, an open electrical ground, etc..). On a 35 foot vessel, a proper survey should take all day, and the report should be thorough, with plenty of pictures, and detailed descriptions of everything pertaining to the vessel. Nothing should be left out.
My website contains sample surveys and more information about marine surveys. It is at: SuenosAzules dot com.
Feel free to contact me if you need anything or have any questions. I hope this has helped.
Capt. J.B., Marine Surveyor