Ross, The following is from the SAMS website:
This is the most comprehensive type of inspection, and is strongly advised when purchasing a new or used vessel. Condition and overall operation of the vessel should be examined. This covers structural integrity, electrical systems, the propulsion system, the fuel system, other machinery, navigation equipment, miscellaneous on-board systems, cosmetic appearance, electronics, and overall maintenance as well as an out-of-water inspection and a sea trial.
This inspection is performed so that the insurance company can determine whether or not the vessel is an acceptable risk. They are interested in structural integrity and safety for its intended use. Most insurance companies require a survey on older boats. They will also want to know the vessel's fair market value.
So it'll be be an in water inspection, here's their wwebsite:
The Society of Accredited Marine Surveyors®, Inc. - (SAMS®)