A marine survey can signify a wide number of things, but it usually describes that a condition surveyor is used to catch-all kinds of boat survey. For example, "Yacht Condition Survey", "Yacht Evaluation Survey" or "Damage Survey" may all be referred to as a singular marine survey.
Ordinarily, a marine survey is conducted when a party is interested in buying a vessel and they'd prefer the reassurance before spending the massive capital required to buy a ship. This type of Inspection, Surveys, and Investigations will provide you exact condition of the ship, what repairs may be needed, maintenance and seaworthiness.
Most buyers, (even those who know about ships ) won't be convinced enough to ascertain the condition of a boat and whether it is a sound investment. The goal of a survey is to completely detail the condition of the boat so you can make an educated decision.
When there are many associations and surveyors out there that can conduct these surveys, it's important to find the correct surveyor.
You need to look for one with experience and one registered with the professional organizations that represent surveyors, like IIMS, SINOTECH Marine or The Yacht Designers and Surveyors Association (YDSA).
Selecting a surveyor registered using the above mentioned organizations will guarantee surveys are performed in compliance with the codes of practice drawn up.