Some years ago, I would have always advised anyone buying a boat to have it surveyed by a professional certified marine surveyor. That is no longer the case based on my own experience as both an owner of many boats and a yacht-repair-yard manager. Basically, we hire surveyors to confirm that a vessel is structurally sound and mechanically in good working order as portrayed by the seller. We expect them to uncover and report any defects that could affect our decision to buy, or end in an adjustment to the price of the vessel. And in fact, if you are financing the vessel, the finance company may require a survey. This does not guarantee you a boat free of defects, however, and there are a few exceptions where you might consider NOT hiring a surveyor.
Uncover is the operative word here because the defects to mechanical systems and structural integrity are often unseen. Obviously, surveyors will start with visual clues that lead them to believe there might be more problems than meet the eye: rust stains, leaks, broken ribs or fiberglass damage etc… Let’s say that visually there are no telltale problems. The surveyor will move on to actually try the mechanical systems, run the engine etc… Obviously for a boat out of the water, the surveyor will note in the report that these could not all be tested. That is why you should always insist on a sea-trial, with the surveyor present, when buying a boat. The prospective buyer typically pays any expenses related to sea-trialing a boat.
If you are going to buy a boat on dry land without a sea trial, I wonder if you really need a surveyor. A surveyor would only state the obvious in the report, since the engine or systems can’t be tested, and you can visually judge for yourself if there are any evident hull imperfections. So, If you insist on buying a boat on the beach where the engine(s) haven’t been run, you are running a risk. A report from a certified mechanic attesting to the condition of the engines, including compression test results, or an explicit warranty from a boat dealer may suffice in lieu of a surveyor’s report.
Structural deficiency may be even harder to detect. Damage from grounding or collision are the main concerns—and these can be covered up or imperfectly repaired. With fiberglass boats built with core material, water intrusion, particularly in climates that freeze, can cause delamination and the weakening of the hull structure. Surveyors will use moisture meters and “tap” the hull of fiberglass boats looking for water intrusion or structural voids. These are skills that border on art form and you should query any potential surveyor as to their experience with this type of vessel. Depending on what kind of material your prospective boat was built with — wood, metal, or fiberglass — I would find a surveyor experienced in that particular construction material or not bother.
In general, I think the relatively small cost of a survey is warranted. Surveyors don’t guarantee your boat is perfect; rather, they try to give you a realistic assessment of the vessel as is, so read the surveyor’s report carefully and ask questions. However, if you are not going to give the surveyor the opportunity to check all the systems or they don’t have direct experience with a given type of boat, you may be better off saving the money and foregoing the survey. Better yet, find the right pro and let them do their job, but be mindful that you’re not getting a guarantee. Boat yards deal with a lot of surveyors and can most likely recommend the appropriate pro for your type of vessel.