Doing a pre-purchase survey

Question
Hi again Mr. Blanchet,

One more quick question for you.  When getting a
pre-purchase survey done on a new boat (27' powerboat), how
important are:
a) thermal imaging
b) sea-trial.

Explanation: The owner has the boat on dry land and he told
me that usually they "just spray a hose" over the hull.  
What do you think of that?  Also, is thermal imaging
useful, overrated hype, or what?  I'm sure it will cost me
significantly more to do a sea-trial and/or thermal
imaging, so I want to be sure they are worth it.

Answer
Hi Dan

I've never heard of a surveyor conducting thermal imaging on a vessel, but many scan the fore deck, transom, and hull area below the waterline with a moisture meter to determine the extent of osmosis.

Seldom do surveyor's of pleasure crafts undertake a sea-trial. That's not their responsibility, nor might they be experienced or qualified to do so, and provide an intelligent report.

However, it is adviseable to have a qualified marine mechanic do a compression test on the engine, and check the water circulation for any obstructions, including belts, etc.

I do not understand the purpose of hosing down the hull. Is this a pre-requisite for thermal imaging?

Safe Boating
Ron Blanchet