Be the purpose of the survey, pre-purchase, condition or other. It should determine if the vessel is safe to use for its intent and what maintenance is required.
Most of us have seen the sign on the yacht club wall or heard the phrase:
Boat: noun: A hole in the water into which one constantly pours money. Do not let this be you, get a survey.
A marine survey will give you a report. This will cover, what you are getting yourself into and the likely implication of any defects found.
Certain designs of boat will have recurring problems an experienced surveyor will understand these and know what to look for.
Spheredawn has to date never undertaken survey and found no faults there is always something!
A PDI or handover survey on a brand new luxury motor yacht always springs to mind in which 55 faults were found 2 of them making it dangerous to put to sea and a further 20 of them non cosmetic significant defects.
You may also find it difficult if not impossible to get finance or comprehensive insurance (dependant on age) on a vessel with out a survey. Spheredawn reports are acceptable to all the major underwriters and finance houses.
Most buyers even experienced DIY boaters would have trouble in giving a detached and unbiased opinion together with, the day in, day out experience of looking at hundreds upon hundreds of vessels. The experance a good marine surveyor will bring is invaluable to your purchase or in some cases even your life.
In the ideal scenario a surveyor will be involved right from the stage before a yacht is even chosen. The purpose being to give advice on what to be looking for.
A weekend cruiser is not ideal for blue water sailing however we do come across people who have been sold to in this way.