The pre-purchase survey of this Najad 400 by Solent Marine Surveys identified that the GRP rudder needed refurbishment.
The rudder was damaged with voids and splits present. Not unsurprisingly, the moisture readings that were taken to the rudder indicated a high level of moisture within the laminate. The moisture readings were verified by using both a Protimeter Aquant moisture meter and a Tramex Skipper moisture meter.

Damaged GRP rudder on a sailing yacht
Another issue, and a common one with many yachts, is that the seacock valves were not believed to be made of bronze.
Many boat manufacturers in recent years have been fitting brass (designated CW617N) valves to yachts. While they are permitted to under the EU’s Recreational Craft Directive (RCD) compliance regulations, brass valves are not of the quality one might reasonably expect.

Corroded seacock valve
They can often corrode, or dezincify, making them brittle and therefore potentially dangerous.
Better seacock valve types include bronze or dezincification resistant brass (also known as DZR, designated CW601N).
There are also newer glass reinforced Nylon composite types, such as Forespar Marelon. Or there is my preferred brand, Tru-Design, which can never corrode. These composite types also feature a PTFE filled polymer ball and ring for lubricated, smooth operation.
Other than the rudder and seacock valves the vessel was structurally sound. There was a good deal of cosmetic and maintenance work that needed an enthusiastic new owner to take on.
The Najad range offers the cruising sailor a solid and high-quality Scandinavian alternative to the more prolific Hallberg Rassy range, indeed the two ranges have many similarities.