A Hallberg Rassy 40 marine survey by Guy Nicholls, Marine Surveyor Hamble for Solent Marine Surveys. The Hallberg Rassy range are of cored FRP (GRP) construction which helps insulate the hull and deck from Swedish temperatures! The cored construction also allows lighter construction that would have been the case with single skin or monolithic construction, while in this case, the PVC foam core cannot absorb moisture as can happen when end grain balsa is used for the core material.