Internal waves are known to occur in most ocean areas, especially the deep ocean
where stable stratification is often found. While engineering operations have hitherto
largely been confined to well-mixed shallow seas (such as the North Sea). ne\' petroleum
discoveries have prompted a move into areas (e.g. west of Shetland) where internal
waves are more likely to be a problem. The implications of internal waves for safety
in offshore operations have been raised by Osborne, Burch and Scarlett (1978) and by
Bole, Ebbesmeyer and Romea (1994). The presence of internal waves in sea areas of
current interest to the UK offshore industry has been confirmed by Sherwin (1991).