The operating envelope and environmental demands for hydraulic fracturing and stimulation treatments in the North Sea are increasingly larger and more complex. As a result, a generation of vessels designed and built in the 1980s are increasingly unable to achieve operational, economic and/or environmental goals. Thus, a new generation of vessels must be designed specifically to meet these European requirements.The design characteristics of a new vessel can be split into five categories: (i) stimulation plant (ii) marine systems (iii) environmental protection (iv) welfare of the crew and (v) regulatory compliance. All five categories are critically important to achieving the stated goals for the new generation of European vessels, and all require careful integration of current cuttingedge technology with forward-thinking design concepts that will enable technical evolution over the expected 30-year lifetime of the new vessels. This paper will outline the most significant problems faced by the current generation of stimulation vessels, compare current technological solutions to those problems, and demonstrate that integrating those technologies in a new vessel can achieve performance and flexibility far beyond what is possible by retrofitting them on an older vessel or in a modular system on the deck of a supply boat.Tail-end production will have an increased importance in the North Sea and in all offshore production as a large number of producing fields near the end of their life. The effective deployment of production enhancement with stimulation vessels has a major part to play in extending field life.

This paper describes how four European navies have been able to work together for over twenty years in order to support their marine Tyne, Olympus and Spey gas turbines, used for surface ship propulsion, through two internationally agreed Memoranda of Understanding (MOUs). It shows how the MOUs came into existence, what their main aims are, how they are organised and how MOU business is conducted to achieve these aims. The final part of the paper discusses the merits of the existing MOUs and presents an insight into how they, and other MOUs currently under discussion, may develop in the future.