A review of Very Large Floating Structures (VLFS) for coastal and offshore uses

Very Large Floating Structures (VLFS) have sparked tremendous interest and been the focal point of several articles. The Megafloat is particularly well known for coastal use. The aim of this article is to review the concept of VLFS, showing how they are deployed for both coastal and offshore areas. For these offshore areas, the MOB project (Mobile Offshore Base) is the design that has been most fully developed. Although the Megafloat has been widely studied, attention should also be given to other VLFS for offshore purposes. Among these is the MOB mentioned earlier, as well as other VLFS, including the Pneumatic stabilized platform (PSP) or Versabuoy. These floating structures have been designed in response to logistic developments, mainly to create floating harbours and airports, both on the coast and offshore. They have a wide variety of functions. After providing an overview of each VLFS, the different models will be compared. Their advantages and disadvantages will be assessed according to the depth in which they work and their proximity to the coast. Another comparison is then made between the VLFS and other floating structures that have already been in use on the coast and offshore: pontoons, barges, ships and semisubmersible platforms. It must be added that all of the VLFS are only at the design stage, with the exception of the Mega-Float in Tokyo Bay, the only manufactured VLFS in existence. These projects have not been carried out. Nevertheless, they have inspired research on behaviour-related problems in VLFS design. One area in particular is hydroelasticity. For coastal waters, the increase in costs of real estate and the sensitivity towards the protection of coastal areas will have an impact on the development of these structures in the 21st century. Their use in open ocean water- offshore- requires further studies in order to lower the costs and to offer more reliable solutions.