Optimal working conditions of a floatel along an FPSO
Examensarbete för masterexamen
Naval architecture and ocean engineering (MPNAV), MSc
Offshore operations are normally involving the connection between two or more floating structures. The arrangement, connection framework and connection effects due to encountered weather conditions etc., have been studied by a series of research and development activities. This thesis project aims to determine the optimal connection and operation arrangement with regard to minimum operation power requirement for a floating hotel under different environment conditions. The floating hotel is a semi-submersible accommodation unit, which should be attached to a turret moored FPSO and provide services to people working on the FPSO. The connection is organized by a strike gangway. However, the gangway connection is too weak to carry any loads, as it is meant for the transfer of people, tools, etc. between the two. The only way for this specific set up to work is if the accommodation unit follows the motions of the FPSO with the aid of a DP system, while fulfilling two specific conditions. Firstly, the gangway length has a tolerance of only +/-3 meters. In case elongation beyond or shortening under that limit occurs, an alarm is set off and the vessels should be detached. It is essential that the deformation of the gangway doesn’t exceed +/-5 meters at any time, as this would damage either the telescopic part of it or the connecting mechanism. Secondly, the gangway inclination also has limits. If it reaches 3 degrees on either side, the connection should be interrupted. This condition isn’t dependent on the DP system as much as on the sea-keeping, but it is the reason for the limiting sea states. A number of simulations are done in order to investigate three different orientations between the vessels (parallel, diagonal and perpendicular) under various environmental conditions. In the end of the thesis, the results are compared in order to choose a preferable/optimal relative angle for the gangway connection and specific occurrences during the simulations are discussed.
Building Futures , Marin teknik , Building Futures , Marine Engineering