Print Email Facebook Twitter Spudcan hydrodynamics: Analysis of hydrodynamic coefficients of spudcans in proximity of the seabed during jack-up installation Title Spudcan hydrodynamics: Analysis of hydrodynamic coefficients of spudcans in proximity of the seabed during jack-up installation Author Hoes, R.S. Contributor Huijsmans, R.H.M. (mentor) Huijs, F.A. (mentor) Faculty Mechanical, Maritime and Materials Engineering Department Maritime Transport Technology Programme Offshore and Dredging Engineering Date 2015-06-15 Abstract This thesis researches the change of the hydrodynamics of jack-up spudcans close to the seabed and the influence of this change on calculated jack-up motions. Two GustoMSC jack-up designs are selected as typical: a large drilling jack-up (CJ-70), and a small wind turbine installation vessel (NG-2500X). Limits for allowable wave heights during jack-up installation are determined by factors including station keeping and wave loading. Spudcan impact loading is an additional factor that becomes governing in long period waves. A better understanding of jack-up motions during installation can improve impact prediction methods and this could result in more favorable installation limits. Forced heave oscillation tests have been done at decreasing distances from a towing tank bottom with a skirted spudcan and a hexagonal spudcan. A thin disk was used to validate the model tests. Added mass of both models was found to increase with decreasing distance to seabed and with increasing amplitude. Quadratic heave damping was found to increase with decreasing distance to seabed. The latter was significantly larger for the skirted spudcan. Static frequency domain analyses were done with WAMIT and in-house GustoMSC software to investigate the influence of the measured increase of added mass and damping on the motions of typical jack-up’s during installation. Spudcan motions of the CJ-70 showed significant decrease in long period waves. The spudcan motions of the NG-2500X showed a small decrease in sea states with long period waves. The decrease of CJ-70 motions could improve installation limits in these conditions. Further research is however needed to analyze neglected effects and to quantify the improvement in installation limits for drilling jack-up’s with skirted spudcans. The decrease of NG-2500X motions is considered to be not significant enough, to indicate a possible improvement in installation limits for small wind turbine installation vessels, with hexagonal spudcans. Subject SpudcansJack-upclose to seabedadded massdampingdragforced oscillationjack-up installation To reference this document use: http://resolver.tudelft.nl/uuid:9d74dc50-c4c5-49a1-a07c-f41455320d90 Part of collection Student theses Document type master thesis Rights (c) 2015 Hoes, R.S. Files PDF Thesis_RS_Hoes_-_Spudcan_ ... stract.pdf 780.5 KB Close viewer /islandora/object/uuid:9d74dc50-c4c5-49a1-a07c-f41455320d90/datastream/OBJ/view