公开(公告)号：US20210221659A1

公开(公告)日：2021-07-22

申请号：US17152226

申请日：2021-01-19

申请人： National Oilwell Varco Norway AS

发明人： Thor Strand ,  Frank Tønnessen

IPC分类号： B66D1/30 ,  B66C23/52 ,  B65G67/60

摘要： A hoisting system is for hoisting a vertically-suspended object. The hoisting system has a winch having a winch drum with a hoisting rope. A first part of the hoisting rope has a first diameter and a second part has a second diameter being larger than the first diameter. The first part is connected with a first end of the second part. The first part is an inner part on the winch drum when the winch drum is completely wound. The second part has a further end that is connectable to the object for hoisting the object. A ratio between the first diameter and the second diameter is such that the minimum breakable load of the first part differs less than a factor of four from the minimum breakable load of the second part, and preferably less than a factor of three. A corresponding method is disclosed.