bo for shallow sea - installation manner and its oar installation null of ring

摘要

PURPOSE: To safely and simply set up a shallow sea derrick on the sear surface without use of a floating crane. ;CONSTITUTION: Floaters are coupled to a shallow sea derrick having been built on the ground, to an arbitrary height, and then the derrick 1 is towed to a boring site in such a condition that the lower end of the derrick 1 is floated up from the sea bottom by means of the floaters 2. Thereafter, grounding legs 4 provided on the derrick 1 are grounded on the sea bottom, thereby it is possible to set up the derrick at a prescribed position.;COPYRIGHT: (C)1994,JPO&Japio