Marine structure erection - using ballasting and lightening to position and locate large sections (NO 19.12.77)

摘要

The platform is supported on a substructure and the improvement described concerns the method for mounting the platform on the substructure. The substructure is located on the sea-bed and the central shaft, in one piece, extends above sea level to the height at which the base of the platforms will be placed. The significant difference in this process is that the support columns descending from the platform are hollow, allowing them to be ballated and lightened at will, thus causing the platforms to float at the required height. During transport to the site the columns are ballasted so that the platform floats low in the water. They are lightened at the site so that the platform floats slightly higher than the top of the support column. When the platform is in the correct position water is allowed into the hollow support columns thus causing the platform to sink onto the support column of the substructure.