Offshore spar production system and method for creating a controlled tilt of the caisson axis
US6027286A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 19, 1997 |
| Grant date | Feb 22, 2000 |
| Priority date | — |
| Expiry date | Jun 19, 2017 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB63B2035/442
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
An offshore system is provided of the type that includes riser pipes (30) extending up from the seafloor (44) to a tall and narrow caisson (12) at the sea surface, with the caisson moored by mooring lines (34) extending to the seafloor and anchored thereat, which minimizes bending of the upper portion of the riser pipes when the caisson drifts in severe weather. Although the caisson has a Ballasted lower end and buoyant upper end to keep its axis (20) vertical, a device is provided for applying a horizontal force (54) to a location along the caisson that is vertically spaced from the upper ends of the mooring lines, to tilt the caisson so the axis of the caisson is parallel to portions (82) of the riser pipes lying immediately below the caisson. In one arrangement, a second set of mooring lines (60) is provided, that have upper ends coupled to second locations (64) along the caisson that are vertically spaced from the upper ends of the first mooring lines. Also, a motor driven device (70) is provided for pulling on selected ones of the lines to tilt the caisson. In another arrangement, largely horizontal force transmitting members (132) extend from a lower portion of the caisson to…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.