| 摘要 |
PCT No. PCT/GB96/01755 Sec. 371 Date Jan. 20, 1998 Sec. 102(e) Date Jan. 20, 1998 PCT Filed Jul. 22, 1996 PCT Pub. No. WO96/39324 PCT Pub. Date Dec. 12, 1996A drag embedment normal load anchor ("Denla") comprises a fluke with a shank pivotally attached thereto, the shank including an anchor cable attachment point and control or restraint mechanisms whereby the shank can be set such that the cable attachment point can lie selectively in first, second, and third directions relative to the fluke centroid, the directions providing three fluke centroid angles ( alpha , beta , and theta , respectively) with the fluke forward direction (F). The Denla is part of an anchoring apparatus including a rear drogue line serving to orientate the anchor correctly at the sea bed without the need for a separate pendant line. In operation, the Denla is embedded by pulling on an anchor cable with the first fluke centroid angle alpha present; when the desired horizontal anchor loading is achieved, the shank is moved to the second larger centroid angle beta and the anchor swung back until the fluke forward direction (F) is inclined upwardly, this position constituting the normal load anchoring position. For Denla retrieval, the shank is swung forwardly to occupy the smaller third fluke centroid angle theta , and the anchor pulled upwardly in the included fluke forward direction (F). The restraint/control mechanisms are preferably located in a grease filled housing for protection and a further fluke centroid angle lower than the first centroid angle can be provided for the shank to ensure satisfactory initial burying of the anchor. The invention enables setting of the Denla and also retrieval using a single line, i.e., the anchor line. |
