Patent ID: 7954658
Filing Date: 2011-06-07
Classification: B63B,E02D,G01V

Abstract:
1. A process for lowering equipment of large size and mass through a resonance zone to the sea bottom, in which said equipment to be lowered to said sea bottom is submerged some meters and suspended by means of a sling, supported on a stern roller of a first tug boat, the process comprising the following maneuvers: adequately tying said sling to a first cable of said first tug boat by using a tri-plate as an auxiliary component by means of connections and screws; approaching a second tug boat toward said first tug boat until a point where said second tug boat may transfer a second cable from said second tug boat to said first tug boat; attaching said second cable from said second tug boat to said auxiliary component by means of connectors and screws, in order that said first cable, said second cable and said auxiliary component compose a connection, wherein said connectors may carry out pivotal movements around holes of said auxiliary component; releasing said sling from said first tug boat and lowering said sling until said auxiliary component passes said stern roller of said first tug boat, with said equipment being suspended by said first and second cables and being supported on stern rollers of both of said tug boats; maneuvering both of said tug boats to within an adequate distance from one another and extending, simultaneously, said first and second cables, thereby permitting a restricted descent of said equipment; renewing an approach of both of said tug boats toward one another, thus permitting a further descent of said equipment; and carrying out maneuvers and cable control of said tug boats, based on control of three variables, namely relative positioning of said tug boats, speeds of winches, associated with said cables, and of said tug boats and the lengths of said cables, wherein said pivotal movements of said connectors function to almost entirely absorb wave induced oscillations of both of said tug boats, without transmitting said oscillations to said equipment, as said equipment is lowered through said resonance zone toward said sea bottom.