Pipe laying apparatus and method

Abstract

Apparatus and method for laying a pipeline on the bottom of an ocean wherein a wheel-like, buoyant body is adapted to carry a single, continuous length of pipe in the form of horizontal convolutions from a first site at which the pipe is wrapped on the body to a second site where the convolutions are moved into vertical positions and the pipe is unwrapped from the body and allowed to gravitate toward and to be laid on the bottom of the ocean. The pipe is wrapped on the body when the latter is horizontally disposed and floating on the water near a dock, and the wrapping can be accomplished whether the elastic bending limit of the pipe is exceeded or not. The body with the convolutions of pipe are towed to the second site while the body and the pipe remains horizontally disposed. Then a tank forming part of the body receives sea water to unbalance the body and cause it to be moved into a vertical position. In this position, the body is simultaneously towed forwardly and rotated about a horizontal axis below the upper level of the water to allow the pipe to be vertically unwrapped from the body and to gravitate therefrom. The body normally has a curvature less than the curvature at which the pipe exceeds its elastic bending limit; however the body could have a greater curvature for some specific uses. A second, smaller tank having a power actuated mechanism therein is coupled by gear means to the body near its outer periphery to rotate the latter upon actuation of the mechanism during a pipe laying operation. The mechanism can also be used to rotate the tank when the body is in a horizontal position near a dock to allow the pipe to be continuously wrapped onto the body after being formed from pipe segments connected together in end-to-end relationship.