Portable reel pipelaying method

A method for laying a continuous length of pipe on the sea bottom from a carrier vessel, in which a pipe carrying reel is rotatably mounted on a carrier vessel, reel drive motor means are coupled to the reel for driving the reel to spool up pipe in a spooling mode and for providing a dynamic braking force to the reel in an unspooling mode as pipe is unspooled from the reel, pipe straightener means are mounted to the carrier vessel downstream of the reel in the direction of unspooling for movement in a direction substantially parallel to the rotational axis of the reel, and pipe guide means are mounted to the carrier vessel downstream of the straightener means in the direction of pipe unspooling for movement in a direction substantially parallel to the rotational axis of the reel, said method comprising the steps of:

• sensing changes in tension on the pipe as it is being unspooled as a function of corresponding changes in torque on the reel drive motor means in its dynamic braking mode;
• and
• automatically adjusting the torque imparted to the reel by the reel drive motor means to maintain a balance between the torque applied to the reel by the reel drive motor means and the torque applied to the reel drive motor means by the reel to thereby maintain a substantially constant tension on the pipe in the unspooling mode.