procedure for towing in the water of long tubes with a length of up to several kilometers

摘要

A method for towing pipes up to several km in length (esp. for use in the offshore industry) in water and then laying them on the sea bed, comprises the following steps :(1) a large diameter main pipe is made and placed inside it are at least one relatively small diameter cooling pipe, at least one tow line and at least one device to allow for expansion due to water freezing inside the pipe ; (2) the main pipe is filled with (pref. fresh) water ; (3) the cooling pipes are used to freeze the water inside the main pipe to form ice along its entire length and cross-section, making the main pipe more rigid and opt. securing the tow line.