In accordance with Section 1-1-2 of this Supplement to the ABS Rules for Conditions of Classification ?C Offshore Units and Structures (Part 1)@ the classification ? A1 Liftboat ? AMS is to be assigned to liftboats meeting the requirements of this Guide. A liftboat is a self-propelled@ self-elevating vessel with a relatively large open deck capable of carrying equipment and supplies in support of various offshore mineral exploration and production or offshore construction activities. A liftboat also has the capability of rapidly raising its hull clear of the water on its own legs so as to provide a stable platform from which maintenance and construction work may be conducted. Liftboats with an overall hull length of 61 meters (200 feet) and above are to comply with the ABS Guide for Building and Classing Mobile Offshore Units.