Image: Jacket in transport, position. Topside removed for clarity.
Seaways Engineering International are introducing Nessie, the Novel Extended Semi-Submersible for Installation and Decommissioning (NESSI/D).
Designed to remove the Brent Alpha she will adapt to any rig. A vessel like this can lift even the largest rigs in The North Sea. Using a semi-submersible as the base, Seaways adapted their original semi-submersible design to be a massive dry dock, with a gate at one end. Getting around and under the topside makes it possible to remove the whole topside in one lift. For the jacket lift winches were added to allow Nessie to be customized to fit any situation.
Traditional cranes operate on a perceived safe limit. Nessie’s lifting capacity is far beyond any required lift. Her topside connections are solid and over-engineered. Her jacket “sling” has more connections than needed. All of these features make her a very safe option.
Image: Wee Nessie.
Nessie is a zero-heave vessel; therefore, motion compensation is an unnecessary, expensive and elusive process. With Nessie, Seaways Engineering International has eliminated much of the issues that others compensate for by being large and uncomplicated, using the natural world to our advantage. For shallow water rigs see Wee Nessie Designed to lift up to 4,000 LT.