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Ormonde offshore wind farm, Irish Sea

SEA JACK is a specially constructed barge loaded with advanced equipment that enables offshore tasks to be carried out with great precision and control. The sheer size of SEA JACK means that it can operate at many of the deeper water locations currently being considered for turbines and can work in areas with high tidal ranges.

The vessel’s competent Manitowoc M1200 Ringer crane makes it possible to install large components at sea, and the platform has sufficient storage space for a number of bulky components. Furthermore her specially designed jacking system is very fast and thereby increases operational efficiency.

As with all our vessels, SEA JACK has her own A2SEA crew operating and maintaining the vessel. This gives us absolute control over our work practices and means we can ensure the highest standards of safety and quality.

You can see more of SEA JACK in the BBC’s 2011 documentary on this high-capacity lifting vessel.

Tech Specs


Vessel: SEA JACK

Type of vessel: Self-elevating platform

Classification: Germanischer Lloyd

Flag: Danish



Length: 91.20 m

Breadth: 33 m

Draft: 5.5 m

Leg length: 50.4 m

Deck load: 20 t/m²

Free deck space: 2,500 m² (subject to deck layout)

Total net deck load: 2,500 t (depending on stability)

Operating water depth: 6–30 m (depending on tide, penetration)


Jack-leg System

Number of legs: 4

Jacking system: Wire

Jacking engines: 8x DEUTZ BF 8 M 1015MC (each 400 kW)

Jacking speed: 0.8 m/min–1.0 m/min

Spudcan footprint: 64 m²

Wave limit jacking: 1.5 m Hs (subject to site specific assessment)


Main Crane

Type: Manitowoc M1200 Ringer

Main boom length: 42–115 m

Crane capacity: 800 t (subject to boom configuration)


Mooring & Anchor System

Winches: 4 x 30 t line pull, hydraulic driven

Wire lengths: 900 m

Anchors: 4 x 10 t


Tank Capacity

Fuel: 200 m³

Fresh water: 95 m³

Sewage tanks: 65 m³


Power Sources

Main generators: 2 x 390 kVA, 1 x 350 kVA

Power supply: 3 x 380 V, 50 Hz, 3 x 220 V, 50 Hz

Deck power supply: 3 x 690 V, 50 Hz, 3 x 400 V, 50 Hz, 2 x 230 V, 50 Hz, 1 x 110 V, 50 Hz


Client’s Accommodation

Personnel: 23 persons

Cabins: 23 single cabins

Office: 1 with 2 work desks and meeting table (seats 6)

Other (shared with vessel crew): Rest lounge, Mess room, Gym facilities




Download technical specifications for SEA JACK


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