Marine Transportation

Marine operations are one of the core activities in Semar. From small cargos to heavy topsides and module, transportation operations can be covered by our teams on different levels individually or in an integrated project:

Design and seafastening: Our engineering services can cover the design, structural verification or third-party verification of transport grillages and seafastening structural components. Our experience in steel design helps us provide our clients with fit-for-purpose designs focusing on safety, strength, costs and ease of use and handling.

Motion response analysis: In cases where the cargo can affect the motion of the transport vessel, motion response analyses can be performed to identify critical dynamic responses of the cargo/vessel system. Our experienced hydrodynamic department can cover hydrostatic and linear and non-linear hydrodynamic analyses including Computational Fluid Dynamics (CFD)

Project engineering and on-site assistance: Through the entire project, preparation of equipment and procedures for transportation can be prepared considering all aspects of fabrication, installation, handling and marine operations. Master mariners and engineers are also available from Semar to assist during mobilization, operation and de-mobilization, offering a consistent project follow-up and continuity from design to operation.


›  DOF – IMR Angola Jumper reinstallation – 2017

›  OHT – Hywind floating foundation transportation (3 600t) – 2017

›  Master Marine – Sheringham shoal wind turbine transportation – 2011

›  AMC – Lan Tay transportation and float-over (5 500t) – 2001-2002

›  Statoil – Gullfaks platforms (42 000 – 48 000t) – 1996-2000

›  AMC – Øresund bridge caisson installation (200m high pylons, 20 000t dry weight) – 1996-1997

›  NC – Heidrun Module Support Beams Loadout transportation and mating (9 000t) – 1992-1995

Areas of competence

›  Stability analyses of the transportation vessel

›  Hydrodynamic motion analyses of transportation

›  Structural analyses of transportation vessel with application of hydrodynamic loads

›  Seafastening/Support grillage structural design and draughting

›  Cargo handling operations

Hywind Substructure

For the world’s first floating wind farm, OHT was contracted to transport the substructures from Fene (Spain) to Stord (Norway) before float-off and upending by ballasting. Transport was done on the semi-submersible vessel Albatross. The substructures were loaded out with trailers onto the vessel before securing the cargo by assembling the full grillage structures. After arriving at site, removable parts of the grillage are dismounted to allow floating off the substructures using the submersible capability of the vessel.

For this phase, Semar provided assistance to OHT in the design of transport grillages and operation aids. The scope involved competence that Semar has in structural design and analysis, marine design, draughting and marine operations. The design was also submitted for approval to the Marine Warranty Surveyor (MWS). Overall, Semar was able to provide consistent consultancy and close cooperation with the client and MWS in a demanding schedule.

Scope of Work

›  Design of transport grillage with removable parts

›  Design of securing structure for removable parts

›  Structural FEA of the grillage, vessel deck and securing structures

›  Design of handling aids and outfitting

›  General assistance during fabrication

Key figures

Client OHT
Operator Statoil ASA
Project duration 2017
Project characteristics​ Three voyages, with five substructures
91m long and 14.8m diamater columns
Weight of one substructure is 3 600t