Cruise Ship Collision Barrier

A new type of collision control barrier is under design and development.  The design brings a very large cruise ship (or any other vessel) gradually to a stop, converting the vessel’s initial kinetic energy to potential energy stored in two structures on either side of the barrier.


Hydrodynamic analysis with OrcaFlex is used to confirm and improve upon closed form analytical solutions developed by STA.

Designs have been developed for cruise ships up to 333m length with gross tonnage 150,000 and velocity 6 knots.

Marine Salvage Dynamics – Sewol Salvage

Sewol Side Lift Partly Emerged 1

Sewol Salvage: Stewart Technology Associates worked as Technical Advisors to Shanghai Salvage Company using STA software and were responsible for all dynamic analysis of the complex lifts in the open ocean environment.  All lifts are dynamically sensitive and involved cutting edge marine salvage dynamics. Analyses were performed with waves in the time domain using FEA (OrcaFlex).

Marine Salvage Dynamics of Sewol Salvage raised with ZPMC 12,000 ton floating crane and 1,200 ton lifting frame.

32 HMPE upper slings, 8 balance slings, 34 pairs of steel lower slings.

Fully coupled 6 DOF time-domain dynamic analyses in OrcaFlex with diffraction forces on the Sewol and ZPMC crane barge.  All individual sling tensions computed during all stages of the Sewol Salvage.

Sewol and Floating Dry Dock 1

Sewol wreck transfered to semi-submerged floating dry dock in open ocean.  OrcaFlex time domain dynamic analysis of three main vessels, lifting frame and all slings.

The following video describes how STA has examined the issues of unusually low freeboard and trapped water on the pontoon deck.

The video provides a description of how OrcaFlex is used to cope with time domain calculations of the wave motions of the floating dry dock when the deck becomes submerged and the buoyancy of the wing tanks is of critical importance.

More details of the accident can be found at:



The  portfolio item below provides a short OrcaFlex Tutorial with a Mooring Analysis example.

SPM Squall Analysis

CALM Buoy modeled in OrcaFlex

CALM Buoy modeled in OrcaFlex used in Wind Shift, or Squall Analysis of Suezmax Tanker

CALM Wireline1

Wireline view of SPM CALM Buoy modeled in OrcaFlex.

A Suezmax tanker is moored via a hawser.  View list of STA software.

SUEZMAX Perspective1

Suezmax tanker seen in shaded perspective view in OrcaFlex, moored to SPM CALM buoy during squall analysis.

The portfolio item below provides a short OrcaFlex Tutorial with a Mooring Analysis example.

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