Risk management.

Risk Management Study

In their relentless pursuit of safer shipping transits, OMC’s focus is aligned not only with that of the regulators and users but also with the International Maritime Organisation (IMO) whose agenda is to ensure compliance with the safety standards it is developing.

OMC’s expertise in UKC risk management enables it to offer clients a study assessing the likelihood of a potential grounding and associated safety breaches at their port or waterway (as well as potential economic savings).

Such a study typically involves determining the Touch Bottom Probability (TBP) of a ship transiting a waterway under an existing static rule or under DUKC® advice. The results are compared to internationally acceptable criteria for TBP. A Monte Carlo approach is commonly used with distributions applied to each UKC factor. This approach ensures that by repeatedly sampling the various UKC distributions over a large range of conditions (typically involving more than 2 million sampled transits), the large number of UKC residuals generated sufficiently describe the UKC residual probability distribution.

 

Ship Motion Analysis

Full scale ship motion studies are essential in quantifying actual UKC requirements and validating OMC’s Dynamic Under Keel Clearance (DUKC®) system models. They deliver the answer to the question, what is the safe UKC of a large ship transiting a depth restricted waterway?

OMC pioneered the use of high accuracy Differential GPS (DGPS) systems in the measurement of ship motions, including squat, heel, heave, pitch and roll. By placing three DGPS receivers on the ship, horizontal and vertical ship motions can be determined to sub-decimetre accuracy.

To date, OMC has carried out measurements on more than 300 ships throughout Australia, New Zealand, Asia, Europe and the USA. These have included all major ship types with varying depth/draft ratios, stability characteristics and transit speeds, channel configurations, tidal patterns and wave climates.

Where wave response is the primary concern, OMC International’s award winning ship motion measurement tool OMC iHeave®   – which won the prestigious 2012 International Bulk Journal Awards ‘Innovative Technology’ (Marine) category in November 2012 – can be deployed. OMC iHeave® is a fully self-contained device that can be simply mounted inside the bridge of a ship, in the one location, by a pilot or approved person onboard.

Using high accuracy solid-state inertial motion sensors in combination with GPS, OMC iHeave® records short duration (up to 60 seconds) vertical ship motions. OMC iHeave® provides a cost effective method to collect wave response data for a large number of transits.

Understanding ship motions also underlies the determination of the actual motions on mooring line loads at berth and over the full berthing period. OMC would take measurements on-board moored ships under wind wave, current and and passing ship scenarios to validate OMC’s moored ship models, including its Berth Warning System (BWS).

By scientifically predicting the forces of the ship motions on the mooring lines and fenders, and forecasting wind and waves out to 48 hours, the BWS supports terminal operators in their decisions about safe operation of berthed ships.

 

UKC Requirement Study

This information is used to evaluate existing waterway operating practice and to plan future operations.

Combining an in-depth understanding of port operations and UKC management with its ship motion measurement and analysis capabilities, OMC is uniquely positioned to undertake UKC requirements studies.

The major objective of these studies is to quantify the variation in UKC requirements through a restricted waterway given the range of met-ocean and sailing conditions that could occur.

OMC has undertaken a number of UKC studies based on DUKC® methodology. The major objectives of such studies are to:

  • Evaluate and make recommendations on static UKC rules, including met-ocean operating limits and likelihood of seabed contact;
  • Determine channel accessibility for different ship classes;
  • Assess the changes in port access due to seasonal variations in met-ocean conditions; and
  • Advise on ship speed restrictions and port operating procedures, and assess the impact of optimising speed profiles on UKC.

 

Feasibility Study

The benefits of the DUKC® can be determined in terms of the increase in safety, ships’ drafts and sailing windows, channel capacity, and port accessibility.

OMC can assess the potential benefits of DUKC® to a port or waterway through a feasibility study. By modelling the port’s existing operations, and simulating operations with a DUKC® system in use, the impact of the DUKC® can be evaluated.

A feasibility study will provide the information necessary to assess the potential UKC risk, and how the DUKC® can manage this risk, as well as the potential economic savings that DUKC® can provide to the port’s operation.