STABILITY, SEAKEEPING

& ocean ENGINEERING - MARITIME RESEARCH PROGRAMME

The aim of this research programme is to help the maritime industry to determine the operational limits and safety of ships and floating platforms in waves. It also supports the development of innovative concepts for blue growth.

sub programmes

Ship and platform performance

Within this sub-programme the ship and platform response and their performance in operational to extreme conditions are investigated and further improved. In order to predict ship or platform performance accurately, it is important to have:
• A good representation of the encountered environmental conditions and operational profile;
• A good modelling of the linear and non-linear responses due to these environmental conditions;
• Solutions to assess the overall workability of the studied ship or platform.
The first is covered within the Waves and Impacts programme, whereas the second and third item are covered within this sub-programme.

Ship and platform performance

Within this sub-programme the ship and platform response and their performance in operational to extreme conditions are investigated and further improved. In order to predict ship or platform performance accurately, it is important to have:
• A good representation of the encountered environmental conditions and operational profile;
• A good modelling of the linear and non-linear responses due to these environmental conditions;
• Solutions to assess the overall workability of the studied ship or platform.
The first is covered within the Waves and Impacts programme, whereas the second and third item are covered within this sub-programme.

Stability & safety at sea

This sub-programme deals with the assessment of the dynamic stability, and thereby safety, of ships and platforms operating in a seaway. At present, safety regulations with regard to ship capsize are primarily based on static stability concepts linked to the righting lever curve of the ship. The focus of this research is to apply and further develop MARIN’s hydrodynamic models to assess dynamically the stability and safety at sea on first-principle basis.
Typical points of interest are:
• intact stability in large waves that may lead, for example, to excessive accelerations on cargo, parametric roll and/or broaching;
• damaged stability of in particular (large) passenger ships and naval platforms,
• ship control in adverse weather conditions such as minimum degree of control for safe return to port.

Stability & safety at sea

This sub-programme deals with the assessment of the dynamic stability, and thereby safety, of ships and platforms operating in a seaway. At present, safety regulations with regard to ship capsize are primarily based on static stability concepts linked to the righting lever curve of the ship. The focus of this research is to apply and further develop MARIN’s hydrodynamic models to assess dynamically the stability and safety at sea on first-principle basis.
Typical points of interest are:
• intact stability in large waves that may lead, for example, to excessive accelerations on cargo, parametric roll and/or broaching;
• damaged stability of in particular (large) passenger ships and naval platforms,
• ship control in adverse weather conditions such as minimum degree of control for safe return to port.

COMPLEX (MULTI-BODY) OPERATIONS

This sub-programme deals with operations at sea in which multiple, interacting and possibly flexible bodies are involved. This is typically of interest for navy and offshore operations (replenishment at sea, launch and recovery of small craft, maintenance of wind offshore farms), but also to predict the response of most renewable energy devices, platforms for living or working at sea, and aquaculture.

COMPLEX (MULTI-BODY) OPERATIONS

This sub-programme deals with operations at sea in which multiple, interacting and possibly flexible bodies are involved. This is typically of interest for navy and offshore operations (replenishment at sea, launch and recovery of small craft, maintenance of wind offshore farms), but also to predict the response of most renewable energy devices, platforms for living or working at sea, and aquaculture.
FUTURE OF OCEAN ENERGY AND SHIPPING
Better Ships, Blue Oceans’ to make ships cleaner, smarter and safer and to contribute to a sustainable use of the seas. Linking renewable energy, zero emission shipping and floating islands.
SEMI-SUBMERSIBLE IN WAVES
In the last decade, several mooring line failures have been reported for offshore structures in the North Sea. Such failures mostly occurred in severe sea states and are believed to be due to overloading of the mooring line loads. These failures showed the need to improve the methods and procedures in predicting the wave loads in harsh environments. The wave drift forces are especially important as they are a key parameter in the design of the mooring system. However, they tend to be underestimated by linear potential-flow based methods, which are still the work-horse design tool in the offshore industry. Model testing can be used to assess the wave drift loads and calibrate the numerical tools, but they are usually only performed in the final stage of the design.

In their research project Frédérick Jaouën, Arjen Koop, Tim Bunnik showed that MARIN’s in-house CFD code ReFRESCO is able to accurately calculate the wave drift loads on semi-submersibles in steep waves. This includes the prediction of the non-quadratic nature of the wave drift forces, which cannot be predicted by potential-flow based tools. The numerical results were validated based on the model tests performed on the Stena Don platform in 2018. MARIN wishes to thank Stena for supporting us in this research project, and therefore contributing to our mission: Better ships, Blue oceans.

Interested in optimizing your design by minimizing the drift loads? Contact Frédérick Jaouën.
WIFI WAVE IMPACTS ON OFFSHORE WIND TURBINES
Improved design methods for wave impacts on offshore wind turbines.