Heavy transport, courtesy: Dockwise
General information
In wet tows and heavy lift transports of offshore structures such as jack-ups, jackets and spars, wave-induced ship motions can result in critical accelerations and inertia loads in the precious cargo. Not only extreme material stresses but also fatigue damage may occur.
As such inertia loads at critical locations and the response of the structure cannot be simply defined by a ‘limiting wave height’ nor be evaluated by ‘good seaman ship’, on-line presentation of actual measured and computed data on board is required.
Quite often the fatigue life consumption of a structure during dry transport is significant. A benefit of monitoring motions of a structure during its transport is that an accurate record of the consumed fatigue life during that transport is available. As a result the remaining fatigue life of the structure in service can accurately be assessed.
In wet tows and heavy lift transports of offshore structures such as jack-ups, jackets and spars, wave-induced ship motions can result in critical accelerations and inertia loads in the precious cargo. Not only extreme material stresses but also fatigue damage may occur.
As such inertia loads at critical locations and the response of the structure cannot be simply defined by a ‘limiting wave height’ nor be evaluated by ‘good seaman ship’, on-line presentation of actual measured and computed data on board is required.
Quite often the fatigue life consumption of a structure during dry transport is significant. A benefit of monitoring motions of a structure during its transport is that an accurate record of the consumed fatigue life during that transport is available. As a result the remaining fatigue life of the structure in service can accurately be assessed.
Services & Activities
MARIN provides systems that enable a continuous real time measurement of all motions and wave conditions during a complete voyage or marine operation. these systems also offer advanced processing of data and screen presentations of the results.
The system computes, displays and stores:
MARIN provides systems that enable a continuous real time measurement of all motions and wave conditions during a complete voyage or marine operation. these systems also offer advanced processing of data and screen presentations of the results.
The system computes, displays and stores:
- Accelerations, velocities and motions in a user defined point of interest (time traces)
- Incident wave records
- Combined or processed data, such as
- Fastening loads
- Fatigue damage
- green water risk
- Statistics and spectra
- Comparison with user defined criteria
- Graphical presentations
Wave and motion monitoring is conducted for various operations where wave induced motions are critical such as:
- Heavy lift transports
- Precious cargo
- Offshore installation
- Mooring & Offloading
- Towing
- High Speed Craft
- Dredging operations
Facilities & Tools
MARIN has developed for this purpose a compact system for continuous on-board monitoring of waves and vessel motions as well as for the computation of their consequences to the ship and cargo. This system, which can be used as advisory system to the crew and which stores data for post-voyage analysis, is based on three components:
MARIN has developed for this purpose a compact system for continuous on-board monitoring of waves and vessel motions as well as for the computation of their consequences to the ship and cargo. This system, which can be used as advisory system to the crew and which stores data for post-voyage analysis, is based on three components:
- A ship-based wave radar, which can be mounted on the bow
- A compact motion sensor unit measuring all six degrees of freedom (Marine Quality Kit)
- A laptop PC
The encountered wave elevation can be monitored by means of Doppler level gauge radar installed at the bow of the vessel. This radar is looking slightly forward onto the wave surface and is measuring the relative wave height. By integrating the wave data with the measured motions on the bow the absolute wave elevation can be derived.
The MQK measures real-time and fully automatically the accelerations and motions in six degrees of freedom by means of accelero meters and angular rate gyros. The sensor unit measures 0.25 x 0.17 x 0.12 [m] and can be placed at any location on the ship. It is connected to a laptop PC.
The MQK measures real-time and fully automatically the accelerations and motions in six degrees of freedom by means of accelero meters and angular rate gyros. The sensor unit measures 0.25 x 0.17 x 0.12 [m] and can be placed at any location on the ship. It is connected to a laptop PC.
Experience record
The list below gives a review of transport monitoring projects carried out at MARIN:
The list below gives a review of transport monitoring projects carried out at MARIN:
- Heerema, Valdemar AB transport monitoring, 2004
- Heerema, Benguela-Belize tow monitoring, 2004
- Dockwise/Petrobras, Wave and motion monitoring P-40 transportation, 2001
Most recent papers on transport monitoring by MARIN
(Complete overview of papers can be found under Publications)
(Complete overview of papers can be found under Publications)
Offshore Monitoring; Real World Data for Design, Engineering and Operation
van den Boom, H., Koning, J. & Aalberts, P., Offshore Technology Conference (OTC), Houston, 2005
Design criteria for weather routed transport
Aalbers A.B., Nataraja R. and Anink S., RINA Heavy transport and lift conference, London, 2005
Safetrans: A New Software System for Safer Rig Moves
Aalbers A.B, Cooper C.K, Nowak S, Lloyd J.R, Leenaars C.E.J. and Vollen F., Proceedings Jack-up Conference, London, 2001
Voyage Acceleration Climate: A Comprehensive Statistical Method for the Evaluation of Design Loads for Offshore Transport
Aalbers, A.B. (MARIN), Leenaars, C.E.J. (Dockwise), Quadvlieg, F.H.H.A. (MARIN), Offshore Technology Conference (OTC), Houston, 1996
van den Boom, H., Koning, J. & Aalberts, P., Offshore Technology Conference (OTC), Houston, 2005
Design criteria for weather routed transport
Aalbers A.B., Nataraja R. and Anink S., RINA Heavy transport and lift conference, London, 2005
Safetrans: A New Software System for Safer Rig Moves
Aalbers A.B, Cooper C.K, Nowak S, Lloyd J.R, Leenaars C.E.J. and Vollen F., Proceedings Jack-up Conference, London, 2001
Voyage Acceleration Climate: A Comprehensive Statistical Method for the Evaluation of Design Loads for Offshore Transport
Aalbers, A.B. (MARIN), Leenaars, C.E.J. (Dockwise), Quadvlieg, F.H.H.A. (MARIN), Offshore Technology Conference (OTC), Houston, 1996
Most recent articles on transport monitoring written for MARIN Report
(complete overview of articles can be found under Publications)
(complete overview of articles can be found under Publications)
Sloshing impacts captured in 110 full-scale tests
Mirek Kaminski & Edwin van de Bunt, MARIN report, 2009
SAFETRANS
Albert Aalbers, MARIN Report, 2006
Tow monitoring for fatigue assessment
Pieter Aalberts, MARIN Report, 2006
Mirek Kaminski & Edwin van de Bunt, MARIN report, 2009
SAFETRANS
Albert Aalbers, MARIN Report, 2006
Tow monitoring for fatigue assessment
Pieter Aalberts, MARIN Report, 2006
Contact
For more information on how MARIN can assist your organisation with full scale motion measurements, please contact MARIN's Trials & Monitoring department
For more information on how MARIN can assist your organisation with full scale motion measurements, please contact MARIN's Trials & Monitoring department