An Innovative multi-purpose floating platform
FloatMastBlue was the only Blue Growth project selected for funding in the June 2017 round of the Horizon 2020 SME Instrument Phase 2, with an EU Contribution of 2.048.568€.
The floating structure is composed of:
- the submerged buoyant structure fixed to sea bed via four tension wire legs (upper point is 5m below the average sea level)
- the central pylon connecting the submerged component with the upper structure (platform)
- the upper structure (platform) that is at a height of 10m above average sea level
- the self-supporting lattice meteorological mast that is founded on the platform centre
The upgraded platform deck hosts the following:
- 3 small wind turbines and 4 PV panels for power supply
- one fuel cell for auxiliary power supply
- two cabinets with battery banks
- the main electrical cabinet (switches and protections)
- a secondary electrical cabinet (radar interfaces, Ethernet controlled power supply etc)
- a data acquisition cabinet (containing the two redundant DAQ systems and the control PC)
- a secondary cabinet for conditioners, communication system and terminals
- a 30m self-supporting lattice mast
- a LIDAR remote sensing device
- security related instruments (radar and cameras)
The foreseen instrumentation includes:
- structure safety related sensors (bilge sensors, mechanical load sensors, electrical sensors, IMUs and accelerometers, cameras etc)
- oceanographic and sea state condition sensors
- wind potential measurement sensors (anemometers, wind vanes, temperature and pressure sensors)
The system upgrade is tailored for:
- enhanced monitoring capabilities
- redundancy for communication and data acquisition
- enhanced control of power distribution
PLATFORM HYDRODYNAMIC BEHAVIOUR
Makronissos island is located to the south-east side of Attica peninsula. FloatMast was positioned to the north-east side of the island with a clear opening to the prevailing northern winds. The below pictures pinpoint the location of the FloatMast platform (WGS84 φ=37o 43’ 44.69’’N, λ=24o 9’ 20.15’’E) in relation to Makronissos island and the operating met masts in the vicinity are presented. The selected location allows FloatMast to be exposed to the prevailing northern winds with minimal effects from Makronissos island.
From the first days of operation both roll and pitch angles of the platform were recorded continuously by the two Motion Response Units that are installed at the following positions:
- One at the platform’s deck (10m above sea waterline)
- One with higher accuracy at the top of the met mast. (45m above sea waterline)
The graph presents the standard deviation of the roll and pitch angle at the top of the met mast for the time period 12/7/2019 until 13/11/2019.
The values for both motions are relatively low. For the 99.9% of the cases the standard deviation of pitch is below 0.07 deg and for roll even less setting an upper limit at 0.05 deg.
WAVE CHARACTERISTICS
The sea state conditions, at site, are also monitored during platform’s operation with Miros wave radar which was installed at the platform deck on 17/9/2019.
Correlation between significant wave height and wave peak period. The red line separates roughly the wind waves and swell.
CONCLUSIONS
The measurements provide a respectable amount of data, which have set the starting point for the optimisation and the performance evaluation of the FloatMast® platform. The collected results are very promising and especially those related to the hydrodynamic behaviour of the platform. In general, the values for pitch and roll recorded are relatively low.
