E1-M3A

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Project title and acronym

Improving mooring design using integrated load cell and transmitting AIS message with selected buoy parameters (IMLOC-AISPAR)

Host facility

E1-M3A

Modality of Access

MoA2 – Partially remote (the presence of the user is required at some stage, e.g. for installing and uninstalling an instrument)

Description

The oceanographic buoys are moored to the sea bed to ensure it stays close to its nominal position. The water depth may range from shallow water to Deep Ocean of several thousand meters. The mooring will be subject to the environmental forces at the deployment site (winds, waves, current profile) and must be designed accordingly to ensure the buoy stays put. The mooring design process involves both general experience and various computer tools to reach the final mooring design.

We do however see that some combinations of water depth and environmental conditions are difficult for the numerical tools and the experience from similar states are limited.

By using a load cell below the buoy connected to the data logger to measure the actual pull in the mooring can help overcome this limitation. The load cell may be programmed to provide the min and max load over a given time period, such as every 15 min. Data from the load cell will contribute to the general experience and allow fine tuning of the numerical tolls utilized in the mooring design process. Furthermore, the buoys may be equipped with an AIS (AtoN) unit to notify passing vessels about the buoy position to minimize the risk of interference. Experiences of the past have shown that in case of a mooring line failure the station can drift for several miles and can be a potential danger for nearby vessels.  

Poseidon system Athos station drifting after mooring line failureThe message from the AIS unit may in addition contain selected parameters measured by the buoy. Thus passing vessels may get information on winds, waves and currents as measured by the buoy. The AIS message is also accessible by the general public, who may use the buoy information for their professional needs as well as for recreational purposes.

By implementing the AIS message with ID 8 in the data logger software, this goal may relatively simply be achieved. The message format is fixed and may accommodate the following parameters:

Wind (speed, direction, gust), air temperature, humidity, dew point, air pressure, visibility, water level, current profile (speed, direction), waves (height, period, direction), water temperature, precipitation and salinity. The total number of parameters is about 30.