Acoustic Doppler Current Profilers (ADCPs) – Deployment in Dungarvan, Co. Waterford

Marine Notice No. 09 of 2019
Notice to all Shipowners, Fishing Vessel Owners, Agents, Shipmasters, Skippers, Fishers, Yachtsmen and Seafarers

The ADP frames to be deployed on the seabed (image clearly showing the ADCP seabed frame with ADCP and Recovery Buoy inside the frame).

The Department of Transport, Tourism and Sport has been advised thatTechWorks Marine Ltd are planning on deploying 4 Trawl-resistant bottommounted Acoustic Doppler Current Profilers (ADCPs) frames in Dungarvan, Co.Waterford,   at locations provided below and also shown on the accompanyingAdmiralty Chart (please refer to Appendix A).

TechWorks Marine Ltd intend to deploy the ADCPs on the next neap tide betweenthe 22nd and 26th April 2019 depending on the weather. If the deployment isdelayed due to the weather, the deployment will be carried out on the next viable tide and weather window.

The frames will be on the seafloor for a minimum period of one calendar monthand a maximum period of two months (weather permitting). The ADCPs will bemeasuring currents through the water column at each location over thedeployment. This data will be used to validate a Hydrodynamic model of the areabeing developed for Irish Water.

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Not all navigation lights are created equal.

Navigation lights intended for use on power driven vessels may be different from navigation lights intended for use on sailing vessels. Although the horizontal arc of visibility is the same for all lights, the vertical divergence (i.e. vertical arc of visibility) requirements for lights on vessels under sail are larger to accommodate greater heeling. Manufacturer labeling may not discriminate between the different requirements. Navigation lights that claim compliance with the navigation rules1 may meet the vertical visibility requirements for a power-driven vessel, however, they may not comply with the vertical visibility standards for sailing vessels. Manufacturer labeling may not indicate that the lights are designed for use on power-driven vessels only.

Annex I (COLREGs section 10 and Inland 33 C.F.R. part 84.16 “Vertical sectors”) prescribes the degrees and intensities that navigation lights must meet on the vertical plane. Many boat owners may not be aware of the +/- 25° vertical light divergence requirement for sailing vessels, a 17.5° increase from the power-driven vessel standard. Installing a navigation light, designed for use on a power-driven vessel, on a sailing vessel may result in the light losing visibility when the vessel heels beyond the narrower +/- 7.5° vertical divergence angle established for power-driven vessels. A sailing vessel operator in this situation would likely not realize that the sailing vessel’s lights were not visible when heeling beyond 7.5°.

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Swarm helps pinpoint new magnetic north for smartphones

Magnetic north on the move

Since it was first measured in 1831, we have known that the magnetic north is constantly on the move. However, its tendency to slowly roam has stepped up a pace recently – so much so that the World Magnetic Model has had to be updated urgently with the pole’s new location, vital for navigation on smartphones, for example. ESA’s magnetic field Swarm mission has been key for this update.

The World Magnetic Model, the basis for many navigation systems used by ships, Google maps and smartphones, relies on the accurate knowledge of Earth’s magnetic field. Since magnetic north never stands still, the model has to be revised periodically – but a surge in pace has meant that an update was needed ahead of schedule.

Driven largely by the churning of fluid in Earth’s core, which generates the magnetic field, the magnetic north pole has always drifted, and geological evidence shows that every few hundred thousand years or so it even flips, so that north becomes south.

Around 50 years ago, the pole was ambling along at around 15 km a year, but now it is sprinting ahead at around 55 km a year. In 2017, it crossed the international date line, leaving the Canadian Arctic and heading towards Siberia.

Space compasses

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