11.3 Adverse Weather Routeing
- Some vessels and vessel operators may transit alternative routes during periods of adverse weather. Adverse weather includes wind, wave and tidal conditions as well as reduced visibility due to fog. Adverse weather can hinder a vessel’s standard route, its speed of navigation and/or its ability to enter the destination port. Adverse weather routes are assessed to be significant course adjustments to mitigate vessel motion in adverse weather conditions. When transiting in adverse weather conditions, a vessel is likely to encounter various types of weather and tidal phenomena, which may lead to severe roll motions, potentially causing damage to cargo, equipment and/or discomfort and danger to persons on board. The sensitivity of a vessel to these phenomena will depend on the actual stability parameters, hull geometry, vessel type, vessel size and speed.
11.4 Baseline Data
- No specific adverse weather routeing was observed within the baseline data studied, however the long term 12 month AIS analysis (Appendix E) showed a minor weighting towards summer months for cargo vessels, tankers, and oil and gas vessels i.e., a minor increase in numbers was observed during summer. This may indicate that such vessels prefer to pass further inshore, i.e. outside of the shipping and navigation study area in adverse conditions (which may be more likely during winter months). However, a genuine reduction in transits in the shipping and navigation study area due to adverse conditions may also be a factor, as could AIS coverage.
- There is open sea area inshore of the Array (the closest operational wind farm is Seagreen 1 Offshore Wind Farm, located 27 nm inshore as per section 7.3), and therefore the Array is not considered as hindering any preference for inshore routeing in isolation. Cumulatively, if all screened in projects are considered, there will remain sea room available inshore, between Morven Offshore Wind Farm (pre-application) and projects closer to shore including Seagreen 1 Offshore Wind Farm (operational) and Berwick Bank (determination).
11.5 Consultation
- The following key points of relevance to adverse weather were raised during consultation (see section 4):
- Smyril Line stated that vessels would likely not transit through offshore wind farms in adverse weather conditions.
- It was suggested at the Hazard Workshop that vessels would likely seek to make the most direct safe transit possible during adverse weather.
- Wilson Ship Management indicated transit choice through the area would depend on weather conditions, and stated preference for passing inshore.
- This input is considered as broadly aligning with the findings of section 11.4, i.e. vessels are more likely to transit in inshore locations during adverse weather rather than in the vicinity of the Array.
12.1 Very High Frequency Communications (Including Digital Selective Calling)
- In 2004, trials were undertaken at the North Hoyle Offshore Wind Farm, located off the coast of North Wales (UK). As part of these trials, tests were undertaken to evaluate the operational use of typical small vessel VHF transceivers (including Digital Selective Calling (DSC)) when operated close to wind turbines.
- The wind turbines had no noticeable effect on voice communications within the North Hoyle array area or ashore. It was noted that if small craft vessel-to-vessel and vessel-to-shore communications were not affected significantly by the presence of wind turbines, then it is reasonable to assume that larger vessels with higher powered and more efficient systems would also be unaffected.
- During this trial, a number of telephone calls were made from ashore, both within and offshore of the North Hoyle array area. No effects on the telephone calls were recorded using any system provider (MCA and QinetiQ, 2004).
- Furthermore, as part of SAR trials carried out at the North Hoyle Offshore Wind Farm in 2005, radio checks were undertaken between the Sea King helicopter and both Holyhead and Liverpool Coastguards. The aircraft was positioned offshore of the North Hoyle array area and communications were reported as very clear, with no apparent degradation of performance. Communications with the service vessel located within the North Hoyle array area were also fully satisfactory throughout the trial (MCA, 2005).
- In addition to the North Hoyle Offshore Wind Farm trials, a desk-based study was undertaken for the Horns Rev 3 Offshore Wind Farm in Denmark in 2014 and it was concluded that there were not expected to be any conflicts between point-to-point radio communications networks and no interference upon VHF communications (Energinet, 2014).
- Following consideration of these reports and noting that since the trials detailed above there have been no significant issues with regards to VHF observed or reported, the presence of the Array is anticipated to have no significant impact upon VHF communications.