They may not yet be a pervasive hazard to cruising, but with more wind farms arriving by the year it’s fair to say they are already moving on from being something only those on the east coast or heading to Belgium, Denmark or the Netherlands need to think about.

The Danish were the first to install offshore turbines in the 1970s but the earliest applications for UK wind farms were made only in 1996.

The Crown Estate owns almost all UK coastline out to 12 nautical miles and had to agree to lease the seabed before construction could start.

Talks with the Coastguard, the RYA and other interested parties were held by the British Wind Energy Association, which then formulated Best Practice Guidelines for offshore wind farm development.

Rotor blades may be no less than 22m above MHWS which should be fine for most cruisers

The first project in UK waters was completed in 2001.

Between 2004 and 2019, however, 38 offshore wind farm sites including a number of demonstrator sites have been commissioned.

Seven more are under construction, and further sites have either been consented or are in the planning stages of development.

It’s important to note that there have been no recorded incidents involving recreational craft and offshore wind farms since the start of operations around the UK coast.

Care must be taken, nonetheless, in the navigation of farms in the UK.

Elsewhere rules differ from at home too.

Holland and Belgium have been prohibiting any leisure craft within their wind farms completely, until Holland recently permitted transit through some eastern wind parks.

They are the Offshore Windpark Egmond aan Zee (OWEZ), Prinses Amalia Windpark (PAWP) off IJmuiden and Windpark Luchterduinen (LUD) off Noordwijk (courtesy of westhinder).

Thankfully, due in part to a push from the RYA and others, the UK does not have this same issue of restricted navigation.

Some farms in the UK do have a designated passage through them, such as the wide one through Foulger’s Gat, but generally there is only a 50m safety zone around each turbine so passage through sites is absolutely fine.

The number of wind farms in UK waters is increasing year on year

‘The RYA is representing to the developers, through the government, the need to maintain proper marking, to make sure exclusion zones are not put in place around wind farms, and that they meet minimum design parameters for rotor height and charted depth so that should you choose to sail through them, you still can,’ said Stuart Carruthers, cruising manager at the RYA.

‘The RYA is a member of the Nautical and Offshore Renewable Energy Liaison (NOREL) group which works to ensure that the commercial and recreational shipping and ports industries successfully co-exist with the offshore renewable energy industries.

‘The RYA regularly monitors the development of seabed areas leased by the Crown Estate in order to assess their potential impact on recreational boating. We meet regularly with the developers involved to discuss recreational navigational safety and respond to national consultations on behalf of recreational boating.

‘Mostly consultation in the UK has worked well over the years and cruisers are still able to navigate through wind farms with the 50m restrictions from each pylon in place. However, this is a constant process and it is worth making sure you are following procedure on your end to ensure an easy passage. Currently, something under discussion – and I’m about to meet with the MCA about this – are support vessels (or Service Offshore Vessels to give them their proper title) that take engineers out to the farms and dock onto the individual units using a bridge between boat and pylon.

Currently some farms are applying to have safety zones around these boats. From our perspective and that of the MCA, these are covered off by the ColRegs as they are simply a vessel of limited maneuverability.

‘This is just one area where the wind companies often try to nibble at the edges of the rules so we need to stay vigilant.’

Carruthers says that the system currently works pretty well and almost all cruisers report very little trouble understanding how to navigate the farms but he warns it is worth making sure you know your rights.

‘There have been a few instances where patrol boats have incorrectly told cruising boats that they may not navigate through a farm. In the instances where this has happened it has usually been a case of the crew of the patrol boat not being properly briefed so there is nothing particularly underhand going on but it can be difficult to get your point across in such circumstances.

‘We are seeing wind farms expand and they are increasingly becoming something all sailors in the UK need to understand. The Rampion windfarm off Brighton is set to expand and we would expect that to grow a decent amount. They are going up Lincolnshire coasts and more are coming in the Liverpool Bay area.’

Navigation marks

Wind farms are marked by aids to navigation and are required to be conspicuous by day and night, with consideration given to prevailing conditions of visibility and vessel traffic.

In certain cases cardinal marks may also be permanently placed adjacent to wind farms.

During construction, standard cardinal marks are used around the working area.

A corner structure, or other significant point on the boundary of the wind farm, is called a Significant Peripheral Structure (SPS) and must be marked with lights visible from all directions.

These lights should be synchronised to display simultaneously an IALA ‘special mark’ characteristic, flashing yellow, with a range of not less than five nautical miles.

There is anecdotal evidence of turbulence downwind of wind farms causing rogue guets, though currently little conclusive evidence

Aids to navigation on individual structures are placed below the arc of the rotor blades, typically at the top of the yellow section.

As a minimum, each SPS will show synchronised flashing characteristics. In some cases there may be synchronisation of all SPSs.

In the case of a large or extended wind farm, the distance between SPSs should not normally exceed three nautical miles.

A key focus for the RYA has been to ensure that the farms are positioned well offshore.

‘Initially when the government started approving wind farms we were assured they would be 12 miles offshore,’ Caruthers explains.

‘This was not the case for a few of the earliest farms but in recent years that has been upheld. We feel this is a very important point. There is due diligence to be done in terms of your passage planning when it comes to wind farms, we take the view that if someone is 12 miles off the coast then they are likely going on a fairly long trip so we can assume thorough passage planning.

‘If the wind arrays get closer then there is a possibility they could interfere with coastal day-cruising which could become an issue.’

Interference effects

Stuart Carruthers is the RYA’s Cruising Manager and is heavily involved in the association’s discussions with wind farm operators

‘Anecdotally I have heard that there are turbulence effects from the farms,’ says Carruthers.

‘But if you think about it, when they design the array, they have to leave space between each turbine so it does not have an effect on another in the farm, so I think the effect if any is probably minimal. I certainly don’t think you absolutely need to consider wind direction in reference to whether you will be downwind of an array in your planning for this reason.

‘Where wind farms can interfere, however is radar where they do have a slight blocking effect so it’s unwise to rely on radar around them. Again anecdotally we have heard from RYA members that they have an effect on VHF but there is not evidence to support that.

‘We have also heard that due to the cabling there could be an effect on compasses. Again there is no evidence to support that, but I think it is possible if not likely.’

Wind farm dos and don’ts…

Do

• Update your charts – paper and electronic – at least annually, particularly in the North Sea and off Liverpool, where new windfarms are being added or extended every year.
• Check regulations for each wind farm when sailing in foreign waters. Some allow passage through the windfarm, others don’t.
• Keep an increased lookout for shipping, as sailing around windfarms may force small yachts into channels also used by larger shipping.
• Watch out for turbulence and sudden gusts when passing downwind of turbines.
• Take extra care when navigating near windfarms in restricted visibility. As new structures are being added and work boats may be moving unpredictably, it’s best to err on the side of caution and keep clear.
• Monitor a windfarm’s working VHF channel if available.
• Check your mast height. The lowest point of the rotor blades have a least air draught of 22m above MHWS – plenty for most yachts.
• Make use of windfarms as navigation marks, often showing the location of shoal patches.

Don’t

• Sail within 50m of a turbine, as each turbine has an individual exclusion zone.
• Pass too close to work boats operating in windfarms. They don’t have exclusion zones, though some may claim they do, but may well be restricted in their ability to manoeuvre and should be respected as such.
• Forget about tide and wave energy. A number of sites on the English south coast, the Welsh and Irish coasts and off Northern Scotland have development sites that may need extra care.