The Clipper Race fleet is preparing for the penultimate race of the series, Race 13, the Den Helder Northern Seas Challenge from Derry-Londonderry, Northern Ireland to Den Helder, the Netherlands.

The fleet begins slipping lines from the Northern Irish host port’s Foyle Marina at 1300 on Sunday, and will perform a Parade of Sail along the city’s waterfront as far as the Peace Bridge before heading back down the River Foyle towards Greencastle, County Donegal at 1415 local time (1315 UTC).

The 770 nautical mile sprint will then officially start at 1800 at Greencastle, with the teams vying for vital leaderboard points.

The fleet will then head north and around the top of the British Isles and through Pentland Firth.

The Pentland Firth is a channel which separates the most northerly tip of Scotland and the Orkney Islands and is renowned for its extreme tidal conditions, overfalls and tide races. If mistimed the tidal gate, which can run at 10 to 12 knots, can leave even the most seasoned sailor going backwards or with no choice but to anchor.

Clipper Race Chairman Sir Robin Knox-Johnston describes the key part of Race 13: “The Skippers have got to get the weather right, navigating close to land and timing the passage through the Pentland Firth. With the strong tidal conditions around the top of Scotland, if you get that wrong you can lose six hours and won’t catch up again. It is complicated and a bit of a lottery.

“To a large extent there is not much you can do about the Firth, you get there when you do and take the tide as it is, for you or against. It is a very strong reversing tidal stream,” Sir Robin added.

Once the fleet has cleared Pentland Firth, it will sail into the North Sea and set a south-easterly course towards Den Helder, The Netherlands.

This race will be heavily influenced by the depressions that come much further north across the Atlantic during the summer months. It could prove to be a testing race if conditions deteriorate in the shallow waters of the North Sea, studded with offshore oil installations.

The fleet is expected to cross the finish line off Den Helder on 22-23 July.

There is a range of activities planned for the fleet’s stay in Den Helder, including a Summer Carnival and Nautical Festival.

For more information on some of the events happening, such as live music, DJs and a food truck festival, click here.

Tonight the Clipper Race fleet will take centre stage in a spectacular festival of lights on the River Foyle called The Voyage of Sunniva. The event will be broadcast live here to mark the end of the Foyle Maritime Festival 2016. Tomorrow there will also be a live stream of the departure ceremony.

To watch Elliot Brown Watches and Sir Robin Knox-Johnston preview the Den Helder Northern Seas Challenge, click here.

To follow all the action once Race 13 starts, click here for the Race Viewer.

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