What is the route?
Why sail this route?Although not explicitly marked by lateral marks, the North West Passage is wide, deep and a primary commercial route that has supporting lit cardinal markers at key points. It is simply a matter of following two range marks into Saint Marys Road. The first is dedicated to supporting the close approaches to the entrance and leading a direct path to the second range mark. This later range mark is the main route into Saint Mary’s Road that is shared with Broad Sound. So, with the support of good navigation and position, in good weather, the North Channel presents no difficulties to leisure craft, night or day at any stage of the tide.
Image: Michael Harpur
It is the ideal route for vessels arriving/departing to or from Ireland and Irish Sea havens. Although the western side of the islands have the greater number of isolated offshore hazards, in good conditions from the above locations, it is a far better approach than defaulting to the principal Saint Mary’s Sound entrance. More often than not, the confidence of its obvious landmasses, crowned by prominent lighthouses, make this the preferred approach of all newcomers. But for a vessel approaching from the northwest and north, Saint Mary’s Sound only servers to add about 15 miles, required to round the islands, more complexity and the possibility of additional tidal issues that can be experienced between the landmasses of Saint Mary’s and St Agnes.
But this is not an option in any boisterous weather as the Northern Rocks and the shoals and outliers to the west of Bryer and Sampson make for a formidable lee shore. These collide with the Atlantic swell three or four miles offshore and with groundswell, strong tidal streams and eddies threw into the mix, large areas of breaking seas result. Add any other weather elements to this and things can get ugly here very quickly. Likewise, though the fairway is wide, should any vessel accidentally stray from its margins they will quickly find themselves in great peril amidst shoals and hidden rocks.
So this is best considered a fair-weather route as with the nearby Broad Sound route, though it could be said to be slightly better.
Tidal overviewToday's summary tidal overview for this route as of Saturday, April 17th at 15:50. The southeast-going stream in the North West Passage, spring rate 1.5 knots, begins -0415 Devonport (+0230 Dover). The northwest-going stream, spring rate 2 knots, begins + 0115 Devonport (-0425 Dover). Westward of Steeple rock at spring tides during the northwest-going stream, a strong tidal ripple may be experienced.
(HW Dover -0425 to +0230)
(Tidal flow )
Ends in 01:16:27
(Sat 10:12 to 17:07)
(HW Dover +0230 to -0425)
Starts in 01:16:27
(Sat 17:07 to 22:37)
What are the navigational notes?
Range marks intersection point, 49° 54.444' N, 006° 22.570' W
This is the intersection of the 127° T alignment of the aforementioned St Agnes / Tins Walbert with the main Broad Sound alignment of the northern summit of Great Ganilly Island just open north of the slope of Bants Carn on St. Mary's Island, bearing 059° T.
► Next waypoint: 1.16 miles, course ⇓ 58.85°T (reciprocal ⇑ 238.85°T)
St Mary's Sound, 49° 55.042' N, 006° 21.033' W
On the Broad Sound 059° T alignment of the northern summit of Great Ganilly Island just open north of the slope of Bants Carn on St. Mary's Island and in the southwest end of Saint Mary's Road.
What is the best sailing time?May to September is the traditional UK Sailing season with June-July offering the best weather. The British Isles weather is highly variable, and the amount of bad weather varies quite widely from year to year. This is because they are islands positioned between the Atlantic Ocean and the large landmass of continental Europe. As a result, the entire area lays under an area where five main air masses meet and alternate:
- • Tropical Maritime Air Mass - from the Atlantic
- • Polar Maritime Air Mass - from Greenland
- • Arctic Maritime Air Mass
- • Polar Continental Air Mass - from central Europe
- • Tropical Continental Air Mass - from North Africa
Depending on the movements of the jet stream, any and all of these air masses can come in over the isles, creating weather fronts where they meet and bringing with them all types of weather.
The prevailing winds for the British Isles as a whole are from the western quarter which generally blows for two-thirds of the year predominantly from the southwest. Gales from the westward are felt in all seasons, but from November to March, inclusive, they are most frequent and generally last three or four days. Of these, a southwest gale is considered to be the most powerful system. The winter period is largely characterised by wind and rain.
The fine summer weather of the sailing season is typically punctuated by the passage of an Atlantic depression that bringing periods of strong wind and rain, and sometimes poor visibility. These gales rarely cause surprises as they are usually forecasted well in advance. Good weather windows of 48 hours are easy to predict but any longer than that there's an increasing chance of change.
Fogs are frequent in all parts of the Channel and are formed both on the English and French coasts. In summer they only obscure the land in the morning and are readily dispersed by heat or a light breeze. But the moist haze, driven in by westerly winds from the sea, tends to linger and is only dispersed by strong winds. In the eastern part of the Channel, it is rare for the land to be completely free from mists. The only exception is when the wind is from the northeast which makes the mist free coastline highly distinctive from a great distance.
With thanks to:Micheal Harpur eOceanic.
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