This is a cut from the western side of the Isles of Scilly into the Tresco Channel that lies between the islands of Tresco. It is approached and entered to the south of the Northern Rocks and Mincarlo, to pass in between Bryher and Sampson. The passage between the islands is deep but the Tresco Channel itself is shallow and drying.
Why sail this route?
With deep water leading all the way in between the islands, a commencement point than can be confidently identified by the 'Steeple Rock' West Cardinal and the vast majority of supported by a leading alignment, this cut is very straightforward cut.
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Image: Michael Harpur
It provides a convenient western approach into the Tresco Channel and thence to New Grimsby Sound

Image: Michael Harpur
However, it should always be borne in mind, that this cut requires fair weather and settled conditions with good visibility. It should not be attempt in any developed westerly component winds or if there is any significant swell. In any such conditions, the Northern Rocks and the shoals and outliers to the west of Bryer and Sampson are very particularly ugly and make for a formidable lee shore. But more specifically there are covered rocks that lie very close to the alignment mark on both sides of the approach and should a vessel be pushed off the alignment it a very dangerous situation could develop very quickly.
What are the navigational notes?


cardinal just visible
Image: Michael Harpur
Use the North West Passage

Image: Michael Harpur
From the 'Steeple Rock' waypoint steer the course bearing 058°T (reciprocal 238°T) east by northeast towards the passage which should be visible between Mincarlo Island and Bryher, passed to port, and Samson, passed to starboard, searching out the transit.

Image: Michael Harpur
The first mark is Yellow Rock which is a small rocky islet, 3.9 metres high, a little over two miles distant laying between Samson and Bryher.

Image: Michael Harpur
Once this is identified look for the Abbey Hill monument situated ¾ of a mile to the northeast of Yellow Rock on Tresco. Once identified bring the monument over Yellow Rock to provides a range mark that tracks into the second 'Bream Ledge' waypoint. Keep on transit as dangers lie close to the track on both sides.
Depart the alignment after 'Beam Ledge' waypoint as the alignment soon after passes unnecessarily close to Long Ledge, that extends from Sampson, and over an isolated shoal that dries to 1.2 metres located a little over ½ a mile along the shoal.
The 'Clovel' waypoint sets up a course to pass between the Outer Clovel Rocks and the aforementioned shoal with a further outer and covered shoal with 0.9 metres LAT over it.

Image: Michael Harpur
From here the course continues in between Bryher and Yellow Rock into the Tresco Channel. The final waypoint is close before it dries at LAT, 150 metres south by southeastward of the isolated Lubber's Rock, that dries to 1.7 metres, on Bryher side of the channel and opposite from Appletree Point.
From here, with a sufficient rise of the tide proceed to New Grimsby Sound

Image: Michael Harpur
The harbour master has placed two white posts in Cliff Field, beneath Plum Hill on the Tresco shore, that provides a transit northwest side of the sand spit clearing Lubber's Rock and the rocks from Appletree Point. It will also keep clear of Little Crab Ledge, that dries to 2.4 metres, and Great Crab Ledge, that dries to 5.3 metres.

Image: Michael Harpur
This may be used to converge with the track of the Tresco Channel crossing the Tresco Flats

Image: Michael Harpur
The complete course is 2.48 miles from the waypoint 'Steeple Rock' to 'Lubber's Rock' tending in a north easterly direction (reciprocal south westerly).
Steeple Rock, 49° 55.320' N, 006° 24.000' W
400 metres southwest of the 'Steeple Rock' west cardinal marker buoy, Q(9)15s, and as ¼ of a mile south of the rock it marks.
► Next waypoint: 1.23 miles, course ⇓ 58.02°T (reciprocal ⇑ 238.02°T)
Bream Ledge, 49° 55.970' N, 006° 22.382' W
150 metres southeast of the southeastern end of the Bream Ledge (awash at high water).
► Next waypoint: 0.65 miles, course ⇓ 48.46°T (reciprocal ⇑ 228.46°T)
Colvel Rocks, 49° 56.400' N, 006° 21.628' W
250 metres south of the Outer Clovel Rocks and north of the shoals sitting in the alignment.
► Next waypoint: 0.61 miles, course ⇓ 60.82°T (reciprocal ⇑ 240.82°T)
Lubber's Rock, 49° 56.695' N, 006° 20.807' W
150 south by southeastward of the isolated Lubbers Rock, that dries to 1.7 metres, on Bryher side of the channel. It dries from here on in LAT.