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.The pass between Sampson and Bryher as seen from Bryher with Yellow Rock in the
center
Image: Michael Harpur
center
Image: Michael Harpur
It provides a convenient western approach into the Tresco Channel and thence to New Grimsby Sound connecting with Tresco Channel crossing the Tresco Flats . This cut in may also be used to provide a deeper approach to New Grimsby Sound from St Mary’s Road. By using the North West Passage to the 'Steeple Rock' West Cardinal it provides a means of avoid the shallower sections of the Tresco Channel crossing the Tresco Flats between The Hulman and Little Rag to enter from deep water to the north of the sand spit on Tresco Flat. All that is required to continue to New Grimsby Sound is a sufficient rise of tide to pass over 0.7 metres LAT, as opposed to 1.7 to cross the sandbar on the flats. It may also provide an easier exit out of New Grimsby during fresh winds from the northwest, round through north, to the northeast, when it can be difficult to depart. In suitable conditions, it can also provide an enjoyable piece of pilotage.
Mincarlo to the northern rocks, a deadly coast in poor conditions
Image: Michael Harpur
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?
Mincarlo Island, as seen over Bryher's Colvel Rocks, with the Steeple Rock
cardinal just visible
Image: Michael Harpur
cardinal just visible
Image: Michael Harpur
Use the North West Passage to arrive in an area about 250 metres south of 'Steeple Rock' west cardinal marker buoy, Q(9)15s. It is moored about 350 metres southwest of the rock and serves to mark both the entrance to the North West Passage and this cut between the islands. As always, beware of lobster pot buoys in and around Scilly.
Mincarlo Island
Image: Michael Harpur
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.
Yellow Rock sitting in a position midway between the islands
Image: Michael Harpur
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.
Abbey Hill monument on Tresco
Image: Michael Harpur
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.
The cut joining the Tresco Channel
Image: Michael Harpur
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 by steering northeastward to connect to the track of the Tresco Channel crossing the Tresco Flats .
The view out through the pass from the front of the harbour master's posts
Image: Michael Harpur
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.
Tresco Harbourmaster's alignment marks
Image: Michael Harpur
Image: Michael Harpur
This may be used to converge with the track of the Tresco Channel crossing the Tresco Flats to continue into New Grimsby Sound.
Plumb Hill posts in alignement
Image: Michael Harpur
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.