Jack Sound
The twin most westerly tips of Wales are Pen Dal-aderyn, just south of St David’s Point, and Wooltack Point to the west of Dale, both on the Pembrokeshire Peninsula. Still further to the west of these protruding fingers are the islands of Ramsey and Skomer, each separated from the mainland by narrow channels of water - Ramsey Sound and Jack Sound respectively. Their importance is the short cut they offer on passage round this tip of Wales, and their challenge is the pilotage and passage planning involved for a safe transit, ideally of both sounds in one go. The waters outside the islands are not free of navigational issues: the archipelago of The Bishops and Clerks lies off Ramsey, while Skomer looks out to The Smalls, Hats and Barrels, and Grassholm. Fast tidal streams complicate passage of all these areas.
Many yachts choose to go through the sounds for a faster, smoother trip, although careful pilotage and timing is essential. Jack Sound, lying between Wooltack Point and Midland Isle, is beset by hazards on all sides ready to threaten the unwary. Cable Rock and The Anvil lie to the east side, the Crabstones reef to the west, Tusker Rock to the north-east, Blackstones to the south-west, and The Bench occupies the south-east corner. Add a tidal race that can peak at 6 knots causing violent overfalls in strong wind over tide conditions and it is clear why Jack Sound has a bit of a reputation. Yet choose calm weather and slack water and you'll wonder what all the fuss is about. We have even enjoyed the passage under spinnaker.
The key issue is to establish the time of slack water relevant to Milford Haven. The slack before the northgoing stream starts at HW -0425 hours at Springs (-0300 at Neaps), and the slack before a south-going stream starts at HW +0200 hours at Springs (+0300 at Neaps). These slack periods last for approximately 20 minutes, though it is generally safe to pass through up to an hour before or after slack as long as the wind direction is with the flow. To risk passage later or earlier, especially in high contrary breezes, is to court disaster as swirling currents, exacerbated by swell, rise up against the wind to form standing waves that kill your speed and steerage. Don't be tempted – it is best to wait for safe conditions in the nearby South or North Havens on Skomer, depending on which side of the race you are.
Gladly, the actual pilotage of the transit is fairly straightforward. Going northwards, identify the two sharp pointed rocks of the Blackstones lying 450m south of Midland Island. Start about 70m to the east of these rocks, looking for Tusker Rock on a bearing of 26°T. Keep strictly on the direct line of this course to clear all the hazards on either side, but take care not to drift to port, even if the boat’s heading seems to be towards the mainland as you ferryglide along the safe line. When you're due west of Tusker Rock, you can relax and choose your onward track. The southward passage is a simple reverse of the same plan, starting to the west of Tusker Rock but with a course of 201°T to leave the Blackstones to the east.
Faithfully follow these guidelines and you will be rewarded by a safe and enjoyable shortcut between Milford Haven and St Bride’s Bay, and can enjoy being the centre of attention as the coast-path walkers on the cliffs admire the intrepid yacht passing through the rock-verged narrows.