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KHM Portsmouth / Safety and regulations / Regulations


To assist the safe passage of small craft to and from Portsmouth Harbour a Small Boat Channel for vessels less than 20m in length including Personal Watercraft (PWC)  has been created on the western side of the harbour entrance. The 50 metre wide Small Boat Channel is shown on Admiralty charts 2625 and 2631.  Its northern and southern extremities are at Ballast Pile (50 47.62N 001 06.83W) and No 4 Bar Buoy (50 46.97N 001 06.48W) respectively. Small boats are reminded that they can be difficult to see and the harbour entrance is a blind bend to larger vessels and traffic leaving the camber.

The following rules apply:

  • Small Boats must enter and leave the harbour through the Small Boat Channel.
  • All craft fitted with engines, when navigating in the Approach Channel to Portsmouth Harbour, are to proceed under power between No 4 Bar Buoy and the Ballast Beacon. Vessels greater than 20 metres in length may only use the Small Boat Channel with the express permission of KHM on VHF Channel 11. Permission will only be granted if traffic levels are sufficiently low to allow safe passage for all vessels using the Small Boat Channel.
  • The Small Boat Channel may only be entered or exited by vessels approaching from the east at its northern or southern extremities.
  • A traffic pattern is established around Ballast Beacon; Small Boats entering the harbour are to pass close to the east of Ballast Beacon and those exiting close to the west.
  • Small Boats crossing the harbour entrance may only do so to the north of Ballast Beacon or to the south of No 4 Bar Buoy.
  • Small Boats, save those listed below, are not to loiter in the Small Boat Channel.
  • Small Boats should remain on the Starboard side of the Small Boat Channel and should adjust their speed to remain within the Small Boat Channel rather than overtake and be forced into the main channel.
  • All vessels using the Small Boat Channel are to leave 4 Bar Buoy to port, whether heading inbound or outbound.
  • In vicinity of BC Outer (red beacon), all vessels are to pass to the east of the beacon except those joining or leaving the Small Boat Channel at the Inner Swashway who are to leave it to port. This area can become extremely busy, particularly during the summer months, and mariners joining here should converge with caution and avoid forcing others out in to the middle of the harbour entrance. Similarly, all mariners should be alert to strong cross currents in this area which can sweep vessels in to the main channel.
Guide for small crafts
Archer class patrol boat P270 coasting through Portsmouth harbour

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