King's Harbour Master Portsmouth

NAVWARN No 72/22

1. During a recent survey, depths less than 10.5m on the edges of the dredged channel at Portsmouth Harbour entrance were discovered. Depths as shoal as 9.9m were found on the edge of the 10.5m dredged area near Fort Blockhouse. Encroachment extends up to 11m into the maintained depth area on the western side of the Harbour entrance and up to 9m on the eastern side.

2. The areas highlighted do not represent a significant narrowing of the minimum width of the channel in the Harbour entrance (which remains at 100m) and it is assessed that there is no danger to the normal movement of marine traffic in the area except when vessels are operating at the limit of available water. In such cases, mariners are advised to exercise particular caution and ensure their vessels remain in the centre of the channel when passing through the Harbour entrance.

3. A monitoring survey will be conducted in November 2022 and the areas dredged as a priority at the next planned dredging campaign, either later this year or early in the first three months of 2023.

4. The following Portsmouth NAVWARNs remain in force: 69/22, 67/22, 63/22, 60/22, 42/22, 15/22, 71/20, 57/20, 44/20, 04/20, 15/19, 60/18, 75/17, 33/17, 27/14, 57/12, 52/11 & 70/22.


Monday 26 Sep 2022