Friday, 21 October 2016

Queen Elizabeth Aircraft Carrier - Changes in Portsmouth Harbour

Earlier this week the Deputy Queen’s harbour Master, Gideon Sherwood, talked to a meeting of Gosport NCI (the local Coastwatch station) about the work going on in Portsmouth Harbour in preparation for the arrival of the new aircraft carrier, Queen Elizabeth (provisionally taking place in May 2017). The harbour entrance area is the busiest water space in the UK.

The current dredging activity is going OK, with only about two million cubic metres to go. The channel itself will be dredged to 9.5m for its full width with the main part having 10.5m. The notorious hazard of Hamilton Bank, just outside the Portsmouth channel to the NW of Spit Bank Fort, has already been reduced considerably in height but the plan is to deepen it by a further 4.2m. It is pretty likely that maintenance dredging will be needed at intervals after the current work is finished. Apart from the bulk dredging, fishing for ferrous objects detected by scanning has produced, among other things, a German unexploded bomb as well as the “friendly” torpedo that received good news coverage recently. More alarming was a non-ferrous German “ship-destroyer” mine that was picked up by accident.

The problem is that Queen Elizabeth needs to be on a straight course with only a six-degree margin approaching and passing through the harbour entrance, unlike the current ferries and freighters which can enter on a curving track. These limits mean that during entry or exit the harbour entrance will be closed to both outbound and inbound traffic (including small vessel traffic in the Boat Channel on the West side). Carrier movements are only likely to take place around HW Springs, and entry or exit will not take place if the wind exceeds 20 knots. 

Lots of new navigation marks have turned up over recent months. These mainly provide navigational transits for the carrier’s use.

• The large green pile between 2 Bar and Castle buoys (Castle Pile) provides a transit with the War Memorial.

• The sets of yellow piles in the Bomb Ketch area provide an entrance transit, while the sets in the Spit Bank Fort area provide exit transits.

You will have noticed some changes to buoyage – the movement westward of Outer Spit SC buoy is the most obvious. Most of these changes are temporary while dredging is taking place, but Admiralty charts are corrected very frequently so it would probably not be a good time to buy new charts or update your chart-plotter cards until all this has settled down. However, a permanent R channel buoy named Spit Elbow will be placed between Spit Refuge R and Outer Spit SC buoys.

Details of impending changes will appear in Navigational Warnings and Local Notices to Mariners.

Given the difficulty of entry and exit for the carrier, it may be expected that routine visits will use the anchorage near Stokes Bay, and escort vessels will be picked up at sea.

As might be expected, the MOD police presence on the water will be considerably beefed up, and QHM is getting new and better radar.