MARICO Marine NZ Limited WELLINGTON HARBOUR PORT AND ...

Report No: 05NZ104 WELLINGTON HARBOUR
Issue: Issue 1.1 Operational Risk Assessment
5.2 AREA A - APPROACHES
This area represents the coastal margin of the Wellington Harbour Limits,
the harbour approaches and outer boarding areas. The area is
geographically part of Cook Strait where weather and sea conditions
frequently present adverse conditions for all navigation categories, with
potential for heavy seas, strong winds and tidal flows.
The navigational use of Area A is primarily for transit to and from the inner
harbour areas. However, leisure use is also significant, as are fishing
activities.
5.2.1 Area A - Physical Description
The approaches to Wellington are relatively straightforward, when compared
with some other New Zealand ports, with a bold coastline either side of the
entrance providing good radar echoes (although the NZ Pilot cautions
mariners that the high terrain inland of Baring Head can give a similar
picture to the actual coastline and misinterpretation of position).
The coast to the east is generally free of outlying dangers with the exception
of Arabella Rock, 0.4 miles West of Baring Head at 4.4 metres depth.
Another rock lies at 8 metres depth, 3 cables South West of Pencarrow Head.
As these dangers are respectively only 1.4 miles and approximately 3 cables
from the nearest Pilot Boarding Area or line of the leads, there is not a
significant margin of safety for boarding pilots if things go wrong.
To the west of the entrance the coast is indented with several bays and
outlying dangers such as West Ledge, a reef extending 0.5 miles out from
Palmer Head. There are many sunken rocks throughout. These dangers are
located in areas outside normal trading vessel routes, but are relevant to
small and leisure craft, making local knowledge vital for navigating close to
shore.
Depth of water is in excess of 30 metres is until approximately one mile
south of the entrance. At this point the sea floor shelves relatively steeply to
between 14 and 16 metres at the harbour entrance. Swell from the
southerly quarter tends to become attenuated as it approaches the entrance
with decrease of wavelength and increase in steepness as the coast is
approached. The height and period of swell can change significantly in a
short time as can be appreciated from Figure 6.
Greater Wellington Regional Council /
CentrePort Ltd Page 25 of 102