Cook Strait

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Cook Strait
41°13.800'S, 174°29.000'E Chart icon.png
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The Passage

Description

You should provide a map of the of the passage with the route clearly shown. The map should be preferably well annotated and with a scale in nM (nautical miles). Place the map to the right .

Cook Strait is a natural wind funnel bordered by high geographic features on the North and South Islands of New Zealand, and at times creates a formidable gauntlet for boats sailing to and from the South Island. The following information is provided to help you cross the Strait safely.

Cook Strait is a formidable piece of water with changeable weather and a number of natural hazards. In addition it is a busy traffic area. As well as the local ferries, many ships cut through the strait to avoid going round the top of the North, or bottom of the South Islands.

Study the relevant charts before your attempt the crossing and carefully read the instructions below. If you're not confident don't hesitate to contact one of the local yacht Clubs for someone to help crew. Many local yachties have made dozens of strait crossings and enjoy the trip.

Be especially careful of your departure time because with tide (and perhaps wind) against you, it can be very difficult to gain ground. Currents in the strait run as quickly as 6 knots in places.

Ensure that all crew wear their life jackets whilst in the Strait, and if going out on deck fasten to a jack stay. This is not a place to fall overboard. Given the nature and length of the trip it also pays to have pre-prepared some hot drinks and food. Fruit cake is the writers preference! Also have wet weather gear and woollens handy even if it is a fine day. Cook Strait can become very cold and wet very quickly.

The nature of the seas in the strait is typically rougher than most other passages. So sea sickness can be an issue. Again try to prepare ahead.

Charts

Land Information NZ
NZ46 Cook Strait (1:200000)
NZ48 – Western Approaches to Cook Strait
NZ463 – Approaches to Wellington Harbour (1:100000)
NZ615 – Marlborough Sounds (1:100000)
NZ6151 – Plans in the Marlborough Sounds (scale varies on each chartlet)
NZ6152 – Pelorus Sound & Havelock (1:50000)
NZ6153 – Queen Charlotte Sound (1:36000)
NZ6154 – Tory Channel Entrance & Picton Harbour (scale varies on each chartlet)

(The above list assumes you'll be visiting the Marlborough Sounds)

Weather

Wind direction in Cook Strait is normally NW or S to SE. Storm force winds occur on average about 25 times a year. Gale force NW winds are usually very localised, but S gales affect the whole Strait. SE gales are more pronounced on the western side of the Strait.

Sea breeze conditions, with day and night winds alternating in direction, do not happen as a matter of course in settled weather in the Cook Strait region.

See also New Zealand with the same caveats listed there as to the accuracy of NZ weather forecasts. Note that in a 2013 trip through the Cook Strait over a period of 3 days I found that the NZ Met Service forecast was not correct at any time during those 3 days in terms of either wind strength or wind direction, and anecdotal evidence seems to indicate that this is fairly common -- Delatbabel

Sources for weather information:

Currents & Tides

Tidal streams in Cook Strait generally flow towards the NW for 5 hours and SE for 7 hours. However, they are unreliable and the surface currents are affected by prolonged periods of strong winds and the shoreline configuration which can cause counter currents if close inshore.

High water occurs on the western side of Cook Strait about 4 hours later than Wellington at spring tides and slightly less at neap tides. This difference causes the strong streams. The streams are stronger during spring tides, which occur at two weekly intervals, when high water Wellington is about 0600 and 1800.

Tidal stream predications for Tory Channel have generally been found to be very accurate.

Sea State

Broken water is experienced in different parts of the Strait. This is caused by the cold north-setting bottom current being forced to the surface on meeting the steep slopes of submarine canyons, which will also cause modification of the tidal stream. Broken water is also caused when the wind flow is against the tidal stream, especially between Sinclair Head and Cape Terawhiti, off the eastern entrance of Tory Channel, and in the vicinity of the Brothers Islands.

Fog

Fog is rarely found in the Cook Strait area as the wind funnel effect sweeps it away. Late Summer is usually the only time of year fog is experienced. Low cloud and rain though can severely restrict visibility.

Weather Windows

Many people agree that the tail end of a southerly gale is one of the best times to cross Cook Strait. This period of light weather often lasts for 24 hours.

Navigation

Offshore Hazards

Awash Rock

Lying almost midway between Perano Head and the Brothers Islands, approximately 2 nm offshore, the rock, as its name so rightly suggests is a rock to be avoided.

Fisherman’s Rock

Lying almost midway between Cape Koamaru and Mana Island it has a clearance of 10 metres. However the area surrounding the rock can be hazardous in strong tide or wind conditions. Large overfalls and seas can develop in these conditions.

Thoms Rock

Situated between Karori Rock and Sinclair Head. It lies 0.5 miles offshore. See passage instructions below.

Cook Rock

Situated 4nm north east of Cape Koamaru, the rock is visible in calm seas

The Brothers Islands

Formed by 2 small islands 2 1/2 miles east of Cape Koamaru. There is a lighthouse on the northern island visible 19M with a red sector light visible 10M. The water between and around the area of Cape Koamaru and The Brothers is often surrounded by overfalls, whirlpools and currents. Avoid the temptation to passage between the two islands except in calm weather. It's often wise when in this area to have your motor idling in neutral, even with good winds.

Whales

With whaling having been banned in New Zealand since the early 1960s whale populations have been on the rise. Cook Strait is a migration path for several species. So keep a careful watch. Humpback whales in particular seem to always feel that they have the right of way.

Tory Channel Entrance

Tory Channel

The entrance to Tory Channel can be a maelstrom of white water when the current is flowing out against the wind or currents in the Strait itself. The writer's preference has usually been to avoid Tory Channel and both enter and exit the Sounds via Queen Charlotte Sound. This usually adds very little time to the trip and often it ends up being quicker with a favourable wind.

As an aside when returning to Wellington, exiting from Queen Charlotte Sound also offers the option to head directly to Mana rather than Wellington. That's not to say that we don't wish to end up in Wellington, but on the odd occasion the writer has sailed out of Queen Charlotte Sound, past the Brothers Islands to find that the weather forecasters have made a mistake. So rather than beat for hours into a nasty southerly wind and chop, we've shaped a course to Mana (beam reach), where we've spent a day or 3 or 4 on the visitors berth waiting for a favourable northerly to take us home to Wellington.

Cray Fish Nets

To the east on Sinclair Head and to the south of Tory Channel entrance keep a good watch for cray fish net buoys.

Tory Channel Transit

The following is a paraphrase of the Notice to Mariners issued in August 2007 regarding vessels passaging through Tory Channel:

All ships transiting Tory Channel, operating at a speed of less than 15 knots shall broadcast to ALL SHIPS based on the following criteria:

For Inward Bound Vessels

When on an arc of 3 nautical miles to seaward of East Head Light make a broadcast on Channel 19 VHF advising of the intention to transit Tory Channel inward bound and providing that the ETA at the Controlled Navigational Zone boundary as well as at East Head at the ships anticipated speed. Subsequent broadcasts, confirming or amending ETA is to be made at intervals not exceeding 10 minutes.

For Outward Bound Vessels

When abeam of Te Uira - Karapa (Clay Point) East Light, make a broadcast on Channel 19 VHF advising all ships of the intention to transit Tory Channel outward bound and providing the ETA at the controlled Navigation Zone boundary as well as East Head, at the ship's anticipated speed. Subsequent broadcasts, confirming or amending ETA is to be made at intervals not exceeding 10 minutes.

Notes

The above broadcasts may be repeated on Channel 16 VHF

Any significant changes in ETA must be promulgated to all ships.

The Controlled Navigational Zone boundary is marked on LINZ and Navy charts NZ 615, NZ 6153 and NZ 6154 .

For all ships operating at speeds greater than 15 knots, the provision as set out in the Marlborough District Council Navigational Bylaws 2002 Part3.3 (iii) shall apply. Masters of such vessels must know these regulations.


Communication

Also see World Cruiser's Nets.

Cook Strait Crossing Trip Report

The objective of a TR is to tell an authority where you are going and when you expect to arrive, so that if something goes wrong you will be helped.

In Wellington and in Cook Strait, reports should be filed with Wellington Maritime Radio. Why? Apart from the fact they are the prescribed authority, they also have very powerful transmitters and very good ears. This means that if you need help they are likely to be listening.

Don’t use Beacon Hill. They are busy enough with harbour traffic. They will hear and possibly log your TR, but that is not their duty. They are the harbour radio. At night, separately from your TR, log your movements in and out of the harbour entrance with Beacon Hill. That is required and will get a response from them telling you of other movements. They will also tell others of your movements.

Important Note In addition to a TR you should always leave details of your trip (a 2 or 10 minute form is good for this) with someone. Neither Wellington nor Marlborough Sounds Radio follows up that a TR is closed with a safe arrival.

How To Do A Trip Report

Select Channel 16. Listen to make sure the channel is not being used. Speak slowly and clearly. There is no rush. Channel 16 is normally a quiet and calm channel.

Say: Wellington Maritime Radio, Wellington Maritime Radio, Wellington Maritime Radio (3 times gives them time to get ready to note your call). This is (boat, boat, boat) (3 times) call sign, with a TR.

Wellington Maritime will respond with: Boat, this is Wellington Maritime please go to Channel 71 (they might ask you to use 68. They know from your call where you are and which channel to use).

Your response is: Going Channel 71. Change to Channel 71 and call: Wellington Maritime (boat). They will respond: Go ahead please (boat).

You then reply: Wellington Maritime this is (boat) departing Wellington for Tory Channel ETA x hours. We have x adults and x children on board. It is not necessary to give the adult /child breakdown, but if you do, in a rescue situation they will know what they are dealing with.

The response from Wellington Maritime will be: (Boat) this is Wellington Maritime, that is all logged thank you, or some other request.

Your reply is to confirm their response with something like: Thank you Wellington Maritime this is (boat) listening 16, over.

If you decide to stop and go fishing, or your trip is taking longer than expected, you must call on Channel 16 again and update them with your new arrival time, or abandonment if you turned back.

At the end of the trip the format is similar to departure and you can save some of the channel changing if you call Wellington Maritime on 16 and say, very slowly and clearly: Wellington Maritime (3 times) this is (boat)(3 times), call sign, with an arrival TR.

They will normally respond with something like: (Boat) this is Wellington Maritime, that’s all received, have a good day.

Your response is: thank you for listening, this is (boat) listening 16.

Don’t try to call Maritime Radio on Channel 71 or 62. They listen for 16. Neither they, nor any of the other authorities, formally monitor those other channels, although they might be listening at times. Also, Channel 16 is normally quiet, so if you or anyone else makes a mayday call or a TR report, it is likely to be heard. It is comforting to know there is another boat out there. You can hear the other boats if they are close, you will only hear Maritime Radio if they are not. Wellington Maritime is very professional. They know the who, why and where and are quickly in touch with authorities.

Possible Departure Points

List the possible departure ports. Include their coordinates. It is assumed that corresponding Wiki pages of these ports either exist or will be created.

  • Departure Point1/wiki/Cook_Strait#.3Cspan_style.3D.22color:magenta_.22.3EDeparture_Point1.3C.2Fspan.3EMarina icon Departure Point1 [[Cook Strait#Departure Point1|Departure Point1]] DD°N.m′N/S, DD°M.m′E/W
  • Departure Point2/wiki/Cook_Strait#.3Cspan_style.3D.22color:magenta_.22.3EDeparture_Point2.3C.2Fspan.3EHarbour icon Departure Point2 [[Cook Strait#Departure Point2|Departure Point2]] (Alternate name Departure Point2) °'N, °'E
  • Departure Point2/wiki/Cook_Strait#.3Cspan_style.3D.22color:magenta_.22.3EDeparture_Point2.3C.2Fspan.3EAnchorage icon Departure Point2 [[Cook Strait#Departure Point2|Departure Point2]] (Alternate name Departure Point2) °'N, °'E
  • etc.

Route/Suggested Stopovers

Passage Wellington to/from Tory Channel (or Queen Charlotte Sound)

The combination of broken water and strong wind gusts between Sinclair Head and Cape Terawhiti make it advisable to transit this section of the passage (commonly known as The Rip) at slack water. This section of your voyage is generally the most uncomfortable and should not be attempted by small craft or the inexperienced except in favourable conditions. Without local knowledge a minimum clearance from the shore of one mile is necessary and two to three miles are more prudent. Strong southerly winds with a SE setting tidal stream can make this area a real horror show, and in the interests of safe boating and harmonious crew relations, should be avoided.

Travelling Westbound

Leave Wellington to arrive at Sinclair Head 1 hour before HW Wellington. You will then have a favourable tidal stream across Cook Strait.

Alternatively, leave Wellington to arrive at Sinclair Head 1 hour before LW Wellington. You will then have an adverse tidal stream across Cook Strait, but in northerly winds this may be preferable. Tory Channel will be reached at slack water.

Travelling Eastbound

Leave Tory Channel 2 hours after the tidal stream commences setting E. You will have a favourable tidal stream across Cook Strait-and through the Cape Terawhiti-Sinclair Head area.

Alternatively, in southerly winds leave Tory Channel as the tidal stream starts setting W. You will have an adverse tidal stream across Cook Strait, but this may be preferable in southerly winds. The Cape Terawhiti-Sinclair Head area will be reached at slack water.

Clearing Marks

Thoms Rock Situated between Karori Rock and Sinclair Head. It lies 0.35 miles (650 metres) outside a line joining these points. Rock hopping in this area is not advisable.

Day: Keep Pencarrow Lighthouse visible through Sinclair Head until Karori Rock is open from Cape Koamaru. Night: Keep Pencarrow Light visible (red or white) until Tongue Point Light changes from red to white.

Sinclair Head Day: To pass about one mile off Sinclair Head, keep Pencarrow Lighthouse (lower) and Old Lighthouse (upper) in line. Night: Keep in the white sector of Pencarrow Light to pass 0.7 miles off Sinclair Head.

Checking on Tidal Set Day: Observe Karori Rock relative to Sinclair Head or Turakirae Head. Observe Tory Channel entrance relative to Mount Stokes. Night: Observe Tory Channel Entrance Leading Lights.

Possible Arrival Points

List the possible arrival ports (in sequence). Include their coordinates.

  • Arrival Port1/wiki/Cook_Strait#.3Cspan_style.3D.22color:magenta_.22.3EArrival_Port1.3C.2Fspan.3EHarbour icon Arrival Port1 [[Cook Strait#Arrival Port1|Arrival Port1]] DD°N.m′N/S, DD°M.m′E/W
  • Arrival Ports/wiki/Cook_Strait#.3Cspan_style.3D.22color:magenta_.22.3EArrival_Ports.3C.2Fspan.3EHarbour icon Arrival Ports [[Cook Strait#Arrival Ports|Arrival Ports]] DD°N.m′N/S, DD°M.m′E/W
  • etc.

Distance & Duration

  • Distance = 50 nm from Wellington to Tory Channel entrance
  • Duration = 8-10 hours for most yachts

Passage Mana to/from Queen Charlotte Sound

Usually a much more pleasant trip than that described above for Wellington to the Sounds. The sail across from either direction is almost always on a beam reach given the prevailing winds. And the more northerly course than above also means that the passage avoids most of the frustrating rips and tidal streams.

  • Distance = 25 nm from Mana to Queen Charlotte Sound entrance
  • Duration = 4-5 hours for most yachts

See Also

Friends

Contact details of "Cruiser's Friends" that can be contacted for local information or assistance.

Forums

List links to discussion threads on partnering forums. ('see link for requirements')

  • www.crew.org.nz (select Welly thread)

Links

References

If you're intending to spend some time in the sounds, (and what's the point of coming this far south if you're not?) then buy, beg, borrow or steal a copy of New Zealand Cruising Guide - Central Area by Keith Murray (SV Rose) and Baron Ralph von Kohorn. It is ISBN 0-9597848-5-3 and published by Steven William Publications, PO Box 491, Wellington. It's available from most local boating shops.

Comments

We welcome users' contributions to the Wiki. Please click on Comments to view other users' comments, add your own personal experiences or recommend any changes to this page following your visit.

  • Grantmc, the writer of this page has made quite a number of crossings in both daylight and at night, some in atrocious weather conditions. On several occasions it has been like having someone pour a bucket of sea water over my head every few minutes (no fun). And I confess to always having butterflies before leaving. It is both excitement and nervousness; what will the strait be like? But most crossings are fair weather affairs, a number have been wonderful sails under spinnaker. Also it's not been unusual to find one has had to motor the entire way because there's been not even a zephyr (I actually find those crossings the most frustrating).
    A wonderful privilege too has been the incredible displays of wild life. We've seen several varieties of whale and are often escorted by dolphins (yes I know they are also a species of whale). A wide variety of birds have been seen, and also occasional seals. And you know the fishing in the Strait is pretty good. Even just hanging a line out the back as you go along you're bound to catch some good sized kahawhai.

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Date of member's last visit to Cook Strait and this page's details validated:


This is a usable page of the cruising guide. However, please contribute if you can to help it grow further. Click on Comments to add your personal notes on this page or to discuss its contents. Alternatively, if you feel confident to edit the page, click on the edit tab at the top and enter your changes directly.


SailorSmiley.gifContributors to this page

Names: Haiqu, Grantmc, Delatbabel


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