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Tidal flow data on north island NE coast


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I'm starting to think about tactics etc for the coastal classic. I'd like some tidal flow info for the coast from Auckland to BOI.

I've got this info (chart for each hour after high water etc) for cook strait, but surely there is something similar for this area? Who's got something?

Also interested in general comments from those who have done this race before ( I haven't)...

Thx

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On the Spirit of NZ, it's the morning job of the cadet under supervision of the Third Mate to calculate daily tidal flows for where the ship will be. I'm sure they'd be happy to share the recipe and adjustments they may make for deviations from predictions. And I'm sure you know about the occasional tidal flow notations on the paper charts. I'm assuming ECDIS systems have the same?

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What you really need to know is what's happening with the warm current that runs down the east coast.

It's often close to cape Brett then runs outside the Hen & Chicks then outside the Mokes then kicks south at the needles

The catch is sometimes it runs inside the H&Cs and therefore speeds up so that makes going outside beneficial, but rarely it runs the other way ie south to north.

It's usually not that fast at this time of year but speeds up as the warm currents come out of the pacific

The other major area of concern is tidal flow at bream head

Other than that sail north and turn left at the Cape, but inside or out of Piercy Is ?

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As far as Auckland tides go, the thing to remember is that the 'sink hole' is actually the firth of Thames not Auckland harbour so the incoming and outgoing tide is relative to that rather than Auckland harbour itself. Therefore the current in Tamaki strait runs the oposite to what you think, ie outgoing tide has current running towards Auckland and incoming tide it runs away from Auckland.

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Not all of them khayyam, only the first 5 hours after high water Auckland. Do you have the whole set?

Thats what i'm looking for...

Tidal atlas for the Hauraki Gulf and Greater Cook Straight, ed: R Garrett. I also only have high tide to high tide + 5. I think the idea is to reverse the charts for the incoming cycle? 

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Tidal atlas for the Hauraki Gulf and Greater Cook Straight, ed: R Garrett. I also only have high tide to high tide + 5. I think the idea is to reverse the charts for the incoming cycle? 

Yeah, I thought about that. I know the ones for cook strait are not reversals though....

 

Attached is what I have for Hauraki Gulf

Tide Maps Hauraki.pdf

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These two websites have free ocean current models:

https://www.windytv.com/?currents,2016-10-15-21,-35.299,174.375,8

https://windria.net/auckland-nz  (click on the "currents" tab)

 

Not sure how reliable they are?? particularly as one gets closer to east coast, but interesting to study.

 

General NZ current diagram - http://calib.qub.ac.uk/marine/currents/NewZealand.html 

 

I have observed southerly current approaching 1/2 kt between brett and poor knights. I suspect Jon is right about east auckalnd current not being as strong this time of year. 

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I have seen yachts (with I suspect, local knowledge) sailing North between Whangaruru and Cape Brett curve in towards Whangamumu before reversing the curve as they neared the peninsular, heading out to Cape Brett. They literally sailed away from us, we were headed directly for Cape Brett, I didn't check, but it would suggest that the tidal flow was southerly and there is an eddy that rotates inshore of the Cape.

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I have seen yachts (with I suspect, local knowledge) sailing North between Whangaruru and Cape Brett curve in towards Whangamumu before reversing the curve as they neared the peninsular, heading out to Cape Brett. They literally sailed away from us, we were headed directly for Cape Brett, I didn't check, but it would suggest that the tidal flow was southerly and there is an eddy that rotates inshore of the Cape.

Most likely Steve

But don't stay in too long or you will fall into the wind shadow between Whangamumu and the Cape

 

"Shot the gap" or 'round the out side like a buffalo girl' ?????  

That's the real question, I've always gone through and said next time I'm going around ????

"The definition of insanity is to keep doing the same thing but expect a different result"

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Most likely Steve

But don't stay in too long or you will fall into the wind shadow between Whangamumu and the Cape

 

"Shot the gap" or 'round the out side like a buffalo girl' ?????  

That's the real question, I've always gone through and said next time I'm going around ????

"The definition of insanity is to keep doing the same thing but expect a different result"

Went around last time the Marshall did it and got killed... Good luck!! 

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Haven't you lot figured it out yet - it works like this

The guy in front will go round - and get it right

The guy behind will go through - and also get it right

It doesn't matter which way you go - you're guaranteed to f**k it up!

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Here's a tip for the next time you are crossing Bream Bay: check the direction of any anchored ships. They normally lie to the current except around the slack with a strong wind.

The current at either end of the Hen and Chicks is generally Northwards on the ebb and southwards on the flood.

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