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Cape brett tidal streams


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Does anyone know how long before/ after high tide the stream turns north/south at cape brett, and spring/neap speed of the current? And bream head too?

I can't seem to find this info anywhere online and I don't have an almanac handy on the boat I'm on, didn't think to bring it with me from mine. Maybe the info isn't available because there isn't much current to worry about, but I'd like to check as I have to take a slow boat around the cape and would rather be there at the optimum time.

Normally I'd look for a diamond on the chart but only have digital charts on this boat, no paper (shameful I know), can anyone look if there is a diamond please?

Edit: we do have raster charts which show 0.5kn at Brett and 0.3 at bream, there is a diamond at bream but I can't see the data for it.

Thanks!

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Workups from the chart and predicted tide times will only ever get an approximation. It's an NP-hard problem in fluid dynamics and depends on such things as temperature, atmospheric pressure, local winds, freshwater flows into estuaries, far off storms, whether you're vaccinated etc. I learnt a bit about such workups as a volunteer on the Spirit of New Zealand which I highly recommend to everyone. In other words, it's a bit of an art that also involves local knowledge. I'm afraid I don't know what the error margins are.

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There are no tidal diamonds on the charts for Bream Head but the ebb between the Head and the Chicks runs roughly northwards and the flood southwards. Any ships moored in Bream Bay will swing to the tidal flow unless a contrary wind is strong enough. The flows are not that strong until you get to Busby Head at the Whangarei Harbour entrance.

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18 minutes ago, Sail Rock said:

There are no tidal diamonds on the charts for Bream Head but the ebb between the Head and the Chicks runs roughly northwards and the flood southwards. Any ships moored in Bream Bay will swing to the tidal flow unless a contrary wind is strong enough. The flows are not that strong until you get to Busby Head at the Whangarei Harbour entrance.

It's weirdly only on NZ521. And not the 5214 insert, although they left the tide markers....

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All but one coastal I have done -mind I have been awfully close to the Dog at night! And cruising always except once when the seas were so big as we bore away into the bay the little Townson I was on started planing and we held it almost to Albert channel -you dont forget rides like that.

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23 hours ago, ex Elly said:

Tidal diamond B is shown on NZ 5219 Approaches to Marsden Point.

image.png.f5cff0d165123e076e0faa5b5a1e7ced.png

image.png.2597e2dc8209e89ea800abdcf78524f4.png

 

Download here: https://www.linz.govt.nz/sea/charts/paper-charts/nz5219

Can reach over 3 knots!  😲

 

Wow, 3 knots is definitely worth knowing about.

Great info everyone and that's a huge help in passing our passage. Looks like the wind will change by Wednesday and we can get on the way.

It's a real nuisance that they crop the data take for the diamonds off the digital charts, special thanks to those who posted it for both Brett and bream, just what I needed! Next time I'll remember to bring my paper charts!

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24 minutes ago, syohana said:

Wow, 3 knots is definitely worth knowing about.

 

That's at the harbour entrance, pays to try plan that a bit. Bream head not really an issue, does pay to stay out of the stream if its against you once you get around Bream head though.

Cape Brett coming out I all ways go through the gap, unless its a perfect day and I just want to keep sailing off into the distance for a bit.. Going in depends a bit on weather, its usually pretty rolly, the wind goes all round the clock stops and starts.... I usually plan to go wide but often change my mind as I get closer, usually wish I didn't by the time I'm there. Also much nicer with the tide going into the Bay.

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We do need to go out of the entrance first so diamond A is useful. I was planning to depart with the ebb but having the diamond data means I can be a bit more precise about that.

Good advice for brett too, thanks. Long time since I've been up this way. This boat has outboards and likes to pitch, I'll go wide to avoid dunking them under a wave!

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