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Post by Fogg on Dec 8, 2023 15:32:20 GMT 12
How do I see tidal flows on my e-chart at home (Navionics on my iPhone and / or my PC)?
I need to know the tidal flows for tomorrow morning between North Shore and Whangaparaoa Peninsula but can't find a way to see tidal flows (arrows) overlaid onto any of my chart views???
Surely this must be easy and I'm just being numpty?
What am I missing?!
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Post by ComfortZone on Dec 8, 2023 16:26:13 GMT 12
How do I see tidal flows on my e-chart at home (Navionics on my iPhone and / or my PC)? I need to know the tidal flows for tomorrow morning between North Shore and Whangaparaoa Peninsula but can't find a way to see tidal flows (arrows) overlaid onto any of my chart views??? Surely this must be easy and I'm just being numpty? What am I missing?! Not sure how you see them on Navionics, 532 shows .4kts outgoing and 0.5kt incoming in Tiri Channel. Have emailed you some tidal flow diagrams
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Post by muzled on Dec 8, 2023 16:53:03 GMT 12
Use windy?
That has a tide flow thing on it.
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Post by DuckMaster on Dec 8, 2023 17:01:11 GMT 12
Just click the arrow in navionics.
And it displays the tide graph at the bottom.
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Post by Fogg on Dec 8, 2023 18:49:10 GMT 12
The Navionics option only seems to show me tidal flows for Tiri Chl.
I’m looking for more localised flows in particular across the mouth of the Weiti River and a few nm radius out from there.
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Post by DuckMaster on Dec 8, 2023 19:00:56 GMT 12
You can only get them at the tidal spots.
Those are the only places in NZ that are mapped by linz.
The rest are modelled. Only way know of easily accessing the models is the top end predictwind subscription.
There's a group called tidetech but you need special software to view it, like a GRIB viewer for tides... And it's moo beams.
They mapped the Waitamata for the AC.
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Post by fish on Dec 8, 2023 19:07:44 GMT 12
The Navionics option only seems to show me tidal flows for Tiri Chl. I’m looking for more localised flows in particular across the mouth of the Weiti River and a few nm radius out from there. I don't think you will get it. Navionics seems to only do the standard tidal diamonds. Two options. One, Predict wind are now doing a full tidal and ocean currents chart. Down to max res 100m I think. Only issue is you need to pay for it. It's not on the basic subscription, but the 'Standard' and 'Premium' have it. Standard is $250us / year. I'm very keen on tidal flow for a number of things (currently, tyring to find good spots of current over structure for Kingi's), but there is no feckin way I'm risking the missus finding out I spent THAT MUCH on a forecast app. Two, ask someone who's kept their boat up the Weiti for the last 20 yrs... which would be me. I know for sure that on the outgoing tide the tide pushes out (east) down along the peninsular. I believe (but not verified) that on the outgoing tide it flows kind of north ish and east ish from around Piripiri Point (north end of Long Bay). So the water from Okura would flow kind of towards Arkles then out east toward GH. You might get a 0.2 to maybe 0.5 knt push max from this when further away from the river mouth. Within 1-2nm of the river mouth I'd expect this to all flow the opposite way on the flooding tide. I get the impression the area off the cliffs between Arkles and the river have an inflowing current on the flood. At full flood it is normal to get about 1 knot of tide around the bar and further up the channel. 1.5 knts is not unheard of on springs and especially after rain on the outgoing. Current tends to be stronger on the outgoing than the incoming. Exactly where the bar is is a bit hard to explain. There is a bit of a headland, which is outside the green marker post. When you can see the outside cliff face of this you are over the bar. You can see where the deep channel is over the bar when there is a strong outgoing tide, it's where the ripples / waves are. Basically it is in a straight line from the inside green post to the outside port post. On the outgoing I'd expect the strongest east setting current in a band maybe 50m-100m wide, on the north side of the outside port post. Be aware that none of the posts are exactly where they are shown on the charts. The red post I think is further south than shown. The inside green post was destroyed last January and I haven't yet determined what location the new one is compared to the old one, but I think it is further east. Note also Navionics shows to green posts. There is only one. Are you planning one of your hair-brained ocean swims?
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Post by Fogg on Dec 8, 2023 19:24:46 GMT 12
Yeah thanks that v useful, fish.
And also the tide charts that Comfortzone just sent me - they basically align with your observations.
And yes I’m planning on doing a swim tomorrow morning across from Long Bay to somewhere on the south side of the peninsula - anywhere between Arkles Bay in the west to GH in the E. depending how I feel. At this stage I’m picking Little Manly as my most likely landing point as it’s the first long one for a while.
And given its high around 5am then I should seeing some helpful tidal benefits between around 7-9am which is my window.
Perfect!
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Post by sloopjohnb on Dec 8, 2023 19:52:41 GMT 12
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Post by fish on Dec 8, 2023 19:53:05 GMT 12
Yeah thanks that v useful, fish. And also the tide charts that Comfortzone just sent me - they basically align with your observations. And yes I’m planning on doing a swim tomorrow morning across from Long Bay to somewhere on the south side of the peninsula - anywhere between Arkles Bay in the west to GH in the E. depending how I feel. At this stage I’m picking Little Manly as my most likely landing point as it’s the first long one for a while. And given its high around 5am then I should seeing some helpful tidal benefits between around 7-9am which is my window. Perfect! Be careful of jetski's in the marine reserve. When it is a mint glassy calm sunny day (like tomorrow is forecast), they like to send it from Arkles over to the Marine reserve / towards Okura etc, do donuts or whatever the feck it is jetski's do, them zoom off again. Noting that 7-9 am is probably too early for them. And there is likely to be fisho's around the edge of the reserve, but nothing new there. PS, What are CZ's tidal charts? Something better than LINZ stuff?
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Post by sloopjohnb on Dec 8, 2023 19:53:23 GMT 12
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Post by sloopjohnb on Dec 8, 2023 19:53:59 GMT 12
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Post by sloopjohnb on Dec 8, 2023 19:56:04 GMT 12
As you can see I am old school.........none of this electronic stuff
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Post by fish on Dec 8, 2023 19:56:48 GMT 12
That is great SJB, thanks. I used to use tide charts like these for the UK, English Channel all the time. You'd keep them with your chart and dividers. Never knew they were available for the Gulf. I figured the tidal streams weren't strong enough here for people to really worry about.
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Post by Fogg on Dec 8, 2023 20:00:49 GMT 12
I just assumed that anywhere that had been well charted by hydrographers included capturing the coastal tidal flows. Hence my surprise not to find this easily.
There’s no way I’d swim out there unaccompanied due to risk of collision - so I’ll have a support boat nearby.
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