Tide times the same = no current ?

[Dave_S]

A question was asked on Facebook which way does the tidal current run between two points along the Queensland coast about 50nm apart (Double Island Point and Mooloolaba) looking at the tide time tables between the two and they are almost the same and similar-ish in Longitudes.

Does that mean there will be almost no current apart from in and out of inlets ?

Is this because this is so far from the cape that it has almost no effect and the further north the more tidal currents increase.

I must confess I don't even consider tidal currents except if I go through the Broadwater to the Gold Coast and then it doesn't change my planning its just for interest sake.

[Alan Mighty]

Originally Posted by Dave_S

A question was asked on Facebook which way does the tidal current run between two points along the Queensland coast about 50nm apart (Double Island Point and Mooloolaba) looking at the tide time tables between the two and they are almost the same and similar-ish in Longitudes.

Does that mean there will be almost no current apart from in and out of inlets ?

Something wrong here, Dave.

The easy answer is that:

1. on the southern section of the Queensland coast, which includes the coast from Double Island Point to Mooloolaba, the flood tide sets to the south (so a south-running current along the coast in the time span between low water and high water) and the ebb tide sets to the north (a north-running current from high water to low water).

2. that reversing current should be, after weather factors, a major (or THE major) consideration in passage planning along the Qld coast.

3. The East Australian current is a significant factor in passage planning in certain parts (not all parts and not all the time) of the southern Qld coast.

4. The Queensland state government operates waverider buoys, some of which give set (the direction in which the current is travelling) and drift (the speed of the water movement). You can access the data from: https://www.qld.gov.au/environment/c...ch/waves-sites

You'll also find other websites, such as https://www.ausmarinescience.com/tid...ater-currents/ , with some waverider buoy data. A couple of those other sites, such at the ausmarinescience site, present the set and drift data in ways that separate that data from wave data and so are more useful at revealing the set and drift story.

[Dave_S]

Thanks Alan

Great information as usual.

Interesting read, looking at the variation in median wave heights to max height. Around 4am this morning median at 1.2 and max at 3.2, that would wake you up!

Also the current and direction chart for NE of North Straddle as you described currently, but earlier this week all South, I assume this is the East Coast Current coming in close to the coast, then moving back out.