Currents at Slack Tide

[SteveK]

I think I know exactly what he meant.....no confusion on my part.

Deep waters (generally) but strong currents and whirlpools in the PNW and shallows and tidal currents that are not that big of a deal east.

I still don't get the confusion most of the time...but yes there are times a word or combo of words might give the wrong impression.

And yes..that's why I often use the word "depends" as so many of us experience thing in different ways and environments as boaters. Those that have boated many different areas and ways probably pick up that a bit faster.

depends, here all this time I thought you meant ......... never mind

 

[DDW]

Predicted Log contestants use NOAA current predictions. After twenty odd years of competing, I have found the NOAA predictions to be close, but no cigar.

On the mid BC coast and SE Alaska, the NOAA current predictions seem to be a long way off, and often a complete a fantasy. The tide predictions are closer.

The delay of current relative to tide isn't just the momentum of the water, it is also the relative heights of the bodies involved. At the mouth of an inlet, the height may begin to drop, but the confined body well beyond has not reached that height yet so the current will continue to flood even though the tide is falling and the mouth.

Sometimes the current is just perverse, such as in the Baronet passage in the Braughtons which runs the opposite of everything around it. I imagine some complex modeling might predict that, but observation of a chart would make you believe it impossible. There are other places where the tidal current always runs one way, though that would seem impossible.

 

[Moonfish]

Then you currently stand corrected?
Ok I'll cut you some slack.

 

[Alaskan Sea-Duction]

Lets see if I get this:

The current direction also depends on location. Take Dods Narrows. The incoming tide comes around Vancouver Island. So as the tide is increasing in highth, the current increases from the south. When the tide is outgoing, and decreasing in highth, the current switches and flows from the north.

Note: the two currents around Vancouver Island has little change where the two tides meet somewhere in Desolation Sound.

 

[tadhana]

Where I learned to sail on an island off the cost of MA the current goes slack at the time of high and low water. I sure was in for a surprise when i moved to the Chesapeake! In an estuary the time of high water or "high tide" does not coincide with slack current, or "slack water." On the Chesapeake the offset is almost 3 hours. Maximum ebb current is at the time of low tide. "ebb slack" is about the time the tide is about half way up. Maximum flood current is about at the time of high tide. "Flood slack" is when the tide level is about half way to low tide. In
the Hudson river the time of the offset changes as you move up the river. Entering any of the east coast inlets you can be pretty sure that the time of maximum ebb current will be near the time of low tide +/- an hour or so.

Note in the attached file the graphics department added a few arrows in the first diagram which are incorrect. But the rest of it is OK.
Thishttps://www.dropbox.com/s/z3ktfrtqjpgia5e/cbm092016%20the%20bays%20ups%20and%20downs.pdf?dl=0

 

[johnma]

I have an app on my phone "tides near me". it is a free app and has high and low tide times plus times for last current-slack; next current-ebb and following current -slack. Boating in an area with a 7-8' tide range and an inlet I cant get through at low tide i never leave without knowing tide and current. The inlet is 40' wide with rocks on one side and the current when moving is 90 degrees to the inlet.
John

 

[rsn48]

Knowing high and tide times in some areas here in PNW, BC & AK won't help you by themselves with slack. You have to know the correction from the low and high to get slack. This is easy to do in these waters as you can take it from the Canadian Tide and Current tables and a well known book calls "Ports and Passes." In fact yesterday, I just went out and bought Vol 5 & 6 for the Tides and Current tables and 2020's Ports and Passes.

 

[klee wyck]

From post 25 for example on today from my tide/current app (not chart)

Low tide near Hole in the wall today was at 2:58 PM. If you arrived there at that time today expecting flat water you would have found that slack occurred nearly an hour and twenty minutes before and would have been facing a flood of nearly 5 knots on the way to eight knots within the hour. And that tidal swing today was only 8 feet. It will be 12 feet next Saturday.....

 

[BruceK]

Not sure why someone thinks what I have posted is wrong?

At last The Pope has competition on infallibility.

 

[psneeld]

Not my intent..... I like to be accurate when I give advice and did not see what I had posted that was incorrect.

I never did get an answer that I saw pointing out what I had posted was wrong.

Just like the post where C M S showed me why regs were applicable on shore power amperage, I said thank you and moved on. Funny how many times I have done that and it seems to get missed.