Canadian Current Atlas Options

[Marlin Prowell]

If you sail in the Pacific Northwest, you are undoubtably familiar with the Canadian Current Atlas. The cover is below, and is full of 93 map pages full of arrows, all slightly different. Map 4 is pictured below.



The Canadian Current Atlas preamble contains 4 pages that explain how to calculate the correct map to use for every hour of a day. Nobody I know does the calculations. Instead they buy a pamphlet each year that has each hour calculated and listed in a table. The pamphlet used to be called Washburne's Tables, but is now titled Waggoner Tables. The table for July 2023 is shown below.



You look up the day you are going sailing and find the numbers of the maps, hour by hour, for that day. You then start looking through those maps, comparing all the maps for the day to see when would be the best time, current wise, for you to leave. A little tedious, but better than performing lots of calculations to find the correct map numbers. I bought the Washburne's Tables pamphlet for many years.

But you don't have to buy a new Waggoner Tables pamphlet each year. A few years ago I found a free on-line source for the current atlas tables. Emanuel Borsboom provides a set of tables, free for non-commercial use. He wrote some scripts that do the calculations and created a PDF of the monthly tables for each year. You can find his tables for the next eight years here.

Times have changed and paper charts are no longer readily available. So, too, with the Canadian Current Atlas. The atlas is no longer in print. Instead the Canadian government provides a PDF of the Canadian Current Atlas. It is Volume 3 on this web page.

Now checking currents has become awkward. First you find the desired map number on a page of the tables PDF, then find the map itself in the atlas PDF. Of course the map numbers in the atlas PDF do not match the PDF page number, so hunting for the wanted map is necessary. This should be easier.

A small software firm has done just that. You can now get an iOS or Android app that has all the current maps preloaded on your phone or tablet. You can look up any date and time to see the corresponding map. Best of all, there are forward and backward arrows to step forward and backward in time, one map at a time. Seeing the current changes from hour to hour is now immediately obvious. The app is called Current Atlas sold by Tiny Octopus and a tablet screen shot is shown below.


Checking the currents for your next trip could not be easier!

 

[Loren Beach]

Being a bifocals wearer, I find the page size in the index booklet a tad small, so I scanned the pages for (our planned) summer cruising. Then upsized them. Then printed them out, full page size.
My plotter does display rudimentary tide arrows on the charting, but it's like a truncated version.
Love the analog way to quickly see where the currents are stronger or weaker, hour by hour. No batteries needed!

 

[Marlin Prowell]

I saw someone using the Canadian Current Atlas with the Waggoner book at the Rendezvous, determining when to head out. I agree, the Waggoner book is too small. I showed him the Borsboom PDF link and also the Current Atlas phone/tablet app. In my post above, the current atlas lookup table page next to the Waggoner Table cover page is actually from Borsboom’s PDF, not from the Waggoner book. Each month prints as a full size 8.5” x 11” page and is much more readable. I print a sailing season’s worth of pages and store them in a clear plastic sleeve in the nav table.

 

[Tomfoolery]

I’ve been using the app on my Apple products for a couple seasons, very convenient!

 

[bgary]

I carry - and use - the tables and the current atlas. But if one has cell/internet connectivity, there's also a website (deepzoom.com) that basically does an animation of the same information. You pick a day, and using a slider can see what the currents are doing at different times of day. Very slick, plus you can zoom in on areas and (e.g.) see the details around Shaw Island.

Real-life example, on Sunday I used it to find the sweet spot in the day where there would be enough ebb to take me down the San Juan Channel and out Cattle Pass, and 4 hours later have a healthy flood to sweep me into the Admiralty Inlet. Takes just a minute on DeepZoom, where it would involve some flipping back and forth between tables and current-atlas pages to narrow down the same info.

 

[southofvictor]

I like the way the current atlas shows all the eddies, I wish there was one with that much detail for Puget Sound!

 

[bgary]

I like the way the current atlas shows all the eddies,

Very true! First time I went up to Genoa Bay, my current planning had me facing a pretty stiff ebb all the way up Haro Strait. Ugh. Didn't like any of the options. But in looking more closely at the current atlas, it seems that - at times - even when the ebb is going strong, there's a little counter-current right inshore along the west edge of San Juan Island.



Sure enough, got within a half-mile or so of San Juan Island's shoreline, and there was a handy little counter-current that carried me straight toward Sidney. Made for a much more pleasant day without having to buck the ebb..

I wish there was one with that much detail for Puget Sound.

There is, sort of. There's a volume that NOAA published in 1973 (!) that shows the current patterns in Puget Sound. Not as detailed as the Canadian current atlas, but way better than nothing.



The only quibble I have with it is that it keys off of current-state at Bush point (e.g. "this is what the currents look like an hour after max-ebb at Bush Point", etc)... and none of the common tide/current tables seem to include Bush Point as a reference station any more, so you have to go to NOAA's current-prediction tables to figure out when max-ebb and max-flood occur at Bush Point on the days you're interested in.

You can buy a printed/bound copy from Amazon or other sources..

Amazon.com: Tidal Currents of Puget Sound: Graphic Current Charts and Flow Patterns eBook : National Ocean Service, NOAA, Sea Grant Program, Washington State, Burch, David: Kindle Store

Buy Tidal Currents of Puget Sound: Graphic Current Charts and Flow Patterns: Read Kindle Store Reviews - Amazon.com

www.amazon.com

Or you can download a copy from NOAA (it is in two PDF files, one for Puget Sound / northern part, the other for Puget Sound / southern part) Here's the download page for the northern part...

https://repository.library.noaa.gov/view/noaa/23634

....and, here's a link to the NOAA current-predictions page for Bush Point

NOAA Current Predictions - Current Predictions

NOAA Current Predictions

tidesandcurrents.noaa.gov

B

 

[southofvictor]

Awesome, thanks for that Bruce!