How to Predict Current Direction in Swinomish Channel

    What direction does Swinomish channel flow?  

Easy answer, it flows both directions.  Sooner or later, regulars to the San Juans learn to love or hate Swinomish Channel.

  Many skippers form an opinion on their very first transit through this popular eleven mile alternative to Deception Pass. Sailors and under powered puttsters fighting the current, hate it, but turn them around and  suddenly their tune changes as the current whisks them along at 

four miles per hour.

         One day we pulled in to the city float at La Conner and I grumbled to a local boater about how we had been battling the current for hours on our way from James Island.  I remember his comment, he said, "The current flows one way for twenty three hours and then reverses, and no one knows when."  We all laughed and I figured I should get over it.

         I came across this rule of thumb posted on the Port of Skagit County website for estimating the current direction.  

        The rule of thumb for estimating Swinomish Channel current 
direction at La Conner goes like this:

The current flows   north   from 2.5 - 4 hours before high tide to 2.5 - 4 hours after high tide
The current flows   south   from 2.5 - 4 hours before low tide to 2.5 - 4 hours after low tide
Slack water occurs 2.5 - 4 hours after high or low tide, not at the tide change like in some areas.

          You will still need to consult with high and low tide predictions for La Conner to put these rule of thumbs to use.  Be forewarned, many people consider La Conner tide predictions as hocus pocus because they are often wrong.

      I cannot remember this rule so I am going out on a limb here and offering my own memory trick as follows.   We already know that in the San Juans a rule of thumb is that the current flows north on an incoming tide (flood) and south on the ebb, and we know in the Puget Sound and southern area it is basically the opposite.  So my memory hack is to consider Swinomish Channel as part of and subject to the San Juan rules of thumb.  This means, Swinomish Channel flows NORTH on the flood just like the San Juans, but it is late due to distance.

FYI - did you know that all of Swinomish Channel (at least where land is) is a "No Wake - Slow Zone"

Click below for satellite view of Swinomish Channel North end and Cap Sante

Current Page Tables for use with the Canadian Current Atlas of the San Juans

     Are the old current charts still accurate?   

Yes, they will be good forever, it is the page number that you need to know because like the tides they repeat year after year but you need to know which pages have the correct charts for your cruise.  Just like tide forecasts need a date/time and location to be useful, so do the current charts.

Here is  a url to find date tables for use with the Canadian Current Atlas. There are others online, or you can do the mathematics outlined in the front of the Canadian Atlas.

http://code.borsboom.io/current-atlas-tables/

If you don't know what this is referring to, you need to go to the Current Atlas guide posting several years ago  >> go now by clicking this link 

Current atlas for San Juans and Gulf Islands


BTW if you find something you like, or helps you, you should say so.  Lots of people work for nothing, not even a thank you!

No No Not me, I work for nothing cause I'm bored
JR

Big arrows are faster currents. An hour later or earlier will be different. What you need is a date and time for this forecast. That's why you need a page table for the current atlas, just like you need the date and time when you look up tide forecasts.