Re: Bainbridge Currents for Sept 12, 2015


Debbie Natelson
 

Thanks Tom!  Great analysis.  So nice of you to share.  I have a sched conflict and may not be able to make this years Bainbridge race :( -- but have a great one all who do get to do one of my favorite races.  Always a challenge, no matter which way you go. 

Debbie

On Mon, Sep 7, 2015 at 6:10 PM, tkreyche@... [SoundRowers] <SoundRowers-noreply@...> wrote:
 

Here's my take on the tidal currents for next Saturday's race. I'm interested to hear other opinions.


...Tom Kreyche


Sources
http://www.deepzoom.com/index.html
https://tidesandcurrents.noaa.gov/currents15/tab2pc2.html#17


Overview

Without taking wind into consideration, a CCW direction will almost certainly be more favorable. If there is a South wind, CCW will certainly be preferred since the East side of the island is more exposed to the wind and it will be a downwind leg. Racers may wish to consider a CW direction if there is a strong North wind. This would take advantage of a downwind leg on the East side of the island, but racers would face opposing the tidal currents.


Counter-Clockwise

With a 9:30 a.m. start time, racers will enter the Passage at around 9:50 a.m. They will face a 1 kt ebb tide at the North end, at the same time there is 2 kt ebb at the South end. The current will be decreasing rapidly so the trip through the Passage should get easier rather than more difficult. During the leg along the West side of the Island, there will be a transition from a weak ebb at the N end to a weak flood towards the S end. Earlier arrivals at Rich Passage will take better advantage of the weak .5 to 1 kt ebb, since it weakens fairly rapidly and goes slack at 11:29 a.m. to noon.


Clockwise

This is less favorable than counter-clockwise. Racers headed South on the East side of Bainbridge will be facing a weak ebb tide. Rich Passage goes slack at 11:29 a.m. to noon – earlier arrivals will also face a weak ebb through the Passage. A greater problem occurs approaching Agate Passage, where the flood will be increasing rapidly and peaking at 4.2 kt at 2:10 p.m. Racers will typically be facing a 3 kt or greater flood. The earlier arrival the better.


Tidal Currents
Agate Passage N End - Flood Direction, 230 True, Ebb (-) Direction, 032 True

Max Current -2 kt (ebb) at 7:44 a.m.

Slack Water 10:45 a.m.

Max Current +1.7 kt 2:03 p.m.


Agate Passage S End - Flood Direction, 216 True, Ebb (-) Direction, 037 True

Max Current -3.9 kt (ebb) at 7:56 a.m.

Slack Water 10:48 p.m.

Max Current 4.2 kt (flood) 2:10 p.m.


Rich Passage W End - Flood Direction, 238 True. Ebb (-) Direction, 055 True

Max Current -3.4 kt (ebb) at 9:05 a.m.

Slack Water 11:29 a.m.

Max Current +3.2 kt (flood) at 2:55 p.m.


Rich Passage Off Pleasant Beach

Max Current  -3.1 kt (ebb) at 9:26 a.m.

Slack Water 11:59 a.m.

Max Current 1.7 kt (flood) at 2:48 p.m.




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