Bainbridge Currents for Sept 12, 2015 [1 Attachment]

Jeff Knakal

What time does the race start? The website says 9:30 for the long course, but typically we start later.

On Tuesday, September 8, 2015 11:33 AM, "Steve Bennett bennett_seattle@... [SoundRowers]" wrote:

[Attachment(s) from Steve Bennett included below]
Thanks Tom, for a more thorough analysis than you would have gotten from me.   I totally concur with your call.  Here is my read:
If a 5 hour Marathoner took the counter-clockwise route, she would face almost no current at the Agate Pass Bridge with the Slack occurring at 10:47. At Point White, about half-way, she would have a supporting current of 1.5 kt, building through the pass.

If however, she opted for the clockwise route, she  would be fighting that same 1.5 kt current when she hit Point White, and facing an uphill 4 kt current at the Agate Pass Bridge.  Not a big choice this year.
Look forward to seeing you all on Saturday.  We'll have the usual soup and bread at the finish, also a nice selection of commemorative hats, thanks to Stoneway Concrete.

Tide charts attached, I think.


From: "tkreyche@... [SoundRowers]"
To: SoundRowers@...
Sent: Monday, September 7, 2015 6:10 PM
Subject: [SoundRowers] Bainbridge Currents for Sept 12, 2015

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

...Tom Kreyche


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.

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.

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.