Rod,
The tides in SF Bay are very complex. I use the SF Bay version of the TideLog. I didnt find a website showing the back of the book that contains the current flow diagrams but thats where you find the real information on current. Its very detailed supplying not just the predicted current through a passage hour by hour but using labeled flow arrows icluding where its concentrated around obstructions etc. Heres one look at it. http://www.bask.org/articles/tech4_tides.html Besides a TideLog book on SF Bay you are going to want charts. Not everything that is a big expanse of water on SF Bay is passable. There is a restricted deep water shipping channel where sailboats lose their right of way to shipping. In addition, when its really blowing on SF the big boys (container ships & tankers mostly) enter the bay flying to maintain steerage in what will become a 30-40 knot cross wind as they turn approaching Treasure Island. All they can worry about is running a precise course and speed. Its very common for casual sailors to misjudge the intended course of big ships and its quite common to hear ships issue a 5 blast collision warning as they prepare to pass under the GGB inbound. You can see the casual sailors trying to clear directly out of the way directly in front of the vessel however thats not the issue. A few that didnt read the chart will head south to clear the path. Unfortunately the ship is about the veer 15-20° south to follow in the inbound channel that turns under the bridge and all of a sudden a new group realizes the 5 blast were for them. Id also like to recommend you read up on and practice dead reckoning while sailing on SF Bay using your GPS only as the answer book. Dead reckoning will teach you to plan the drift caused by currents and in the end youll be better at complex solutions than your GPS. Phil Agur <http://www.catalina27.org/public_pages/profile270.htm> s/v Wing Tip C270 LE #184 MMSI 366901790 From: [email protected] [mailto:[email protected]] On Behalf Of RobAdkins Sent: Sunday, July 25, 2010 9:59 AM To: [email protected] Subject: [IC27A] Re: And now....Current Events thanks everyone, i figured that was the case and i wanted corroboration. it just makes sense. here in sf bay the currents can be very strong, as much as 7-8 knots or more. --- In [email protected] <mailto:IC27A%40yahoogroups.com> , "RobAdkins" <robadk...@...> wrote: > > hi all, > > i have a question regarding tides and curent speeds. after searching the web and finding way too much info on the subject I decided i'd just ask someone in this here group. here goes. if a high tide and a low tide have a difference of 6 feet will the current speed be greater than if they had a difference of 2 feet? i know there's more factors involved here but i just need the dirty basics. thanks! -rob >
