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dive tides 101

Posted: Thu Sep 16, 2010 9:47 pm
by spudgunman
I remember a bit from the OW but it didnt go into detail much.. is there any Tides for Divers 101 on how to plan and best times to plan etc

Re: dive tides 101

Posted: Thu Sep 16, 2010 10:26 pm
by CaptnJack
Its site specific, do you have a particular place in mind?

Re: dive tides 101

Posted: Thu Sep 16, 2010 11:03 pm
by spudgunman
no I was just reading that other thread you gave advice on and was interested in more.. but didnt want to jack that thread. I was wondering how you came up with the time to get dives in before and be done by and how you calculated it

Re: dive tides 101

Posted: Thu Sep 16, 2010 11:54 pm
by LCF
The beginning of planning is getting a good set of tide tables, or a site to use, like THIS one. You have to inspect tides and currents, for the station that is closest to the place you want to dive (so you have to know the geography a bit). But some sites have individual quirks -- for example, Keystone, which is very current sensitive, is diveable on virtually any flood, but can get hairy on strong ebbs. Skyline, a current-sensitive site, is best dived on small but not minimal exchanges; on tiny exchanges, the current may never reverse.

The Fischnaller book (Seattle Shore Dives) has tide instructions and corrections for many of the popular local shore diving sites. I'm not aware of anything similar for boat diving locations, which is why I end up asking for advice.

Re: dive tides 101

Posted: Fri Sep 17, 2010 3:12 pm
by spudgunman
I see ...

thanks for the info makes sense I thought there was just something easy you can apply

Re: dive tides 101

Posted: Fri Sep 17, 2010 3:57 pm
by CaptnJack
spudgunman wrote:I see ...

thanks for the info makes sense I thought there was just something easy you can apply
generically...
neap tides are better for genuinely current sensitive sites. basically 1/2 moon.
"spring tides" (which happen all year round) occur on full and new moons and these are stronger.

The Fischnaller book is a good place to start for the most popular shore sites.

For boat sites there's a now out of print map of current substations which can help locate the closest or most relevant. Since that's not available, you'll end up using a compass, ruler and a chart to decide if "2 miles north of __________" is relevant or not. If you have something in mind we can try to help here or at least provide experience to cross-reference. Some boat sites are honestly too complex to predict, the dungeness crane and diamond knot are probably in this category. Since currents are slowed by the friction of shorelines, most shore sites can be guesstimated good enough.

Re: dive tides 101

Posted: Fri Sep 17, 2010 4:33 pm
by selkie
Just jump in and if you can't swim against it the current is too strong try again in an hour until you get it right. I am just kidding being aware that currents can be a factor and assembling information before a dive is a good start. However, you still need to arrive early and watch the conditions before diving. Going to a new to you sites with people that dive them frequently is a good way to learn but does not alleviate you of the responsibility of looking up the info and educating yourself. As you begin to learn how different sites work you will start to be able to have a better educated guess about other sites. Local knowledge is always good just don't take it whole cloth.

Re: dive tides 101

Posted: Tue Sep 21, 2010 9:13 pm
by Alexitt
www.planyourdive.com is a pretty good site for local diving. It will generate site specific tables and also projected flow charts. Just have to join and login... no fees

Re: dive tides 101

Posted: Tue Sep 21, 2010 10:19 pm
by spudgunman
ohh nice !