A question about tides.

[emcbride81]

As far as shore diving, how do you gauge tides and currents? I know that tide charts tell you when tides will change, but is there a way to determine current strength. I have a severe lack of knowledge on this subject!
My concern is obviously being pulled out to sea. As far as shore diving is concerned, what is the real threat of that happening (outside of a rip current)? Any other old salt knowledge on tidal/current flow would be appreciated. I am mainly concerned with East coast (especially New England).

 

[rawls]

I would simply get a local area orientation for the specific dive site. The dive shops around this area can tell you what you will need to know about the currents at the site. It is definitely a good idea not to dive a site that has potentially strong tidal currents until you do get an area orientation from those who dive the site. Even then I would suggest diving the site with someone familiar with it. Attempting to gauge currents by yourself could be disasterous.

 

[sambolino44]

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[Melicertes]

As far as shore diving, how do you gauge tides and currents? I know that tide charts tell you when tides will change, but is there a way to determine current strength. I have a severe lack of knowledge on this subject!
My concern is obviously being pulled out to sea. As far as shore diving is concerned, what is the real threat of that happening (outside of a rip current)? Any other old salt knowledge on tidal/current flow would be appreciated. I am mainly concerned with East coast (especially New England).

You might find the following links useful for shore diving:
http://www.wetsand.com/swellwatch/swellwatch.asp?CatId=296

http://magicseaweed.com/New-England-Surf-Forecast/21/

Just note that the information above, and any other information from the Internet for that matter, is only a place to start. Don't rely on this stuff alone/at all; at best they are pretty pictures with a hope of a glimpse of what conditions might potentialy look like. The best way is to find someone that knows the ocean where you're at and spend some time with him/her and ask them to explain to you how to read the local waters. Get to know the tell tale signs. Salted divers, fishermen, skippers etc.

Just my 2 bubbles.

 

[Melicertes]

Check out [post=2961466]this[/post] post.

Hmmm, I like that.
Thanx

 

[Charlie99]

As far as shore diving, how do you gauge tides and currents? I know that tide charts tell you when tides will change, but is there a way to determine current strength. I have a severe lack of knowledge on this subject!
My concern is obviously being pulled out to sea. As far as shore diving is concerned, what is the real threat of that happening (outside of a rip current)? Any other old salt knowledge on tidal/current flow would be appreciated. I am mainly concerned with East coast (especially New England).

Local knowledge is a big help as far as dangers of dive sites, and particularly currents.

Some general comments -----

tidal currents are usually proportional to the difference in the high and low tides. This difference, aka tidal range, is greatest around new moon and full moon, and is smallest around 1st and 3rd quarter moons.

In addition to tidal currents, you can also encounter rip currents and longshore currents.

Rip currents are usually strong outbound currents that are only a couple 10's of yards wide. Water washes up onto a beach or lagoon over a wide area, but then goes back out to open sea via a narrow channel through a barrier reef or sandbar that parallels the shore.

Longshore currents can be from tides, but are often also created by the action of waves hitting the beach at a diagonal angle, and can also be caused by wind. As the name suggests, they run more or less parallel to the shore. These sorts of currents can be dangerous around the mouths of bays --- inside the bay you don't have a current, but if you go out too far the current pushes you sideways and perhaps away from an exit point. Similarly, longshore currents can be a problem around points since they can move you away from the intended exit spot on the point. Another thing that happens with longshore currents is that they intensify as the come down a coast and then get concentrated as the water piles up on a point that juts out into the ocean current. The upcurrent side of the point can have quite a strong outbound current.

Sometimes you can detect currents, and particularly discontinuities in currents by telltales such as a line of weeds on the surface, or a change in color. You can also sometimes guess at currents by the behavior of buoys and moored boats, but it is often difficult to figure out what is going on since they are affect by waves and wind as well as currents.

There isn't any magic secret. It's a combination of a lot of different little clues.

 

[Cacia]

When shore diving I find knowing the time it will switch is useful.

If you get in during slack, it can catch you with your pants down, so to speak.

If you get in once it has begun to run, you can at least plan going against the tide and drifting back.

I don't solo shore for these reasons, just too unpredictable here, unless very close to shore and someone is watching from shore....

 

[User0559]

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Now that is one slick site.

 

[Melicertes]

Local knowledge is a big help as far as dangers of dive sites, and particularly currents.

Some general comments -----

Very nice post Charlie

 

[ItsBruce]

Keep in mind that the effect of tides is least either at high or low tide. An hour before high tide is good. The effect is quite low and it is not sucking a lot of sand to destroy the visibility.