Tide Graphs

[Beboandles]

we usually dive on charters and have started diving jetties. i am confused by different people showing me different ways of looking at the tide graphs.we usually dive an hour before high tide and havent had any problems but i am interested the other times.what are the indictactors you use to determine if the diving will be favorable during the day.
thanks for your knowledge.

 

[Diver0001]

It really depends a lot on local conditions. In addition to the astronomical tide there is something called "age" of the tide, which more or less means "how much delay" between the changing of the tide and the effect it has on conditions in a particular place. The most reliable way I know of getting familiar with what that means in a particular location is to consult experienced local divers and/or to dive it. Another tide related factor is the phase of the moon and "spring" and "neap" tides, meaning the highest and lowest tides of the month. When this happens is also related to the age of the tide. Around where I live it's generally two days after a full or a new moon. It's good to keep that in mind, especially when diving sites that are subject to strong tidal currents.

In addition to the tide, wind and rain are significant factors. Wind and rain both affect the viz and wind can affect surface conditions to the point of making entering and exiting the water very risky/difficult. Again, local knowledge is important but as a general rule I would cancel most dives if the wind is harder than force 5.

R..

 

[spectrum]

Tide charts, marine forecast, general weather forecasts, buoy conditions and the exposure of the site to wind. If you are up in a deep bay or estuary then you need to get the offset for that location since slack tide will lag. There is a site that predicts this but I don't have that link with me right now.

Over time you come to know what a site is apt to be like under given conditions. Watching recent seas and weather can be a rough predictor of visibility.

Pete

 

[bmcsteve]

This is the one that I use:

Tide Predictions

 

[Beboandles]

thanks for the responses.i will start trying to track the locations in the fl panhandle that i am interested in.being its only a 3 1/2 hr drive i would like to be able to choose days i can get the most dives in and would like to learn the correct way to read the graphs.
thanks again

 

[Doc Intrepid]

This is the one I use:

Tide Tool for the PalmPilot

Its pretty simple. The curve illustrates the ebb and flow of the tide over each 24 hour period, the apogee of the curve is slack tide (e.g. tide is not moving in or out). You want to dive the slack.

One trick is to note the total rise/fall - it varies based on the phases of the moon.

Point is that some parts of the world experience drops of 11'-13' or greater during certain times of the month.

What does this have to do with you?

Visibility.

Look at any month of a charter boat schedule. Then look at your tide tables.

Some weekends the tide variance will be something like 2'-3'. Other weekends its 12'-13'.

(These numbers are examples, they will be different for you in Florida.)

The point is that you may experience much better visibility if you plan your diving during periods of relatively small tidal changes, rather than during weekends involving major tidal changes. This is because the higher amounts of moving water stir up sediment and particulate in the water.

You may be safer, also, because major tidal changes can involve a great deal of water moving over short periods of time, and (at least in the PNW) divers have been swept away by swift moving tidal currents that they misjudged.

FWIW.

YMMV.

 

[Beboandles]

thanks doc!!! for the helpful info especially about the visibility.