how to read a tide chart

[Gabriel90512]

IM looking at a tide chart and i want to go diving on the 14th or 15th .. I want to hit the beach so i can dive the high tide

can some one teach me how to read this
tide chart. http://www.maineharbors.com/ma/augroc04.htm



Thanks

Gabe

 

[hurleyskis]

August 14th you've got high tide at 11:13AM and approx. 12 hours later at 11:14PM.
" " " " low " " 5:00AM " " " " " " 4:58PM

August 15th you've got high tide at 11:50AM and " " " " " 11:52PM.
" " " " low " " 5:38AM " " " " " " 5:37PM

Now that tells you when 'dead' high tide is. That said you should probably know about the "rule of twelths"....let's see if i can explain that and make some sense.

The rule of twelths say the water flows out/in at the following rate(s):
-during the first hour after the tide 1/12th of the total change in tide height will flow

(for August 14th 11:13AM high tide is a height of 7.7, at 4:58PM the low tide is at a height of 1.4. This is a difference of 7.7-1.4 = 6.3. So during the first hour after the high tide at 11:13AM the height will decrease by 1/12th of 6.3 = 0.525)

-during the second hour the change is 2/12th
-during the 3rd 3/12th
-during the 4th 3/12th
-during the 5th 2/12th
-during the 6th 1/12th
-6 hours later the tide has changed and the cycle repeats.

So why do you care about this????

This tells you that you'll experience the most tidal current 3-4 hours before or after a tide as indicated in the charts.


So if i were you i'd try to be at folly about 1 1/2 before the tide and that way you can get a couple of dives in before the tide really starts changing again. And i just might be there with you.

Hope that helps and wasn't too long! : )

 

[The Kraken]

Hurleyskis,
Thanx from a lot of us who didn't ask the question but wanted to know the same thing.

 

[Gabriel90512]

August 14th you've got high tide at 11:13AM and approx. 12 hours later at 11:14PM.
" " " " low " " 5:00AM " " " " " " 4:58PM

August 15th you've got high tide at 11:50AM and " " " " " 11:52PM.
" " " " low " " 5:38AM " " " " " " 5:37PM

Now that tells you when 'dead' high tide is. That said you should probably know about the "rule of twelths"....let's see if i can explain that and make some sense.

The rule of twelths say the water flows out/in at the following rate(s):
-during the first hour after the tide 1/12th of the total change in tide height will flow

(for August 14th 11:13AM high tide is a height of 7.7, at 4:58PM the low tide is at a height of 1.4. This is a difference of 7.7-1.4 = 6.3. So during the first hour after the high tide at 11:13AM the height will decrease by 1/12th of 6.3 = 0.525)

-during the second hour the change is 2/12th
-during the 3rd 3/12th
-during the 4th 3/12th
-during the 5th 2/12th
-during the 6th 1/12th
-6 hours later the tide has changed and the cycle repeats.

So why do you care about this????

This tells you that you'll experience the most tidal current 3-4 hours before or after a tide as indicated in the charts.


So if i were you i'd try to be at folly about 1 1/2 before the tide and that way you can get a couple of dives in before the tide really starts changing again. And i just might be there with you.

Hope that helps and wasn't too long! : )

so we sould hit Folly cover at about 2/2:30 pm for the best dive ?

thanks for the help ... i was having a hard time

gabe

 

[hurleyskis]

No, you want to dive it at/near high tide (or at least that's what i've been told) so since high tide is at 11:13AM on the 14th and 11:50AM on the 15th, i would try to be there at 9:30-10:00 (1-1/12 hours before high tide).

Diving at this time will assure you have plenty of water, minimal current, and enough time to get two dives in before the current starts ripping out too fast.

If you got there at 2/2:30 that would be roughly three hours after high tide and based on the rule of 12ths the tide would be flowing out the fastest at this time (3-4 hours after = 3/12th of total tide change).

That all goes out the window if your plan is to dive in a strong outgoing current in which your original estimate would be dead on!!

I may be heading up there this weekend. I haven't dove that site yet and wanted to give it a try. I hear parking isn't the best over there.

 

[Gabriel90512]

No, you want to dive it at/near high tide (or at least that's what i've been told) so since high tide is at 11:13AM on the 14th and 11:50AM on the 15th, i would try to be there at 9:30-10:00 (1-1/12 hours before high tide).

Diving at this time will assure you have plenty of water, minimal current, and enough time to get two dives in before the current starts ripping out too fast.

If you got there at 2/2:30 that would be roughly three hours after high tide and based on the rule of 12ths the tide would be flowing out the fastest at this time (3-4 hours after = 3/12th of total tide change).

That all goes out the window if your plan is to dive in a strong outgoing current in which your original estimate would be dead on!!

I may be heading up there this weekend. I haven't dove that site yet and wanted to give it a try. I hear parking isn't the best over there.

ok i got it now .. i was looking at it the other way around.
duh

 

[ScubaNorth]

Great Lesson.