Slack tide

[adm3745]

The only reference I have is down in West Palm beach, FL, there is a site called blue heron bridge. It is located on an intra coastal waterway only a mile or so from an inlet to the ocean.You must dive Slack tide (1 hour before HT to 1 hr after) because both current and visibility are severely effected outside of slack tide. The currents get strong. Because it is intra coastal, the period from high tide to low pulls alot of water from inland out of the inlet so the water gets brown. By diving on an incoming high tide all the fresh ocean water has moved into the site so viz is better.

 

[iztok]

That is a UK site and I am not completely sure what he is referring to.
Tidal predictions are generally made for specific tide datum stations along the coast. Other locations have to be determined by adding or subtracting the number of hours or minutes from the nearest tide datum station as found in the tide and current tables published by NOAA here in the states.

Example San Francisco Bay Tide and Current Tables

NOAA site NOAA Tides and Currents - Home

Slack water - Wikipedia, the free encyclopedia

It says I need:

"Slack water usually happens near high tide and low tide, and occurs when the direction of the tidal current reverses. Tide tables indicate the time of high and low water at ports and other locations. Slack water can be accurately calculated in most regions using a tide table or current table combined with either a tidal atlas or the tidal diamond information on a nautical chart."

So I need to find "tidal atlas" or "tidal diamond" for that particular area. I have no idea where to get that or how to use it once I get it.

 

[captain]

NOAA is the source for all such information.

 

[captain]

The only reference I have is down in West Palm beach, FL, there is a site called blue heron bridge. It is located on an intra coastal waterway only a mile or so from an inlet to the ocean.You must dive Slack tide (1 hour before HT to 1 hr after) because both current and visibility are severely effected outside of slack tide. The currents get strong. Because it is intra coastal, the period from high tide to low pulls alot of water from inland out of the inlet so the water gets brown. By diving on an incoming high tide all the fresh ocean water has moved into the site so viz is better.

I dove there last week. Slack water occured a few minutes after high tide.

 

[gcbryan]

I need bit of help understanding this in terms of when is the slack tide.

you can go to any number of online tools that would allow you to get times of high and low tides. How does one go from there to figure out period of slack tide?

I need to figure out when high slack tide period is on Cooper River in South Carolina. More specifically Old Rice Mill location.

So I picked up the days in question and used the following link:

http://www.mobilegeographics.com:81/locations/4408.html?y=2010&m=6&d=26

What data do I use to calculate slack tide? (Being new to the nautical terms etc. I am assuming that high slack tide is different than just high tide.)

Thanks!

You have to have a little local knowledge. You can go to a site like : http://tbone.biol.sc.edu/tide/sites_useastlower.html and find Old Rice Mill, West Branch, Cooper River. This will give you tide info. For current info you need to find the nearest current reporting station. This is where the local info come in. If you go to that site and locate Old Rice Mill you will also see several listings for current on the Cooper River. Pick one but you need local knowledge.

Tide info is the up and down (vertical) movement of water. Slack refers to a lack of current which is a horizontal movement of water. In the absence of restrictions slack is usually close to high or low tide but when inland and around other restrictions it can vary greatly.

The terminology for slack current is "slack before ebb" and "slack before flood". SBE would be close to high tide and SBF would be close to low tide. Again SBE means that waters are high and soon will start to lower or ebb. A graphical respresentation helps to understand all this.

 

[UCFKnightDiver]

Thanks!

So given the info from above link:

Old Rice Mill, West Branch, Cooper River, South Carolina
33.0783° N, 79.9250° W

2010-06-26 5:26 AM EDT 0.33 feet Low Tide
2010-06-26 6:12 AM EDT Sunrise
2010-06-26 7:31 AM EDT Full Moon
2010-06-26 11:30 AM EDT 2.50 feet High Tide
2010-06-26 5:24 PM EDT -0.10 feet Low Tide
2010-06-26 8:32 PM EDT Sunset
2010-06-27 12:05 AM EDT 3.22 feet High Tide
2010-06-27 6:09 AM EDT 0.34 feet Low Tide
2010-06-27 6:12 AM EDT Sunrise
2010-06-27 12:14 PM EDT 2.50 feet High Tide
2010-06-27 6:06 PM EDT 0.09 feet Low Tide
2010-06-27 8:32 PM EDT Sunset


You would say high slack tide is between:

2010-06-26 11:30 AM EDT 2.50 feet High Tide
2010-06-26 5:24 PM EDT -0.10 feet Low Tide

But that is weird as it is quite a lot of time between 11:30a and 5:24p.

No, it's 10:30am-12:30 pm for the high tides, and 4:30pm-6:30pm for the low tide. 1 hr before and 1 hr after, so a 2hr slack tide period, I would recommend diving at high slack tide usually.

 

[terrydive1]

I need bit of help understanding this in terms of when is the slack tide.

you can go to any number of online tools that would allow you to get times of high and low tides. How does one go from there to figure out period of slack tide?

I need to figure out when high slack tide period is on Cooper River in South Carolina. More specifically Old Rice Mill location.

So I picked up the days in question and used the following link:

http://www.mobilegeographics.com:81/locations/4408.html?y=2010&m=6&d=26

What data do I use to calculate slack tide? (Being new to the nautical terms etc. I am assuming that high slack tide is different than just high tide.)

Thanks!

I use the tidal predictions from Captain Johnny's site Cooper River Dive Charters - CooperRiverDiving.Com when I'm diving the river. Usually you can figure on it slowing down right around those times. As everyone else has pointed out though, they are only predictions. I advise you to keep someone on the boat during the dive in case they have to pick you up. Also, if your looking for artifacts/fossils, make sure you have a South Carolina hobby license. DNR has been checking charter operations to make sure the divers are licensed.