Let’s suppose you are paddling amongst small estuaries and bays with small islands between you and the Gulf. You have a compass. You have high tide and low tide times at particular areas a few miles away. Without looking at the shoreline or noticing water covering or exposing oyster beds, is there a geografic current directional flow way or is it the easiest way to and from the sea? I suspect one may have to determine which high tide comes first at certain points and flow will be toward the second point for a high at a later time. Any tricks to learning about tides and current in skinny waters in SW Florida?
No trick, but it is next to impossible
unless you are a long time local, who knows the waters and the winds.
They never change the same twice.
If you look at the tide heights for various days, there are high highs and low lows and very seldom are they at the mean low.
There are times a low tide will be a foot above mean low, and all of this changes according to the wind direction and speed.
One day the tide might change equally behind a particular key or island, with it heading in opposite directions at exactly the half way point of the Island while the next day at the exact same time as high, it might only be running in one direction from a quarter of the way around the Island and the other direction for the other three quarters.
Yesterday we were slightly north of big Coppitt Key coming around the east side of O"hara Key, and the tide was supposed to be going out, but we were battling a very strong incoming tide.
Others may differ, but this is from a lot of experience.
A friend who has written a book on the hidden coast of the Gulf up near the big Bend area tried to research it, and couldn’t even get good data from the Coast Guard. - He was told to “ask the locals”
I have paddled northern tidal waters
for many years. They are predictable.
I dutifully get my tide tables out for Gulf paddling, and every year without fail by day three I throw them out…one days low is another’s high…highs and lows are not equally spaced.
Wind fouls up everything. The speed and the direction constantly change and affects the tide. Nothing like reserving a chickee and finding out that there is no water within half a mile!
Or having to make a two mile detour to avoid slogging through mud thats not normally there.
You just have to go with whatever nature throws at you that day. You can take your tide tables and try to figure out how the recent winds might have affected things.
Like Jack said, Currents are much more complicated than tides, especially in areas with multiple inlets/outlets between an inland waterway and the ocean. I don't know anything about the tides down there, but we have similarly interesting and confounding currents up here, largely as a result of the very high tidal range, causing water to move very quickly and swirl around in great eddies even out in open water where you wouldn't expect it.
The best you can hope for is to become reliable at predicting the areas you paddle frequently, and then use what you've learned to try to extrapolate that to new areas, so you can make some guesses and combine that with any available current tables and local resources.
Pay attention whenever you're out. Make observations about which way the water's going, and how fast. Write it down, and compare it to time before/after high or low tide at a given station near by, and note the tidal range on that day. After a while you'll start to see the patterns for that area, and be able to predict what you'll encounter the next time out, by looking at the tide tables.
Applying that knowledge to unfamiliar areas is tough, but you'll be more prepared to make a guess based on what you've learned about the oceanography in your home waters.
Depending on whether NOAA considers where you're paddling to be navigationally significant, these current tables can either be extremely helpful, or merely a tease.
Have a beer at a local marina
While you are there, ask about the tides. Unless there is a region-specific guide, on the order of Eldridge’s for the Cape Cod area, those kinds of areas are all local knowledge.
JACK & MEDIC HAVE IT RIGHT…
As does Celia as well.
Tides regularly rise & fall in many places -and they do down here, too. They rise and fall with exactitude, according to the dictates of Sir Isaac and Johannes, the "laws" of celestial motion, including the relative masses and distances of the earth and it's moon -just plain (well, sometimes not so plain to many) physics. They come and go, rise and fall -ebb & flow? -with precision!
But... There's always one of those hanging around, isn't there...
But down here along the Gulf, and particularly in Florida Bay, and specifically in the areas of the Keys, the precision gets perturbed and and sometimes rather rudely interrupted by winds and sometimes construction. Winds can build up a lot of water in the backcountry, and when the winds die, the water levels fall -sometimes in opposition to the currents which result from the flow of water caused by tides.
Compounding the problem is the vastness of shallows in Florida Bay, and the Keys backcountry. These areas are fantastic for paddlers because they're intrinsically beautiful and remote, and, in part because they're too shallow for perhaps 95% of power boats to navigate -so they're not there to disrupt life...
And that same otherwise wonderful backcountry is also where a change -a not only significant, but IMPORTANT! -change -from forecast tide levels can result in patches -sometimes acres and even square miles -of flats -sometimes sandy, more often not oozy marly knee-to-thigh-swallowing muck -that could have floated your boat in other circumstances, or contrarily, passageways where low water is noted on charts can be freely floated...
So it's a wise paddler who gets the day's weather info and not merely the day's tides -and talks to local fishermen & guides for a little invaluable local knowledge! -and (tries to) account for these variables as they
-Frank in Miami
Estuaries and large sheltered bays
generally lag the predicted high and low tide times, some very significantly.
As a local example, “The Race” at the western end of Fishers Island, NY lags the tide by an average of about 90 minutes because a good chunk of Long Island Sound drains and floods through this 2-3 mile wide gut, and it cannot equalize the height for an additional 90 minutes on each side of it.
And as Jack said, they are all different, and a little different every day. It adds to the fun of navigation.
the NOAA site is terrible
for the Gulf of Mexico coast down by the Everglades.
Try this one instead
No currents given. In my experience depending on the tidal change for that day the currents can be up to 3 mph. Mostly just a PITA not a paddle stopper.
(Last year on the Lopez was close though. I like to think I was just tired)
NOAA and predictions
NOAA’s predictions are based on decades of accumulated data, not on a mathematical model, but that’s the way of ALL tides and currents publications.
Keep in mind as you plan a trip that this information is a prediction based on yearly averages for many years and it does not take into account weather - such as wind and precipitation. Wind will cause the tides to rise much higher and faster than the predictions and currents can be greatly affected by precipitation levels.
As an example, here in Washington I play a lot in Deception Pass, with average currents of -5kn to 4.5kn, which is the primary drainage for Skagit bay. If you look at a chart of Google Earth you’d think Saratoga Passage is the drainage, but it isn’t. Skagit Bay is the drainage for the Skagit river, which is a rather large river with a significant outflow. When the weather has been rainy or the river is high due to melt off in the mountains it dramatically changes the times of minimum flow and the speeds of flood and ebb.
Having lived and worked in the Gulf I can tell you that the weather is only one piece of the puzzle, especially is you are near the drainage of any river. The flow rate of those rivers will change the character of the entire region if it is uncharacteristically high due to rain or flooding upstream.
For planning trips, I recommend the NOAA site and it’s tables of secondary corrections, in addition to local knowledge, but this is just a planning aid from which to create a baseline. The dynamic nature of the sea will always keep you guessing.
Local knowledge outside of the bars
If you don’t relish hanging out in bars, there are other good sources of local info on tides and currents.
When I was at Fort DeSoto County Park, I wanted to check on what I thought should be the flow’s direction in one of the passes. Asked someone who should have known and never got an answer. Asked a ranger at the county park next; he didn’t know, either, but he immediately introduced me to a fellow ranger who did. Not only did I get the answer to my question (my educated guess was correct), but I got an explanation on other tidal effects on the relevant area, complete with photo aerials.
Scratch around some, and you might find someone who’s eager to share his knowledge.
You can also patch together bits of info that aren’t exactly what you need but might form a decent mosaic to answer your questions, or at least give you a starting point that 's not total guesswork. For example, here at Tybee, NOAA provides tide level data for 3 nearby sites but current predictions for only 1 of those. So there is a pretty good picture of what happens at that 1 place but missing pieces for the others. Still, between study of those tables and the chart and applying common sense, I have a reasonable idea of what to expect when I paddle.
The question I’m struggling with is, in an area where the tidal streams might meet (flood from two directions) how do you figure your timing on that one?
tides coming from two directions
can make for confused seas or whirlpools. Kinda depends on the topography. I have seen both in Florida at the end of mangrove islands.
Its kind of like reading ever changing whitewater. At the end of the bay about three miles from Willy Willy is a tidal chute. The wind was coming from one way and the outgoing tide on another. It made for a surfing wave some two feet high…the only way to get across was to ferry into an eddy and power up.
Another place on the Lopez River mid tide with tides coming from two directions simply made for clapotis to power through…waves from two directions.
Depending on how much water moves through an area you might want to time your travels to go with the first two hours of the tide cycle and avoid the two hours of mid tide. It gets interesting with the Florida tides though as they arent six and a quarter hour intervals. And to complicate matters you have to figure in tidal delays inland.
The rule-of-thumb times
for slack, max ebb, and max flood don’t apply here, either. From what I’ve noticed, slack runs an hour or more after L or H. Max current speeds hit more like 2 to 2:30 before, not 3:15. Times for H hit only 1 minute apart at two spots, but those same spots have L that are 17 minutes apart. Makes things harder to figure out. And meanwhile, the sandbars keep moving around and lowering/rising.
There’s never a dull moment, though.
Thanks for the imput. I appreciate the time you all put forth expressing experience and knowledge on the matters as well as the suggestions. Merry Christmas and happy paddling.