I recently misread a tide chart and faced a tough challenge getting back to my start point. Are there any simple rules or articles that anyone can recommend to read for future planning?
What did you misread?
Would be helpful to describe exactly what you did vs. what you thought you did.
This might
help understand tides as well as the charts.
http://www.elcamino.edu/faculty/tnoyes/readings/07ar.pdf
I liked it because it explained how many factors influence the actual tide which can vary from what was forecast.
Besides all the discussion of
the science of tides in the linked article, which was excellent, most free printed tide tables are for a specific location.
Pay heed to the specific location for the tide prediction, because if you aren’t at that one then they will usually have a correction table somewhere in the thing to adjust for different nearby locations. Predicted tides don’t occur at the same time in all locations. Further up a river or a different area along the coastline, and the tide can be off by a good bit. I suspect that may have been your issue.
Nothing beats experience
Are you concerned about fighting a tide, and/ or having to drag your boat through hip deep mud back to the car?
NOAA charts give velocities at several positions at max ebb or flood. There are many sites on the net that give peak and minimum heights versus time, even way up tidal rivers.
Nothing beats actual experience in an area. The launch site facility on this web site often has good advice. There are plenty of people on here who can answer questions about specific areas. Kayak tour books are helpful too. A good GPS comes in very handy for making observations and avoiding a chain of bad decisions.
Tides and currents…
can doing two different things - it is not uncommon for them to be going in opposite directions. I paddled about 6 miles once on what the local tide chart listed as an outgoing tide and fought a stiff current most of the way. During that time the tide had dropped over two feet!
Yes, tides and currents are different,
while tides are responsible for currents they don’t always match. Just because high tide at the inlet is noon it does not mean the current will change at noon. NOAA has current predictions on there web site http://tidesandcurrents.noaa.gov/currents12/
Also weather can affect tides and currents.
currents
Assuming that there is about 3 hours between slack current and max ebb or flow:
1 hour after slack you will be at 50% max current
2 hours after slack 90% max
During planning, it helps to look at charts with bathymetry (bottom depth contours) to find shallow areas where the current will accelerate and form rips. Also if you HAVE to fight the current, look for more convoluted shoreline that will have back eddies. Straighter shoreline will have current all the way to shore. Sometimes back eddies only extend a paddle length from shore but it beats fighting the current. You can also link up rests in eddies with short sprints between and make it upstream in pretty strong current.
Not always
No disrespect Nick but that kind of generalization will get you in alot of trouble if you are not on a coastal beach.
For instance, tides in the east river of ny are hydraulic and the flow velocity coincides almost directly with height about mean sea level. So max flood occurs at high tide.
Current vs. Tide
Since Nick specified max flood or max ebb, and not high or low tide, his generalization is generally correct.
I’ve seen many people get bitten by wrongly assuming that max current coincides with high or low tide.
While this is true (or close enough) in many locations it is decidedly not correct in estuaries where gravity flow of one or more rivers opposes or strengthens that tidal ocean currents.
Sometimes, it’s not just a matter of
current or flow either w/r/t getting back.
Read a tide chart wrong for some areas, particularly southeastern coastal estuaries, and you may spend several hours in a mud flat where you are the only mosquito bait around.
If you can stomach it,
study David Burch’s book on kayak navigation “basics.” That’s what he calls it–I think his book goes beyond the basics. (Kamals, anyone?)
But if I remember correctly, he included some very good info on things that influence the predicted times and rates of tidal streams. Also, I have a tide and currents almanac with some locations’ flows described as being “erratic”. At least one location supposedly always flows in one direction. Interesting stuff.
Still, for a more basic intro to tides, start with Franco Ferrero’s and Ray Killen’s books on kayak navigation.
Since I too am still getting acquainted with understanding these things, I study the predictions, look at the charts to see if everything makes sense, and then I ask locals to comment on the predictions. There could be typos, you know–I caught one on a chart that showed something that was supposed to be an ebb noted as a flood (or vice versa). Another time, I was in one area where another kayaker familiar with it commented that NOAA needed to do a better job with their predictions, because he had found them to be WAY off, timewise.