Tide Management

6 Oct

October 6, 2018

Now that all the historically problematic NC inlet crossings have been surveyed by the USACE post Florence, the ICW run south is starting to look passable for most boats. (NOTE: the Socastee Swing Bridge will not be operable for a couple of weeks.)   Managing the tide will be important. In Lockwoods Folly, the surveys indicate that you might see as little as 4 feet of water at MLLW.  You want to be crossing Lockwoods on a rising tide due to the 4′ shoal between R46 and G47. At high tide you have an extra 4-5 feet of water.  About a mile east of Lockwoods Folly Inlet crossing near Stm. 320, there also is another 4′ shoal encroaching from the red side just past R36. Stay on center or to the green side as you pass this shoal.

Managing the Tide in Lockwoods Folly

Southport is a very popular stop with several fine marinas and a few anchorages, from which to stage for crossing Lockwoods and Shallotte. It is 37 statute miles to Myrtle Beach and 65 stm to Osprey Marina, with several other marinas in between. After leaving Southport, you will be in Lockwoods in just an hour or two.  Looking at the tides in a longer-term view will be helpful.  So when should you head for Lockwoods?

Below is the tide chart for October 20-25.  This would be a poor time to make the run.  The tide is low in the middle of the day. You might  leave early and  try to hit Lockwoods  on a falling tide when there is still  2 feet of help.  BUT, what if you run aground?  The water is falling rapidly; you might be stuck there for a while!   It is unwise to enter a known trouble spot like this more than an hour or so after high tide. You might leave Southport in the early afternoon, in time to catch the rising tide in Lockwoods.  That will leave you only another 3-4 hours of daylight to get to where  you are going.

A better scenario is to wait until October 28 to November 1.  Here you can enter Lockwoods in the morning with a rising tide, and have plenty of time to get to your destination.  These are planning decisions which you should be thinking about a week or more before you reach Southport.  It the timing is going to be off, you might want to  enjoy Wrightsville Beach or Carolina Beach for a few days.  Get rested, restocked, fueled and watered  during the time when the tide is not favorable.

There is one more factor to consider, too.  The tide does not always do as predicted.  The tide can run above normal or below normal.  If it is running below normal, it would be good to know that before you get to Lockwoods. There is a tide station at Lockwoods Folly inlet to give you the time and height for the predicted high and low water.  But what is really happening? At the NOAA-ODIN website(https://tidesandcurrents.noaa.gov/gmap3/)  there are a number of tide gauges which record in real time the actual tide height compared to the predicted water level. The graph below shows the actual tide height in Annapolis during the flooding tides we had in September.

NOAA has two tide gauges  in the NC coastal area near Lockwoods Folly. One is at Wrightsville Beach pier 30 miles to the east of Lockwoods.  The other tidal gauge is at Spring Maid Pier near Myrtle Beach 35 miles to the west of Lockwoods Folly.  All three locations have high and low tide within minutes of each other.  So why are these other two stations important?  They have tide gauges which display in real time the tide height, and from this you can tell if the tide is running above or below normal.

As you can see in the picture above, the tide has general been a few inches above the predicted height for the past couple of days.  At the time  this graph was captured, the tide was running 4 inches above normal.  Now 4 inches is not a lot, but consider if you knew it was running 4 inches below normal as you approached the inlet crossing.  You might decide to hold up and wait for a bit more tide before committing to the crossing.

Using the tide charts you can pick a tide window for crossing the inlet a week or more ahead of time.  And then the evening before you go, check the  NOAA ODIN website.

Passing though Lockwoods this year is going to be a game of inches.  If the tide is running  higher than normal, a few extra inches gets you through earlier, and if it is running below normal you know to wait before you get into the inlet crossing

Comments

  1. SAIL the ICW

    Thank you for your comments. I agree with you, that the chance of being caught in a hurricane diminishes if you leave the Chesapeake in November. There are many factors which may influence cruisers’ decisions. The departure date is always a point of debate. Leaving early gives you longer days and milder weather. For many cruisers this is important. Leaving late MAY push you past the hurricane season, unless there is a late season storm, but the days are short and the air is cool/cold.
    Cruising in the ICW can be fun and rewarding. There is a lot to see and do. As full time cruisers with no car, the ICW trip involves a lot of stops where we visit friends whom we’d not see otherwise. Personally, there are several places we would like to hop outside, however it is hard for us to maintain a web blog on cruising the ICW from 8 miles off the cost.
    Thank you for your thoughts on this. Have a safe voyage south.

  2. Smurph ( S/V Philyria )

    With another hurricane predicted to cross the panhandle and run up the coast, it seems to be a bit early to be going south. The early end to hurricane season in recent years may tempt folks to set out sooner than they should. I always need to keep it in mind that hurricane season ends in November.
    Taking advantage of the tail end of passing northern fronts, with NW winds blowing offshore (actually sailing:-), may make offshore passages a lot more sensible than trying to slog down the ICW with shoals and ancient broken bridges.

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