Slack Water at Hell Gate

There are (2) quick and simple methods for determining slack water. The best way is through use of Current Tables and the second way is through the use of the Tide Tables and a simple "Rule-of-Thumb."

The Current Tables

The simplest and most accurate way to determine the time of slack water at Hell Gate, is to simply check the NOAA Current Tables (or the tables of your choice) for the date in question and extract the information.


An excerpt from the NOAA Tidal Current Tables for "Hell Gate" for the dates from April 1st thru April 4th is provided below.

From looking at this table, you can see that slack water at Hell Gate on the 1st of April occurs at 0330, 0934, 1549, and 2148.

Hell Gate (off Mill Rock) Tidal Current Tables

Predicted Tidal Current April, 2011
Flood Direction, 050 True. Ebb (-)Direction, 230 True.
NOAA, National Ocean Service
  Maximum
Current
Slack
Water
Maximum
Current
Slack
Water
Maximum
Current
Slack
Water
Maximum
Current
Slack
Water
Day Time
h.m.
Veloc
knots
Time
h.m.
Time
h.m.
Veloc
knots
Time
h.m.
Time
h.m.
Veloc
knots
Time
h.m.
Time
h.m.
Veloc
knots
Veloc
knots
1 0017 -4.4 0330 0638 +3.5 0934 1235 -4.4 1549 1853 +3.4 2148
2 0048 -4.6 0408 0712 +3.6 1012 1305 -4.5 1625 1926 +3.5 2226
3 0119 -4.7 0444 0745 +3.6 1050 1336 -4.6 1700 1959 +3.6 2302
4 0152 -4.8 0520 0819 +3.6 1127 1410 -4.7 1735 2032 +3.6 2339

Hell Gate Rule-of-Thumb

In the event that you do not have access to Current Tables, you can use the following time offsets. On average, slack water at Hell Gate occurs 01:46 after high water and 01:43 after low water at "The Battery." Adding these corrections to the times of high or low water will give you a close approximation of the times of slack water at Hell Gate.

As a practical matter I use this system, but to avoid having to remember 2 different time corrections, I simply use 01:45 for both high and low water.

April - The Battery @ New York City (Tide Tables)

Date Day Time Height Time Height Time Height
04/01/2011 Friday 0142 Local 0.3 L 0749 Local 4.7 H 1357 Local 0.1 L
04/02/2011 Saturday 0225 Local 0.1 L 0828 Local 4.7 H 1436 Local 0.1 L
04/03/2011 Sunday 0306 Local 0.1 L 0904 Local 4.7 H 1512 Local 0.1 L

As can be seen in the Tide Table excerpt above, the first low water of the day for April 1st is 0142. Adding the low water time correction of 01:43 to that, you get a time of slack water of 0325 which is within 5 minutes of the 0330 predicted time in the current tables above.

The same thing can be done with high water. The first high water occurs at 0749. Adding the high water time correction of 01:46 to that, you get a time of slack water of 0935 which is within 1 minute of the predicted time in the current tables.

As you can see this is not as accurate as using the published Current Tables and differences of as much as 15 minutes have been noted, but it does provide you with sufficient enough accuracy to plan your passage in the event you do not have access to the published tidal current data.

       


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