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 March 1st thru March 4th is provided below.

From looking at this table, you can see that on the 1st of March there are (4) slack waters at Hell Gate; occuring at 0318, 0924, 1548, and 2148.

Hell Gate (off Mill Rock) Tidal Current Tables

Predicted Tidal Current March 2018
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.
Vel.
knots
Time
h.m.
Time
h.m.
Vel.
knots
Time
h.m.
Time
h.m.
Vel.
knots
Time
h.m.
Time
h.m.
Vel.
knots
Time
h.m.
1     0318 0624 +4.00 0924 1224 -5.10 1548 1848 +3.90 2148
2 0048 -5.10 0412 0712 +4.10 1018 1312 -5.1 1636 1936 +4.00 2236
3 0136 -5.10 0500 0800 +4.00 1106 1400 -5.10 1724 2024 +3.90 2324
4 0218 -5.10 0548 0848 +3.90 1154 1442 -5.00 1812 2106 +3.80  

Hell Gate Rule-of-Thumb

In the event that you do not have access to Current Tables, you can use the times of high and low water at "The Battery" in New York City with the following time offsets.

On average, slack water at Hell Gate occurs:

  1. 1 hour and 46 minutes (01:46) after high water
  2. and
  3. 1 hour and 43 minutes (01:43) after low water.

Adding these corrections to the times of high or low water will give you a close approximation of the times of next slack water at Hell Gate.

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

The Battery @ New York City (Tide Tables)

Predicted Tides March 2018
NOAA, National Ocean Service
Date Day Time Height Time Height Time Height Time Height
03/01/18 Thursday 0124 Local -0.8 L 0731 Local 5.6 H 1402 Local -1.0 L 2000 Local 5.33 H
03/02/18 Friday 0215 Local -0.90 L 0819 Local 5.60 H 1449 Local -1.10 L 2049 Local 5.30 H
03/03/18 Saturday 0304 Local -0.90 L 0907 Local 5.40 H 1534 Local -0.90 L 2137 Local 5.30 H
03/04/18 Sunday 0352 Local -0.70 L 0955 Local 5.20 H 1617 Local -0.70 L 2226 Local 5.20 H

As can be seen in the Tide Table excerpt above, the first high water of the day for March 1st is 0731. Adding the high water time correction of 01:46 to that, you get a time of slack water of 0917 which is within 7 minutes of the 0924 predicted time in the NOAA Current Tables above.

The same thing can be done with low water. The next low water occurs at 1402. Adding the low water time correction of 01:43 to that, you get a slack water time of 1545 which is within 3 minutes of the 1548 predicted time in the NOAA Current Tables.

As you can see this is not as accurate as the prefered method - "using the NOAA Tidal Current Tables." While accuracies of within 1 to 8 minutes of the published times might be considered the rule, differences of 20+ minutes have been noted. The bottom line is this method can provide you with sufficient enough accuracy to plan your passage in the event you do not have access to the published tidal current data.

NEXT - East River - Timing Your Transit

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