The Comer Channel and the Moon

White Pepper transited the Comer Channel today. The Comer Channel is the deep water passage from the Exumas (via Long Island) to the Ragged Island Chain. The Raggeds are also known as the Jumentoes. Shallow draft boats (read here small and medium sized catamarans) can take a short cut through the Hog Cay Cut. Hog Cay Cut has a controlling depth of 3 feet at low water. White Pepper with 5 feet, 4 inches of draft (maybe more) does not want the hassle; hence the Comer Channel.

We left Thompson's Bay/Salt Pond on Long Island at 8 am. We were are the eastern entrance to the Comer Channel at 10 am and had no difficulty in passing through. White Pepper was at the western entrance of the Comer Channel by noon never having seen a reading under 8.7 feet. We followed the Explorer Chart's way point explicitly and never even saw a coral head.

“But what about the Moon? You said you were going to write about the Moon!”

The reason White Pepper had such an easy passage was that it was timed to start when the tide was half way high and rising and finish near high tide. How do you do that and have the sun over your shoulder to give visual clues? One way is to time the trip to coincide with the new moon or full moon. Actually, two or three days after the new moon or full moon is probably better.

On the day of the full or new moon, the tide at Nassau is high at 8 am as it is in many open ocean locations. Two days later the tide is high around 10:30 am. The tide at the Comer Channel is about 2 hours after Nassau, and all of the bank sides of Great Exuma and Long Island are about 2 and ½ hours behind Nassau. Doing the math two days after the new or full moon the tide is half full and rising in the Comer Channel about 10 am and full about 1pm. It takes roughly an hour and half to two hours to get from Thompson's Bay to the Comer East way point. So a civilized departure time of 8 am is perfect. This event occurs 24 or 25 times a year. Water Cay, the first stop in the Jumentoes is easily reached by 3:30 or 4 pm.