Three Things The Supermoon Means For Boaters

Super Tides Accompany The Supermoon

The supermoon, or perigee full moon, on November 14, 2016, will bring the moon closer to Earth than it has been since January 26, 1948. If you haven’t heard, a supermoon is a full or new moon that occurs concurrent with the our moon’s closest approach to Earth. What’s more, the moon won’t come this close to Earth again until November 25, 2034. That makes the November 2016 full moon the closest and largest supermoon in a period of 86 years! Last month’s full moon, as well as the full moon in December, 2016, will also be supermoons. But tonight’s moon is the big one.

Supermoon NASA screen shot
A screen grab from a NASA ScienceCast video. ( ) NASA

How does a supermoon affect boaters? Here are three things boaters should be aware of during a supermoon

Slacken Dock Lines If you keep your boat at fixed dock, the dock-lines could get tight. A super-moon, means super tides,( properly called, perigean spring tides ) and that means extra-high, and extra-low water could result in your boat either hanging from its lines–or. getting pulled under by them. Make sure they are adjusted properly.

Perigean tides diagram

Perigean Tides Diagram

” Super tides” caused by the Supermoon, are actually called, perigean spring tides. Courtesy NOAA

Prepare for Strong Currents The extra tidal range will create stronger current. This will be especially apparent when transiting coastal inlets. The increased volume of water could make conditions more treacherous than they otherwise might be.

Rough Inlet
Coastal inlets can be especially rough during perigean spring tides, such as those that occur during a supermoon. Kevin Falvey

Beware of Flotsam Super-high tides reach higher and farther on to shore and can cause debris like logs, discarded appliances and other items to become flotsam ( Jetsam, by the way, is stuff thrown from a boat; flotsam is, “naturally occurring” floating debris). Keep an even sharper eye out in the days following the super-tides of a supermoon.

Super -high tides can reach far up the shore often causing debris, like this log, to become boat-holing flotsam. Fungus Guy


On the brighter side, a supermoon is 30-percent brighter than normal, so visibility for nighttime navigation should be even better than during a normal full moon.

NOAA photo of creepy sea creatures
This NOAA photo proves almost anything can happen during a perigeal full moon ( a.k.a. , “supermoon.”) Courtesy NOAA