Navigating Inlets

Chris Riley by Chris Riley Updated on July 30, 2019. In nauticalknowhow

Arguably, one of the most dangerous locations that a small boat can be located is in the jaws of an ocean inlet with a strong onshore wind and a maximum ebb tidal current. The waves become greater in height and shorter in period.

These conditions are very dangerous for all vessels, especially the smaller ones. Today, while training with one of my boat crews, we exited the Fort Pierce Inlet on a strong 4 knot ebb tidal current and nearly 20 knots of easterly wind. Due to the opposing forces of wind and current, the waves in the inlet were four to six feet in height. Although we took green water over the bow, our 41 foot Coast Guard vessel easily handled the conditions. After about an hour of offshore training we began our transit back into the inlet.

As we approached the mouth of the inlet we were surprised to observe a small 16 foot open boat, powered by an outboard engine, approaching the mouth of the inlet from inshore. It they had entered the larger waves just offshore from their position they would have been in jeopardy of being flooded by the six foot breaking waves. Wisely, the boat full of young teenagers turned around and headed inshore. Yes, they were wise to turn around, but were they wise to approach so close to the dangerous location? Would they have taken their boat so close to the edge of Niagara Falls and turned around at the last minute?

Many a mariner has underestimated the dangers associated with ocean inlets. If the boat’s propeller was suddenly fouled by debris or the engine had mechanical problems, the strong ebb tidal current would have quickly carried them into the larger seas and threatened them with capsizing. Shortly after we moored up from our training mission, this boat full of teenagers ironically ran out of gas not far from the station and called us for help. Needless to say they were very lucky that they did not run out of gas during their close approach to the inlet.

All mariners should be extra careful when transiting North America’s inlets during the winter months. The ocean tends to get rougher during the winter due to the much stronger winds associated with this season. Our inlets become much more dangerous places for small vessels. Not only is it rougher, but the waters are colder, increasing the threat of hypothermia in the event that a boater is thrown into the water as a result of capsizing.

Before determining whether to transit an inlet and head offshore, mariners should obtain a marine weather forecast and know the state of the tidal current. The mariner should also know the limitations of their vessel. Some vessels are more suitably designed to handle the rougher conditions. The mariner must also be careful not to over-estimate their personal abilities to safely handle their vessel during the heavy weather conditions.

If you were already offshore when the weather deteriorated, causing the inlet to become too dangerous to transit, it is often best to wait offshore for the tidal current to begin flooding. The flooding tidal current will significantly improve the conditions, usually reducing the wave height and increasing the wave period. An attempt to transit during the worst conditions can result in broaching, capsizing or even worse; pitchpoling. Pitchpoling occurs when a following sea lifts the stern of your vessel up so high that the vessel tumbles end over end.

It is very difficult to determine the inlet conditions from seaward. While offshore your vision is limited to seeing the smooth backs of the waves as they roll towards the inlet or shore. Whereas from shore or inside the inlet, you can clearly see how bad the conditions actually are as you observe the whitewater spilling off the tops of the waves. The nighttime conditions of darkness worsen the situation 1000-fold. If you are concerned for your safety, by all means call the nearest Coast Guard Station and describe your situation.

Strong offshore ocean currents can also cause dangerous conditions similar to those found in inlets. The Gulf Stream running north at 4 knots and an opposing wind of 20 knots will result in the wave height being considerably increased and the wave period being decreased. The Gulf Stream can also cause very dangerous conditions for small boats. Transits across the “Stream” should be carefully planned with a close eye kept on the weather.

To learn more about this topic I encourage you to complete a U.S. Coast Guard Auxiliary Boating Skills and Seamanship Course. To find out the location of the course being offered near you call 1-(800) 368-5647. If you are interested in helping others while helping yourself please consider joining the U.S. Coast Guard. Call 1-(800) GET-USCG




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