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Navigating the Intracoastal Waterway (ICW)

By The Ahoy! Crew
Published November 3, 2022

There is something profound about traveling the river routes and coastal pathways of the Intracoastal Waterway (ICW). These local channels linked together provide a path for the seafarer to navigate their way through the country and perhaps even out to Mexico or the Caribbean. You can never plan too many days in advance because you need to constantly monitor the tides, currents, and weather while heeding Aids to Navigation (AToNs). Slowing down and enjoying the ride are key to thriving in this environment. You never know what the weather will bring, and marina amenities and re-provisioning can be more complicated than one may think. These tips will assist any vessel working its way through the ICW, from the Atlantic Intracoastal Waterway to the Gulf Coast, up the Mississippi River, and around the Great Lakes. Plan to budget at least a month to three months for your voyage, because slowing down is key to enriching your experience and ensuring your safety at all times. 

Tides and Currents

Respecting and understanding tides and currents will become a part of your daily life on the ICW. You may plan to enter a marina, but arrive and find the water so unpleasant that you need to divert and explore a few hours before attempting to dock. Or you may be hoping to cross a shallow shoal area, only to realize your draft requires you to wait for deeper water. Thus, monitoring tides and currents is an indispensable activity. The Ahoy! mobile app offers its users general forecasts as well as detailed map layers for wind, current, and waves.  Another resource used to monitor tides and currents is NOAA Weather & Tides app, which pinpoints radar, forecast, tide charts, and alerts from NOAA. 


You must think about your weather as being in transit, just like you. Watch the radar and work to understand where weather systems are headed and what to expect on your 50-80 mile voyage of the day. You need to review the weather at your destination as well to understand what the conditions of your arrival will be like. Fall into the habit of not just checking the weather first thing in the morning, but also going above deck and taking a moment to examine the water, sky, and any approaching clouds.

Identifying Aids to Navigation (AtoNs)

First-time navigators of this route must be aware that the ICW has no uniform system of buoys and markers to help an outside mariner travel through. Remember to keep the yellow square to your port side and the yellow triangle to starboard when traveling south, regardless of the color of the marker. 

Lateral markers are positioned to help you understand the boundaries of deep water, and they come in red or green. You must continue between the two lateral markers to stay in the channel. Multi-colored preferred-channel aids can feel overwhelming at first, but just remember: if the color on top is red, then keeping the aid to starboard will bring you to the preferred channel. Passing the aid on port brings you to the secondary channel. In order to get where you want to go, you must pay attention to the colors of markers and the yellow shapes that accompany them. 

These aids are also key to keeping your vessel in deep water. Keep binoculars handy to identify markers not just in low visibility, but also when the sun is close to the horizon. Keep an ear listening for approaching vessels at all times, especially at bends in a waterway. You want to make sure you navigate safely, and AtoNs will help you do just that if you know how to read them properly.  

Safety when encountering other vessels

Some channels of the ICW are narrow, and vessels must be alert to other vessels and avoid collision at all costs. The skipper must remember that the vessel going downstream has the right of way. Remember POP, or Pass on Port, to ensure you navigate your course starboard and always pass approaching vessels on port. In crossing situations, if the approaching boat is on your starboard side, then you are the give-way vessel. The stand-on vessel technically has the right of way, and, as the give-way vessel, it is your responsibility to maneuver so that the stand-on vessel can cross well ahead of you. Remember to pay attention to lights at night, with green on starboard and red on port. Navionics sonar charts will be a great friend in low visibility, but don’t forget to always keep a lookout and have a pair of binoculars on hand. 


Your relationship with bridges is about to change dramatically. Gone are the days when you used the bridge to cross over a local body of water. Now, you must fit under it. Bridge schedules will become a part of your morning preparation routine, and getting in touch with a bridge tender isn’t always as easy as it seems. Locate phone numbers and websites a day or two ahead of time. Don’t forget to utilize the Time to Waypoint (TTW) included in your electronic chartplotter, which will help you call ahead for bridge openings and minimize the time spent wandering in wait. 

Fixed bridges are another matter. This automobile infrastructure does not open, limiting the clearance height of the passing vessel. On paper, fixed bridges on the ICW have a vertical clearance of 65 feet--but in practice, you will find that is not always the case. One notable example is the Julia Tuttle Bridge in Miami at Statute Mile (STM) 1087.2, which has a vertical clearance of just 56 feet. Tidal movement also impacts bridge clearance, and mariners should be wary of crossing in high water. Always consult the ICW Cruisers Guide or other online or print resources when advancing toward a bridge. Review the location of fixed bridges by Statute Mile (STM) to understand where you may encounter these bridges on your journey. 

Protecting Yourself and Your Investment

Life on the water is unpredictable, which is why smart seamen know to protect themselves and their investment with boat insurance. Ahoy! has a variety of plans tailored to fit your needs and cover you while you cruise the ICW. We’ll have your back from when you need a tow to when you’re impacted by a storm. Get a quote today and get cruising with peace of mind as you make your way down the ICW.

Crossing to Mexico

The Intracoastal Waterway can take you all the way through Texas and to the Mexican coast if you choose. Coastal Mexico offers vibrant and lively expeditions for the skipper looking to explore internationally, but navigators must be safe and smart when traveling here. Don’t forget your passport and plan ahead when calling customs, re-provisioning, and finding places to moor. Boaters looking to skip the ICW and jump across the Gulf instead should be extra attentive to both the active and the abandoned oil platforms that pepper this body of water. Remember to read our resource “How to pick a weather window, prepare your boat, and plan a route for a long passage” if you’re looking to make a multi-day hop to the coasts of Mexico.  

The Journey

You won’t regret making the decision to navigate the Intracoastal Waterway of the United States. The curled locks of Spanish moss hanging from cypress and oak blocks the sun from blinding you in the morning as you work your way south. Maybe you see egrets glide and dive for breakfast, or see homes floating near the banks. Whatever your reason for choosing to navigate the ICW, it is an enriching adventure that will endeavor you to connect with your surroundings and self like never before, and it’s never been easier to prepare and stay safe on the water than today. 


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