So You Want a Saltwater Pontoon Boat?
- Captain Verde
- Jun 3
- 5 min read
Updated: 3 days ago
Operating a pontoon boat on saltwater is a whole other world apart from small lakes. Taking a boat out in heavy seas is the least of the factors. Saltwater is corrosive and harsh on boats, including motors. Many manufacturers offer “Saltwater editions” in their model lines. But from experience, we can tell you that some makers do a much better job than others in prepping their models for saltwater.
Construction – Tri-toons, tri-toons, tri-toons. There is not enough we can say about the stability and additional seaworthiness that the third pontoon adds to a pontoon boat. The additional buoyancy is “money” when you are in adverse sea conditions, and trying to get back to safe harbor. And always remember, in saltwater environments, the nice calm conditions as you leave your dock will likely deteriorate while you are out on the water. There’s nothing like the assurance of a tri-toon to get you home.
Ideally, makers will use heavier stringers over the pontoons to support the vessel as it deals with the additional flexing and stresses through choppy seas. It’s impossible to know if they have or haven’t. But something that you can check for on your own is the under deck shielding. By looking under the deck, you should see nothing but aluminum shielding underneath covering all of the decking members. If you see any of the stringers or marine plywood, this is not a saltwater boat. The shielding is not just for protecting the under deck, but rather is provides important rigidity and support to the stringers and decking. We have seen plenty of these boats that are marketed as saltwater capable but are not fully shielded. The construction of these boats are not up to dealing with 2 or 3 foot seas, and will see a very shortened life on saltwater.
Splash guards welded onto the front of the pontoons is a popular option and can reduce the spray getting into the boat. More and more makers are adding these fins to the front of their pontoons for comfort. But these can be problematic in choppy seas. These fins encounter profound levels of force from the choppy seas. Some manufacturers try to make these as rigid as possible to deal with those forces. But the reality is that when the fin is rigid enough, and refuses to give, that transmits the forces onto the pontoon themselves, right on the welding point. One of our boats actually suffered a breach right where the fin was welded onto the pontoon, and started taking on water. After patching the breach, we cut off all of the splash guards to prevent any further harm to the other pontoons. We also noticed something interesting on another one of our boats also fitted with splash guards. That maker of the boat installed fins that were far more flexible, and those splash guards actually “gave” with the force of the water, thereby putting much less stress on the pontoon welds.
Zinc anodes will be especially important in saltwater, as they fend off the corrosion of the aluminum. These must be replaced on a regular basis, and they should be spot checked regularly. We have had issues at times where a neighboring boat at our marina was leaking trace levels of electrical current into the water, and causing the zincs of nearby boats to get consumed prematurely. This happens far more often than you would think, and without anyone having a clue. If gone unchecked, significant harm can come to your aluminum pontoons. If you do not have a lift or a high and dry, and your boat sits in the saltwater for long periods of time, you must be extra vigilant in maintaining your pontoon boat's zincs.
Electrical, lighting, instruments – These are all a challenge on saltwater. Even if your pontoon boat is a “saltwater edition”, it might not mean the wiring and electronics can stand up to saltwater environments for great lengths of time. It’s a question you want to present to your dealer and manufacturer in a pointed way. And you want to make sure the vessel's warranty covers electronics and lighting. Ask if the vessel maker utilizes tin-plated copper throughout the hull. Over time, saltwater will actually corrode copper wiring even through the insulation. We’ve had engine cables fail, even though they were protected from moisture, where the strands of wire were no longer copper, but a dark gray brittle straw that easily crumbled when you handled it. Granted, these were heavy engine cables that were in daily use for 5 or 6 years. But standard electronics wiring might fail much quicker. If you are a night time boater, it’s imperative you keep a spare set of clamp-on battery operated nav lights. You will without a shadow of a doubt come to a time where you will need them.
Length Overall - Lastly, but most importantly, is the length of your boat. In order to safely navigate through choppy waters, a long water line is essential. A pontoon boat that’s less than 21 feet in overall length will struggle mightily through chop that is even just a 1 ft high. Your boat will just be too short to navigate across the wave troughs. Even on a large lake one will see active waters on a windy day if you are on the long end of the fetch (fetch is the distance over water the wind is able to blow and create waves). Vessels starting at 23 ft of length are dramatically more stable in choppy waters than boats that are 21 ft or less. And they will be better suited to getting you back to safe harbor when weather conditions unexpectedly fall apart. Consider the 23 ft as the "magic number" for pontoon boats.
Conditions at Sea - Speaking of unexpected conditions… a competent captain will always check on weather conditions before setting out into open waters. There are many weather apps available online that are extremely helpful in predicting conditions out on the water. Many of us sea captains check the winds before anything else, and there are many apps that are specific to wind conditions and forecasts. Many of these apps will give you a full winds map (sourced from NOAA, the national weather service
), and also include actual wind speed readings from nearby weather stations both on land and on the water. Winds are a great predictor of wave heights, and wind direction, and these apps will also tell you what kind of winds to expect later in the day when its time to get safely home.
As for actual wave heights, the national weather service has a network of buoys that measure and report sea conditions, and many of them send updates every 30 minutes. The data includes not just wave heights, but also wave direction, and wave period. The wave period is crucial, because 2 ft waves that are 4 seconds apart is vastly difference from 2ft waves that are 8 or 9 seconds apart. They are much much easier to navigate in your pontoon boat when waves are 8 and 10 seconds apart, when we start referring to them as “rollers”. There are many apps that report these buoy observations, but you can also access them via the web directly on NOAA's website. Just Google “NOAA national data buoy center” and find your local buoys. Also remember that seas are caused by winds.
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