What to Look for on a Sea Trial

If you can’t afford or don’t have access to a marine surveyor, you will need to rely on yourself to perform the sea trial. By the time you get to this stage of the buying process, you should have a pretty good idea what kind of boat it is you’re considering. You just need to confirm your choice or decide not to buy.

But what does a marine surveyor look for? It starts long before the boat goes in the water.

On your sea-trial, take the boat through a series of left and right turns, checking for play or friction in the steering, prop cavitation, and any unusual sounds. Doug Logan photo.
On your sea-trial, take the boat through a series of left and right turns, checking for play or friction in the steering, prop cavitation, and any unusual sounds. Doug Logan photo.

When the boat is on the trailer, walk around it thumping the sides of the boat with the bottom of your fist. The hull should ring with a solid whump and it should feel firm under your fist. This is particularly important in the transom area, where water intrusion typically appears first.

Look at the condition of the underwater gear. Is the skeg still nicely painted? Is the leading edge still straight and true or is it pocked and jagged from hitting rocks or sandbars? If it is damaged, keep its condition in mind when you shift the boat in and out of gear during the sea trial.

While you’re still on dry land, get on board and see and touch everything. Wiggle the grab rails to see if they’re loose. Sit in the pedestal seats to see if they’re still mounted firmly to the cockpit sole. Open up all the stowage compartments to be sure all the hinges are still solid. Also, use all your senses.

For example, give those stowage compartments a sniff to check for mold or mildew. Also smell under the engine hatch. You likely will smell gasoline to a certain degree, but anything overpowering indicates a fuel leak. Get down on your hands and knees and look in places where you wouldn’t normally look. You may discover missing hardware or frayed carpeting or upholstery.

Now for the sea trial, the most important part. I like the boat to be stone cold when I fire it up for the first time. If the engine’s rotating assembly is going to make any funny noises, it will be when it’s cold. Open the hatch so you can hear everything better. Does the starter engage smoothly and quietly? Does the engine rattle or knock when you start it? It should run with little more than a thrum of vibration and the hiss from the flame arrestor atop the engine.

As you back out, notice how the shifter works. Does it engage forward and reverse when the shifter is moved to the detents? Is there any binding or sticking in the shift cables? Not all signs of trouble will be deal-breakers, but it can help you develop your punch list if you decide to buy it.

When you advance the throttle, notice how difficult or easy it is for the boat to get on plane and see if it’s something you can live with every boating day. Once you’re up and cruising, take it to top speed. The boat should reach and hold that speed with no trouble. If you’re satisfied with the result, bring it back down to cruising speed;  3,500 rpm is a good rule of thumb.

At that speed — in an area where it’s safe to do so — take the boat into right and left turns. Do slalom maneuvers then full-circle turns. The boat should hold its line without hooking, washing out, or blowing out the prop. If the boat has a stepped bottom, don’t trim it down to do these tests. While you’re doing all this, listen for cautionary squeaks and rattles.

If you’re satisfied, cruise it back to the dock the way you normally would. Once you get back to an idle zone, open the engine hatch and do another full sensory check. Many times an engine that has been warmed to operating temperature will act different from one that is still cold.

Will this procedure keep you from buying a lemon? There’s a good chance that any used boat you buy will need some work not long after you buy it. However, I can tell you after years of testing boats using the techniques listed above, you learn a lot about any boat this way. The method will uncover mechanical foibles and idiosyncrasies, yes, but it also will highlight — perhaps most importantly — whether you like it enough to buy it.

A previous version of this article originally appeared on Boat Trader in April 2015.


Written by: Brett Becker

Brett Becker is a freelance writer and photographer who has covered
the marine industry for 15 years. In addition to covering the ski boat
and runabout markets for Boats.com, he regularly writes and shoots for
BoatTrader.com. Based in Ventura, Calif., Becker holds a bachelor’s
degree in journalism and a master’s in mass communication from the
University of Central Florida in Orlando.


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