The Sea Trial – What is a sea trial? Do I need one?

Taking a boat for a sea trial—or basically a “test run”— I feel should be an essential part of the boat-buying process for higher value vessels. What to look for during this test, however, isn’t always clear to new owners even if they are experienced boaters due to the new boats complexity and new systems. This said there are several areas worthy of your attention during a sea trial, but the final decision to do one is up to the buyer.

Here is Ontario sea trials do not seem to be as popular as I have seen in the Caribbean or the United States boat markets. I am not exactly sure why this is but I suspect it has to do with the fact the boating season is so short and many buy & sell transactions happen during the off season when the boat is out of the water, or the weather is not suited for a sea trial. Weather and boating season aside I still stand by the recommendation for a sea trial on more expensive vessels. Does it make sense to sea trial an 18k boat with minimal systems and a single engine, maybe, maybe not, does it make sense to sea trial a 150k boat with twin engines, two generators, water maker, inverter charger, integrated control system, and a whole pile of other components, yes 100%

Basics of a Recreational Boat Sea Trial

Whenever possible, we believe in testing a boat like you plan to use the vessel. We see too many sea trials that are done on a boat loaded with low fuel, no passengers, no passenger belongings, empty holding tanks and an absence of gear. This just does not paint a true picture of the vessel being tested and should not be considered a valid trial. As well consider the weather including heat and sun, do you plan to operate in the summer heat? Find out if your air conditioning can keep up. Do you plan to operate late into the fall? Sort out if the heat works. Basic number one – setup a realistic situation.

Second Skiing and wakeboarding? Think back to the basics and put the heaviest person you intend behind the boat and see how the performance is. If you dealer or seller will not let you do it… move on.

In actual use, odds are the boat will be loaded with all of the above items and probably a few things I forgot, thus adding hundreds or even 1,000s pounds or more to your boat’s load. Keep in mind that the performance you feel during a lightly loaded test ride will never equal the real world performance at a much heavier operational displacement.

what are sea trials

The next basic we like to focus upon is the operational parameters of engines, gensets, and other equipment. In the cases of engines and gensets a real world test should be accomplished per the manufactures ratings. The ratings are easy to find for nearly every engine and generator on the market today. Simply hit the manufactures site, search the model, and download the PDF. Within the PDF you will find the operating parameters for the equipment.

Engines and drivetrains can potentially be some of the most expensive equipment to repair on the vessel. To check the engine health the engine should be operated in a method to see if it will deliver the rated RPM without overheating or having other abnormalities for the specified time within the manual. Many manuals will specify a temporary power rating, and a continuous power rating. The engine and transmissions should be able to run without issue at the continuous power rating, this will not damage or harm the engine if it is in good health. Does the engine overheat? Transmission temperature and pressure ok? Will the engine not make RPM? Excessive smoke or steam? Any yes answers and it is time to start diving deeper into the engine and drive system and head back to the docks.

Generators should be tested in much the same way, gensets have specifications for power out put and RPM. During the sea trial load up the generator and observe how it behaves. Again the generator should be able to run continuously at the rated power without any issue, RPM should not flux or cycle, voltage output should be steady, it should not overheat, when loads or added or removed the genset should quickly fix any variations in RPM or voltage. Personally I find that using the vessels air conditioners, water maker, and refrigeration components provide a great opportunity to load the generator on a sea trial. Second, while testing the long term loading on the generator it give you a chance to review the performance of the items you have the generator loaded with.

After a check of the other operational equipment not used to load the genset this should conclude the basics of sea trialing the engine room. Next lets talk about boat performance and ground tackle performance.

Next up for the basics of the sea trail are focusing on actual boat performance, because at this point we have decided that the engines are in good health and we are ready to move on to some more complex maneuvers and tests. At a minimum we would be seeing if the boat will make the advertised performance speeds from the manufacture, does the boat track in a straight line at idle?, at power?, are there abnormal noises shifting from forward to reverse, what do the engine mounts do shifting from forward to reverse, what do the mounts do at higher speeds shifting from forward to reverse (with time for the transmission to spin down)? Any findings here should be documented and or recorded with video for a qualified mechanic to review.

At this point of the sea trail we like to start getting into the actual boat performance, checking steering, ground tackle, and deck equipment. We will save these items for a future post.


Based in the GTA, Toronto Marine Surveyors serves central Ontario as far north as the Muskoka’s, East to Ottawa, and West to Sarnia.  We will travel to the USA as required.

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