The Sea Trial: What to Test Before You Buy a Boat

A boat at the dock can hide almost anything. A boat under way cannot. That is the whole point of a sea trial, and it is why no serious buyer skips one. Done right, a sea trial is a structured test, not a joyride, and the structure is what catches the problems.

Start cold, on purpose

Insist that the engine has not been warmed up before you arrive. A cold start is one of the most honest tests in boating: hard starting, excessive smoke, or an alarm on startup all point to issues a pre-warmed engine conveniently hides. Watch the gauges from the first second. Oil pressure should come up immediately, and the engine should settle into a smooth idle without coaxing.

The underway checklist

Once you are clear of the no-wake zone, work through the list deliberately.

• Time to plane. Note how long the boat takes to climb onto plane at normal trim with a normal load. Sluggish planing can mean a tired engine, a wrong prop, or a hull holding water.
• Full throttle. Run the engine up to its rated wide-open RPM range and hold it briefly. An engine that cannot reach rated RPM is telling you something.
• Hard turns, both directions. Listen for prop ventilation, cavitation, or anything that changes the engine note. Feel for play or stiffness in the steering.
• Trim and tabs. Run the trim through its full range under way, and the tabs if fitted. Watch that the boat responds predictably.
• Every system, not just the engine. Electronics, livewells, bilge pumps, lights, windlass, A/C if equipped. Turn it all on. Broken accessories are negotiating points; dead electronics are real money.

Then shut it all down, let it sit a few minutes, and do a hot restart. Hot-start problems are common and easy to miss.

Who should be aboard

You, the seller or broker, and ideally your surveyor, because many surveyors fold the sea trial into the survey and want to see the boat run. We cover how that fits together in the survey guide. Keep the guest list short. A sea trial with six friends aboard becomes a boat ride, and boat rides do not catch problems.

Red flags that should end the deal

Some findings are negotiation items. Others are exits. Walk away from unexplained overheating, visible water in the oil, an engine that will not reach rated RPM after the seller's explanation fails, or a seller who refuses a cold start or limits the trial to a quick idle around the basin. A seller who will not let the boat be tested is answering your question for you.

After the trial

If the boat passes, you will know, because the trial will have been boring, and boring is exactly what you want. Any issues the trial did surface go straight to a mechanic for a repair estimate before you finalize price. Waypoint lists verified mobile and shop mechanics across Florida at Waypoint's mechanical directory, and a pre-offer estimate is cheap insurance on a big decision.