Altitude has an effect on your boat's performance, with decreasing altitude boosting horsepower and increasing altitude causing a reduction. The culprit, if you will, is with atmospheric pressure.

You see, air becomes thinner as altitude increases. For people, this means breathing is a little more work when strolling a mountain-top town vice walking along the oceanfront. The same sort of thing happens with boat engines. As they become starved for oxygen, horsepower is diminished. For instance, an engine that has been set for sea-level cruising would lose around 10 percent of its horsepower if operated at 3,000 feet and 20 percent at 6,000 feet. If, on the other hand an engine was set for higher elevations, running it at sea level for a prolonged period could potentially lead to stuck or melted pistons.

If you are thinking of trailering your boat on a vacation of two or more weeks to a significantly different altitude, consult a qualified marine service technician about possible fixes. Among the things that might be suggested are changing the outdrive gear ratio, installing different size main jets or increasing or decreasing the pitch of the prop.

– Linda Hoff