How do I measure my boat for a lift?

The four numbers to write down

These are the dimensions a lift is actually built around, and all four can be taken in an afternoon with a tape, a plumb bob and a pencil.

• Maximum beam. Across the widest station of the hull, rub rail included, because that is the width that has to pass between the guide posts.
• True overall length. From the furthest point forward, pulpit or anchor roller included, back to the furthest point aft. On an outboard boat that is the tips of the engines, not the transom.
• Running gear depth. How far the lower units, a shaft and rudder, trim tabs or a transducer hang below the lowest point of the hull. That number sets how deep the cradle has to travel, which is the whole conversation on a shallow slip: see boat lifts in shallow water at low tide.
• Fully loaded weight. Hull, engines, full fuel at roughly 6 pounds per gallon for gasoline, water, batteries and gear. Building that figure properly is a job of its own, and it is the one that decides capacity, so we hand it to what size boat lift do I need.

How to take them so the numbers are honest

The measuring itself is where accuracy is won or lost:

• Level the boat first, on the trailer or floating on a calm morning. A boat sitting bow-high gives you a length that does not exist.
• Measure straight lines, not the hull. Drop a plumb line from each extreme point to the ground, mark both spots, and run the tape between the marks. Following the curve of a hull with a tape always reads long.
• Take beam square across the boat, not diagonally, and at the widest station rather than wherever you happen to be standing.
• Write down what the tape says. Rounding to the nearest foot is how an inch of interference gets discovered on install day.
• Take every number twice, on different days if you can.

The ones people get wrong

• The model number. It is a name, not a measurement.
• Spec-sheet beam. Published beam sometimes excludes the rub rail, and the rub rail is real hardware that occupies real space.
• Deck width on a pontoon. A pontoon or tritoon is measured outside to outside across the outer tubes, never across the deck, and the pontoon and tritoon lift guide explains what bunks spaced to a deck width end up resting against.
• Dry weight. The brochure number rarely includes engines, fuel or anything you keep aboard.
• Measuring the boat and stopping there. The lift also has to fit your slip and your piling spread, and that half we measure ourselves.

Bring us your four numbers and we will check them against your water. Estimates are free and on site. See boat lifts or call (239) 397-3400.