Boat lifts sized to the boat, the tide and the pierhead

Why owners fit them

A boat kept in a salt creek is being worked on continuously by the water it sits in. Growth on the hull, corrosion on running gear, and the slow attrition that comes from permanent immersion all proceed whether the boat is used or not.

Lifting the hull clear between uses stops most of that. It also removes the daily anxiety about wind, wake and tide moving a boat against a structure, and it makes the boat easier to keep clean.

The counterweight is that a lift is a piece of machinery in a corrosive environment carrying a heavy load over water, mounted on a structure that has to be built to take it.

Capacity is not the boat weight

The most common specification error is sizing to the manufacturer dry weight on the brochure.

The load that matters is the boat as it actually sits: fuel and water aboard, batteries, engine or engines, hardware, gear, and whatever has accumulated in the lockers over a few seasons. That number can be meaningfully higher than the dry figure, and a lift sized to the optimistic version is one being run at the edge of its rating every time it is used.

Beam and hull form matter too, because the bunks or slings have to support the hull where the hull wants to be supported. A lift that carries the weight but cradles the boat badly is still the wrong lift.

The tide range sets the lift type

This is where a Charleston creek differs from a lake or a low-range coast.

A lift has to lift from where the water actually is, and here that position moves substantially twice a day. Travel has to cover the working range, which pushes toward configurations with enough vertical reach and rules out some designs that are perfectly reasonable elsewhere.

On a creek that drains at low water, the low end of the cycle is a further constraint: the boat has to be retrievable and launchable within a usable window, and the lift has to tolerate the conditions at the bottom of the tide.

Common configurations

• Four-pile cradle lifts, the conventional arrangement where the pierhead and pile layout allow it, with the boat carried on bunks between beams.
• Elevator or vertical platform styles, which suit some sites and some hulls better and interact differently with the structure.
• Davit arrangements for small craft, tenders and personal watercraft, which are a much lighter structural proposition.
• Floating lift systems that sit in the water rather than hanging from the structure, which change the structural question but bring their own maintenance picture.

The structure has to be designed for it

This is the point most worth making. A lift concentrates a large load, applied and removed repeatedly, at specific points on the dock. That is a structural design input, not an accessory fitted later.

Where a lift is intended, the pile layout, pile depth and framing around the pierhead should account for it from the start. Retrofitting a lift onto a dock that was not designed to carry one sometimes works and sometimes means adding piles and reframing, which is a larger job on an existing structure than it would have been on a new one.

Where a lift is intended, it also belongs in the permitted design rather than appearing afterwards.

Corrosion and maintenance

Everything on a lift that moves is in salt air, and much of it is over salt water.

Cables are consumables. They are inspected rather than trusted, and they are replaced on condition. Failure of a lifting cable under load is the failure mode with real consequences, and it is also the one most reliably caught by looking.

Motors, gearboxes and switchgear want their enclosures intact and their connections dry. Sacrificial anodes, where fitted, are doing their job by being consumed and want checking.

Bunks and carpet degrade and can quietly start marking a hull. Guides and bumpers take repeated impact.

None of this is onerous, but it is not a fit-and-forget installation either.

Operating one without shortening its life

Most lift damage is not dramatic. It accumulates.

Level the boat before lifting rather than after. A hull hoisted crooked loads one side of the cradle and one set of cables disproportionately, and doing that habitually is how a lift ages unevenly.

Do not leave the boat hanging at full travel when it does not need to be there. Do not run the lift with a fouled or obstructed cable path. Rinse the machinery when you rinse the boat, because the salt that lands on the hull lands on the lift too.

And stay with it while it moves. A lift is the one piece of equipment on a dock that can do real damage while unattended, and the failures that matter tend to announce themselves with a noise before they announce themselves with a consequence.

Storm season

Decide in advance what happens to the boat when weather is coming, because the decision is worse made in a hurry.

A lift is not a storm mooring. Boats left on lifts in serious weather are exposed to wind loading at height and to surge that can lift a hull off its bunks entirely, and the structure carrying them was designed for a static load in ordinary conditions.

For most owners the plan is to remove the boat well ahead of a storm rather than to trust the lift, and the useful version of that plan includes where the boat goes and how much notice the move needs.

Boat lifts sized to the boat, the tide and the pierhead — common questions

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