Key Features of a Boat Lift
If you're looking to install a boat lift, you should know what you're getting into. Boat lifts are installed on docks, pilings out on the water or next to docks, seawalls, inside boathouses and on shorelines. There are also floating boat lifts installed on the water and moored to a dock. Features of boat lifts to consider are:
- Lift capacity – how much boat weight can the lift handle
- Number of motors – the number of motors on the lift
- Gear system – type and structure (fully enclosed or open)
- Amps – 110 volts, 220 volts and 240 volts
- Material – marine grade aluminum, stainless steel, galvanized steel or a combination
- Warranty – inclusions, exclusions and term
- Control – radio control, smartphone control, manually operated switches or wheel
- Assembly – bolted or welded together
Common Boat Lift Materials
The type of metal used in the boat lift frame and cables determine the required maintenance the structure will require over time.
Aluminum is the most common material found in boat lifts. It is lightweight and durable material. It will not rust, so it works well in saltwater as well as freshwater. Aluminum lifts usually have stainless steel hardware. The aluminum lift works well in shallower water areas and in fluctuating waters requiring frequent lift adjustments. Aluminum boat lifts are easy to work with. One of its drawbacks is that it is more expensive than galvanized steel.
Galvanized steel makes a sturdy boat lift, but the finish will corrode. Corrosion development is slowed by hosing the lift down after each use. Galvanized steel boat lifts use galvanized steel hardware, so corrosion in crevices is certain to eventually occur despite the special paint used to cover welded areas. Steel is heavier than aluminum so works well in deep water installs and where the lift does not have to be removed for winter. If galvanized steel is the material choice, consider buying a welded black steel boat lift that is “hot-dip” galvanized. The entire frame is given a zinc coating.
Lift frames that are bolted together require more maintenance because bolts always come loose eventually, resulting in corrosion and loss of frame alignment. It also causes faster wear-and-tear on the other components, like cables and pulleys. Remember the boat lift is subjected to weather, waves and usage. A welded boat lift stays aligned because there are no bolts holding it together.
One more boat lift feature to consider is the material used for the cables. The cables are the workhorses of the boat lift, ensuring your vessel is lifted and lowered safely. Most cables are made from stainless steel or galvanized steel.
Stainless steel resists oxidation (corrosion) because it is made with carbon steel which has 10-percent chromium. When chromium is exposed to air, it develops a thin layer of chromium oxide. This makes stainless steel regenerative. The layer of chromium oxide protects everything underneath. One drawback to stainless steel is that prolonged exposure to salt water will inevitably lead to corrosion. The only way to prevent the corrosion is by washing down the cables with fresh water.
Galvanized steel cables have a thin layer of zinc oxide through processing which increases resistance to corrosion. However, the zinc coating is not regenerative, so eventually the cables will rust when the coating wears off. Galvanized steel cables are is usually less expensive than stainless steel cables.
Types of Boat Lifts
There are different ways to describe the types of boat lifts, like cantilevered versus vertical or elevator versus cradle. This section tries to give an overview of most of them so you know what is available.
Elevator style lifts – These lifts are frequently installed when the boat is kept in a narrow canal or other restricted space or there are two pilings on or close to the dock, rather than four. The elevator style lift has a configuration that looks like two or more forklift-like arms extending out. The arms are attached to the mechanical system installed on the pilings or dock. This type of lift is easy to use, but part of the aluminum frame is always under water. This makes it more susceptible to corrosion. The lift rests on the bottom on a near-vertical or vertical beam. Routine maintenance includes inspecting and changing anodes installed to prevent corrosion.
Cradle boat lifts (Four or eight pile beamed cradle boat lift) – This is a cable-drawn lift. Using the four post motorized lift as an example, it has four posts and two parallel beams at the top of the posts. Each beam contains a motor driven shaft that runs all the way through the beam. Cables are connected at each corner of the beams at the top and to a boat cradle. The four cables wind around the two shafts on each side of the boat either clockwise or counter clockwise to raise or lift the boat. Boat lift maintenance for this type is minimal because it is completely out of the water. There are also beamless cradle lifts with winders on each of the pilings. Cradle boat lifts are considered one of the most secure structures.
There are two kinds of systems – cantilever boat lift and vertical boat lift.
The cantilever system has minimal moving parts and travels at an angle. It has a fixed base frame, a swing carriage that moves the boat forward and back for boat loading or release, and hydraulics or motorized cable network that lifts and lowers the boat. When the boat is fully raised, the cables carry no weight. Lift equipment does not reside below the waterline. The cantilever lift is commonly used for smaller boats.
The vertical boat lift lifts the boat straight up. The boat is placed on the cradle structure and the boat is pulled straight up and out of the water.
Floating boat lift – The free-floating boat lift is used when you are not allowed to permanently attach the lift to a fixed structure or there is no fixed structure to attach to. However, it is also used by people who want to minimize the risk of damage to the boat from wakes and storms that cause the boat to rub or bounce up and down against the dock.
The lift uses hydrodynamics. The lift floats in the water and is moored to a piling or dock. A gangway makes the lift accessible. Since it floats, it can be used in most water depths with the appropriate anchors. The lift frame is attached to flotation tanks that are filled with water to sink the drydock and emptied of water via a pump to raise the boat out of the water. Since it free floats, it does not stress the dock, pilings or seawall and does not use cables.
The floating boat lift is ideal for situations where the water rises and falls. There are floating boat lifts available for small to very large boats (think: 45 feet long). Also, this type of boat lift is easily moved if necessary, and some models can be expanded to fit bigger boats by adding modules. They are very easy to maintain because they do not have electricity or cable gears and they adapt to any water level change.
Freestanding boat lift (Bottom standing lift) – The vertical or cantilevered freestanding boat lift has its own base that is mounted in water or on land. Mounting in water, like at the bottom of the harbor or lake, requires adequate water depth and an even, firm bottom type that can support the structure. Water depth requirements are usually no more than 3-10 feet. Mounting on land makes it useful for boat storage during non-boating season. Add some wheels, and the lift can be moved around with ease.
It comes with a hydraulic, crank or electrical system that lifts the cradle and boat up or down. The main drawback to a land-based lift is that someone must lift the boat out of the water and onto the freestanding boat lift.
Davits – Davits are like cranes. Though frequently used for smaller boats, they are also used for larger boats when no pilings are available or allowed, there is only a seawall or there is very shallow water. The davit has cables that attach to hooks on the boat’s bow and stern to lift and suspend the boat. Having said that, there are pile mount boat davits installed by wrapping the lift around the pilings. The caution is that it is important to make sure the piling is not damaged or eroded below the water. So davits are available in seawall mount, pile mount and dock mount styles. The davit always needs secure footing which is often a concrete footing.
Overhead boat lift – This type of boat lift hoists the boat with cabling attached to joists or overhead beams. It is a cost-effective lift option but limited as to where it can be installed. The boat sits on a cradle or slings (sling lift) and is hoisted up by cables on a winder that is attached overhead. It is a great setup for a boat house or covered dock. It is one of the least expensive options and has no lift equipment underneath the waterline. Maintenance is minimal. However, slings can also cause rubbing on the boat’s hull.
Shore mounted lift – This lift style involves installing a ramp on shore that extends into the water. The boat is driven onto the ramp. A winch and cable pulls the boat along the ramp to the shore where it is out of the water.
Hydraulic Boat Lift -This type of lift has hydraulics and fluid lines under the water. The hydraulic system uses an electric motor and hydraulic pump to raise and lower the boat. The cantilever boat lift with hydraulics works best in water that does not fluctuate much and on a firm lake bottom. This type of lift has hydraulics and fluid lines under the water. The cantilever hydraulic boat lift has a maximum lifting capacity (in most cases) of 4,000 pounds.
The vertical hydraulic boat lift works good in deeper water that has some fluctuation It can be installed in firm, semi-firm and soft water bottom conditions. The vertical boat lift can also handle more than 4,000 pounds of boat weight.
Note that there are also high lift vertical boat lifts that can handle deeper water or greater water fluctuations than hydraulic driven systems.
Boat Lift Motors
Most boat lifts are powered with motorized hydraulics or a motorized or manual crank cable and pully system, except for the floating lift which uses hydrodynamics. Be aware there are variations by boat lift brand.
Motors and Gears
Boat lifts are operated manually or by a motorized drive system. The manual boat lift operates with a spinner wheel which the boat owner turns to run the hoist. It is obviously best used for smaller boats with less weight. This type of boat lift power system is likely to be found on inland lakes, i.e. people with a cabin on the lake who want their fishing boat stored above the water.
The motorized boat lift with the electric winch is a heck of a lot easier to operate, but does require a power source. The motor(s) replaces the lift wheel. The basic operation is the motor operates a gear assembly which then operates a winch and cabling system. Some of the motor features to take into consideration include:
- Torque (capacity to handle the lift)
- Horsepower (how quickly the lift accomplishes its work)
- Lift capacity
- Power source (AC/DC)
- Ease of maintenance
- Connection style
- Finish – painted, stainless steel or both
Types of Motors
There are different types of motors, of course. We live in a time of choice!
C-Face Motor – The direct drive motor is totally enclosed and works with direct drive boat hoists. It does not work on flat plate belt hoists (see the next section). The drive shaft of this motor installs directly into the gearbox and does not need a belt or pulley.
Footed Motor – The motor works on a hoist that has a belt and pulley. It does not work on a direct drive hoist.
Blower Motor – The blower motor is used on any air operated boat lift or a floating boat lift. It has a motor that is really like a heavy duty vacuum motor to push water out of lift pontoons which allows the pontoons to rise and lift the boat. When ready to lower the boat, exhaust valves allow air to escape and be replaced by water. There are no chains, cables or pulleys in this system.
Boat Lift Drive Systems
The older standard drive system is the open gear flat plate which has been around for over 45 years. It is the least expensive drive unit and easier to maintain because of the open gear, but it is also noisier and can get messier compared to other drive systems because you must keep it oiled. The flat plate gear is turned by a cogged belt installed on the pulley attached to the motor. The belt drives may be covered by hinged covers, though they are not as effective as a totally enclosed system at keeping the elements out of the system.
Today, many boat lifts are direct drive and use a chain drive or a worm drive. The moving parts are enclosed, so they are quieter and require less maintenance. The direct drive uses a gear system to turn a sprocket which operates the winch. The chain drive direct drive system uses a chain to turn the sprocket, while the worm drive gear assembly has a “worm” on a worm shaft that turns a toothed sprocket. These units are enclosed, meaning all the moving parts are in a sturdy housing. The worm drive has the slower rotational speed and higher torque which adds to lift capacity.
The friction drive is also called a wheel-to-wheel drive unit. It has a rubber wheel that turns the fixed-in-place lift wheel to operate the winch and the cabling system. An AC or DC motor turns the wheel.
Cycloidal gearless drives address some of the issues that come with worm drive designs. Worm drives endure a lot of friction, force and heat, creating high power losses. They are slow and can wear out quicker than other gear designs. The cycloidal drive has an input shaft that, from the top, goes through a cycloidal disc set in ring pins and all placed on output rollers and bottom shaft. Turning the input shaft leads to the cycloidal disc moving in a circle which rotates around the roller bearing. The whole operation is based on turning rather than grinding metal components together. Since there are no gears to grind, the drive is less likely to lose teeth, lock up and wear out before its time. It is efficient and has fast lift speed. However, it does require fail-safe brakes. The other drives work slower and do not require brakes.
To learn more about lifts, it may be worth contacting a boat lift service provider near you.