The Benefits of a Covered Drive 10

The Benefits of a Covered Drive

There can be little doubt that Mother Nature will ruin machinery if it is not protected properly. A marine environment is particularly harsh and most people realize how damaging corrosion and electrolysis can be to boats. However, few realize just how vulnerable boat lift drive systems are to environmental degradation. The drive system components that are most vulnerable are the motors, gearboxes and the moving parts (e.g. sprockets, chains, belts, etc.). Let’s take a look at what can happen to unprotected drive systems, especially the motors.

General Benefits of a Cover

IMM Quality Boat Lift Cover
IMM Quality Cover

The IMM Quality Boat Lifts covers have been specially designed to protect and preserve the drive components. The covers are made from high-density polyethylene to provide chemical, U.V. and corrosion resistance. The U.V. protection will minimize fading, sun damage and reflect heat from the sun to lower the surface temperature of the drive components, thus protecting the motors from overheating. We use a roto-molding process to make the covers extra thick to provide the highest level of impact resistance and durability. They will protect your drive components from rocks, lures, limbs, aerial assaults from birds, sea salt, and the elements while keeping everything looking new.

Harsh marine environment quickly ruins uncovered drive components

boat lift drives over time

The covers also protect the drive components from grime and grit.  The housing of the gear boxes are made from cast aluminum so exposure to the elements simply affects the cosmetic appearance.  However, the drive shaft from the gearbox is made from carbon steel so that it can withstand the torque.  This drive shaft along with its seals is vulnerable to breaking down in a marine environment and protecting them with a cover greatly extends the life of the gearbox.  In addition, the sprockets and many other drive components require lubrication to allow them to turn easily and to protect them from corrosion.

grit on boat lift motor
How much grit is on the inside of the motor? This much.

Open drive systems allow the weather to wash away the lubrication, necessitating more frequent maintenance with re-application of lubricant, otherwise, the moving parts will make loud noises and will eventually bind.  Open drive systems also allow grit to accumulate on the components which will wear down the sprockets, sheaves and other moving parts much more quickly than when they are protected by a cover.  With all this grime and grit it is a good thing that the IMM Quality covers were designed to be simple to clean using just a mild detergent and water.


There are many kinds of motors, but the types most commonly used by boat lift manufacturers are open drip proof (ODP), totally enclosed (either non-ventilated (TENV) or fan cooled (TEFC)), stainless steel and extreme duty washdown motors.

Extreme Duty Washdown MotorIf you can afford it, an extreme duty washdown motor is the absolute best choice for a boat lift.  All exterior components are made of stainless steel, along with weather resistant seals and all the other internal components are engineered to resist environmental contamination and corrosion.  As the name suggests, these motors are designed to be washed down with a hose while they are running.  The only real problem is that they cost four times more than a good TEFC motor.  Most consumers cannot justify spending thousands of dollars more on their boat lift for these premium motors.

ODP motorsODP motors are just that – completely open to the environment.  It’s like an open door from whatever is outside, to your bearings, windings and other components on the inside.  Dirt, soot, rain, ocean spray, etc., it all gets inside.  Wildlife and insects are especially fond of nesting inside these motors (mud daubers really love them).  These are the cheapest kind of motor on the market and they do not use weather resistant components.  ODP motors are often used on cheap flat plate drives and are a terrible choice if the drive system is not protected by a well-sealed cover.

TENV and TEFC motorsTENV and TEFC are very similar in design.  Although both of these motors are sealed, the gaskets and other materials are not designed to withstand direct exposure to an outside environment.  The main difference between TENV and TEFC is the fan cooling.  Motors get hot while running and the fan cooling extends the continuous runtime before the motor will overheat.  Typically the non-ventilated TENV motors have rated runtimes of 15 minutes, while the fan-cooled TEFC motors are rated as continuous duty (ie. they can be used continuously, 24 hours a day).  TEFC motors are a great, cost-effective choice when used under a cover.

Stainless Steel MotorsStainless steel motors are frequently used on boat lifts that do not have covers (most commonly TENV versions).  What you should keep in mind is that only the exterior housing, capacitor case, and conduit box cover are made from stainless steel.  The internal parts are not.  This is important because water condenses on the insides of non-covered motors as they cool after use.  Therefore, even stainless steel motors have drain plugs to allow the accumulated water to drip out.  So even though the outside of a stainless steel motor may look nice and rust free, the inside components are frequently ruined by the condensation.

Rusty windings, rotor and capacitor from inside an uncovered stainless steel motor

Using a cover essentially eliminates condensation inside a motor.  The cover greatly slows the cooling of the metal, the cover limits the volume of air around the motor and the cover limits the turnover of moist air around the motor by lowering air flow.  To help you understand why covers eliminate condensation, think about your car and how water can condense on it as dew or frost.  Then think about how cars parked inside garages are protected from this condensation.  Even though the garage is not air tight, is not insulated or heated, cars parked in garages do not get frost (in winter) or dew (in summer) on their windshields on the same night cars parked outside do have condensation.  The same scientific principles protect your boat lift drive components from condensation when they are covered.


There are many reasons why owning a boat lift that has a cover for the drive components is a wise idea.  Covering the drive components will protect them from the elements and greatly extend their service life.  A cover will also preserve the beauty of your motor and gearbox in addition to increasing the resale value of your lift.  A good cover improves the overall aesthetics of the lift giving a sleek, clean look compared to the clunky, industrial look of exposed machinery.  Given all the benefits of a covered drive, why would anyone choose to do otherwise?


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