FROM THE BoatU.S. INSURANCE FILES BY BOB ADRIANCE
BOAT-LIFT BLUES AND FALLING BOATS
Protecting your boat when it’s on its lift is up to you.
The devices are workhorses, but have their limits
SEVERAL YEARS AGO, a retired gentleman in Fort Myers, Florida, got some really bad news from his neighbor: “Your boat is sinking.” Fortunately, the boat was next to its lift, so rather than hassle with emergency pumps, all the owner did was press the lift’s “up” button and wait; the boat’s salvation was at hand, or so he thought.
The lift’s motor whirred away and the boat, with thousands of pounds of water still trapped in
the hull, rose oh-so-slowly out of the water. Then, just when the owner was reaching to shut
off the lift’s motor, there was a loud snapping noise, and in an instant the lift and boat were
plunged back into the water. The boat landed on the twisted metal stump of the just-departed
strut, punching a hole in the hull. Before he could find an emergency pump, the boat sank.
The owner learned a tough lesson about his boat’s lift: The rated capacity (usually on a
label) is its lifting capacity. A lift rated for 6,000 pounds, for example, is not designed to lift
boats that weigh 6,100 pounds; there have been claims for lifts that failed when torrential
rains or snow added considerable weight to a boat. Besides the lift itself, there are several
other ways a boat hoist can fail. The most common, according to the BoatU.S. Marine
Insurance claim files, involves cables that fatigue and break, either because of misalignment,
chafe, corrosion, or a combination of all three.
Excessive chafe on the cable is typically caused by faulty sheave alignment, incorrect
sheave groove diameter, or improper drum
winding. Sheave alignment can be inspected
easily by looking down the cable to make
sure it’s centered and fits neatly in the
groove. Anything less than dead-on puts
pressure where it isn’t designed to be and
will hasten the cable’s — and the sheave’s
— demise. Misalignment may also cause the
cable to jump out of the sheave.
Nothing lasts forever. Even if the cable glides
smoothly over the sheaves and drum, it still
needs to be replaced periodically. Internal
abrasion occurs whenever strands work
against each other under load. External abrasion occurs when the cable bends around
the winch drums or spindles. How long a