Boat lift incident - near miss

[rgano]

Most of you do not lift anything on boat lifts but center consoles and such if you even have a lift, but I put all 12-13,000 pound of the Frolic on a 20,000-lb Deco lift. Finally, after fifteen months of waiting since the destruction of Hurricane Michael and over a month of on-again off-again barge and worker presence, we put the final touches on the lift allowing me to lift the boat clear of the water. Up it came with no issues and rested about 20 minutes with cradle clear of the water by about a foot while I began preparations to reset the limit switch. I pressed the down button and descent seemed normal, but I wanted to stop the motion for the purpose of clearing the boarding ramp. Both motors stopped, but the port side gear box was humming, and the lift wire rope on was clearly paying out on its own. I tried to hit the up button to get control but only the stbd side responded further heeling the boat over. I then pressed the down button again and watch the race of the unwinding port side against the motorized stbd side. By the time the boat refloated, I would say there was a 15-20 degree list. Had I had it as high as I normally had in the past, I am afraid the cabin of the boat would have been contacting parts of the lift and pier causing lots of damage. I lifted the boat several more times just enough to get its full weight on the cradle, and the same uncontrolled, but slow unwinding of the port wire ropes happened. It did not happen if there was partial weight lifted, but I could clearly see the port motr was taking a bit longer to come to a full stop. The stdb side motor was replaced this month because it got submerged in the attempts to salvage the lift. The port side was never underwater but sat cockeyed for 15 months, and now it seems its brake is gone (even though it hold the full boat weight after being stopped while going up). Another motor will be ordered Monday. Oh, and the supposedly watertight limit switch box was full of rusty water and will be replaced as well. All four wire ropes are brand new. So be wary when stopping your lift when it is traveling in the down direction, especially after a cat five hurricane.

 

[wkearney99]

Yikes, that must've been a butt-clenching moment seeing it keep going.

 

[rgano]

A large monkey wrench on the tubular wire rope reel MIGHT have stopped it, but who has that standing by?

 

[diver dave]

Wow. I believe I’d want a couple brakes on each side.
I had a davit with a gearbox system that would unwind with a load and no power. With most induction motors, they need to stop before their direction can be changed electrically. These systems clearly need very reliable brakes; and not sure that one per side is adequate.

 

[rgano]

I have not spoken to the Deco lift people about this yet because it was late today after business hours when this happened. They are a highly regarded company, and I presumed they use quality engineering. After all, immediately after the hurricane, both motors functioned, even though the whole lift had been blown over at a 45 degree angle. I will be very interested in their take.

 

[wkearney99]

I have not spoken to the Deco lift people about this yet because it was late today after business hours when this happened. They are a highly regarded company, and I presumed they use quality engineering. After all, immediately after the hurricane, both motors functioned, even though the whole lift had been blown over at a 45 degree angle. I will be very interested in their take.

I'd speculate that once a lift has been damaged "at all" by a storm, all bets are off. I'd imagine the lift being off-kilter put stresses on areas not designed for it and thus contributed to the brake failure. That or moisture damage from not being in a normal orientation.

 

[rgano]

I think you're right, and that is why new wire rope was used. Now with the replacement of the motor and or gearbox on this problem side and a new limit, all critical moving parts are replaced. Pulleys on the cradle were all disassembled and in excellent shape due to my assiduous grease schedule.

 

[Wayfarer]

Today I learned the word "assiduous."

I'm glad your boat didn't tip over.

 

[rgano]

I was forever getting into it with my use of quarter sized words when writing naval messages. They may have had a point what with all the "hits" our long haul communications used to take before satellites. Assiduous might end up being ass u is or some such thing. I could ter 'em up today with the precision of today's satellite comms!

 

[wkearney99]

I think you're right, and that is why new wire rope was used. Now with the replacement of the motor and or gearbox on this problem side and a new limit, all critical moving parts are replaced. Pulleys on the cradle were all disassembled and in excellent shape due to my assiduous grease schedule.

Heh, that got a chuckle. We had vocabulary cards in 8th grade catholic school That was among them. But hey, at least we got a decent vocabulary while the rest of their attention was inflicted upon us.

 

[RT Firefly]

Greetings,
Mr. wk. I don't think vocabulary cards would be politically correct now-a-days. Not fair to the illiterates in grade 8.

 

[rgano]

After a conversation this morning with the lift manufacturer, I tightened the new vee-belt on the side of the lift doing the freewheeling after stopping the lift while in the down mode. While the offending side continues to unwind for about 2-3 seconds longer than the side with the new motor, that is the extent of the issue for now, and the boat is in the lift again after 15 months. Yippee.

Because both the motor and gear pulleys rolled along together when the freewheeling occurred, I was doubtful that simple tightening a vee-belt would solve the problem, but hey, I can't argue the results.

Nonetheless, I will be installing a new motor along with the rusted out limit switch this week. I will take the original motor to a local shop to have it gone over in detail and then placed in the ready spares locker in my shed.

Now if I can just get somebody to build a roof over this goat rope.

 

[diver dave]

You should not tolerate uncommanded lowering of 13k pound boats. Especially if each side has a mind of its own. Sorry. This install needs positive brakes. Power off, and the shafts are held.

I had one lift designer tell me to use grease instead of 90w oil in the gearbox to lessen to freewheeling effect. Possible. Also, as your gearboxes wear in, the gear/bearing preload is lessened, and the drop will increase.
So, if a v belt breaks, or someone decides to replace it, half the boat will fall down?

 

[rgano]

An excellent way to steal this boat would be for two malefactors to simultaneously cut the belts.