Crane goes crazy and I'm lucky

[RickyD]

My "davit" or crane is both hydraulic for arm up and down plus an electric winch. A couple years ago I put a new Warn 1000 lb lift motor to lift my 800lb dinghy. Yesterday, I lifted my dink out of the water. Swung it aboard on the bow and down onto its support rails. I disconnected the hook, lowered the arm, and attached it to its deck eye. Then the excitement. I hit the up button to tension the cable and it did not stop when I released the switch. Nor when I quickly hit the down function. It pulled the arm down hard and into my inflatable until my 1/4" dyneema cable snapped. It all happened so fast all I could do was mess with the hand help switches. When it broke, the pressure from the inflatable blasted the arm into my leg. Nasty Charlie horse. The lift motor kept running. I quickly unplugged the control cable. Motor kept running. I ran down below and hit the breaker. Wow, if that had happened earlier I could have been lifting the boat a little to resettle it on the rails and it would have dropped the boat onto the deck and/or me. Or, earlier it would have dropped in the water and have the weight ding the dink deck. I have not checked it out yet. That was crazy!!!

 

[READY]

Valuable lesson learned,thanks for sharing. Perhaps push buttons are less than ideal since they can get stuck in closed condition (sounds like that was the peoblem)? Maybe the contacts fused or a relay stuck? I never have considered it before but now am glad I have a socket/plug setup so I can fully disconnect the power right at the crane. My up down switch is also a big industrial rotary knob setup which is not elegant but I now respect it more.

Dynema is very strong stuff. Surprised the breaker did not flip with that much load? Maybe drop that down?

 

[smitty477]

Valuable lesson learned,thanks for sharing. Perhaps push buttons are less than ideal since they can get stuck in closed condition (sounds like that was the peoblem)? Maybe the contacts fused or a relay stuck? I never have considered it before but now am glad I have a socket/plug setup so I can fully disconnect the power right at the crane. My up down switch is also a big industrial rotary knob setup which is not elegant but I now respect it more.

Dynema is very strong stuff. Surprised the breaker did not flip with that much load? Maybe drop that down?

The OP's description describes a relay failure - not related to the 'push buttons'.

 

[RickyD]

At the moment it happened I was all packed and leaving the boat so I did not do anything beyond scheduling my electrician to go over this with me and another small project. When I get back to the boat I'm going to turn the breaker on and see if the winch motor turns on again. If it does the problem must be with the old solenoids which are mounted inside the forward berth near the base of the crane. There is one for up and one for down. If it does not turn on then I'm guessing that the problem may have been in the hand held remote switch control. So if a switch failed to release and it kicked in the up solenoid, maybe that solenoid would keep that connection even after I unplugged the control cord? I'll replace the two momentary switches and check the wiring. I'll also check the wiring where the remote control plugs into the crane. It uses a large round plug like you would find on a car for towing a trailer with lights and brakes. It is identical to the ones I have been using in that capacity for years. In fact I'll pick up a new one the an auto parts store on the way. I replaced those up and down solenoids in my other crane with a new one that has the up and down function in one solenoid plus it has a wireless remote as well as the wired hand held. It is really nice to not be tethered to the crane when taking a dink off the hard top by myself. I can control it all the way down even at the swim step. I guess I'll buy another one of those also.

 

[Pete Meisinger]

And people ask why I do not like electronic steering or electrical accelerator pedals on my car.

pete

 

[C lectric]

Actually, if I understand RickyD's description of the winch goof up it had nothing to do with electronics. I too am not a great electronics fan but in this case I will put the blame on simple older fashioned electrical equipment which also has a failure rate and can do this.

Relays can weld contacts closed. Pay attention if there is the least hesitation of the action on either up or down which may indicate a relay OR a control switch giving you a warning of brewing trouble. ie welding contacts or burning open of contacts. Either way a failure brewing.


Even the push buttons can fail and weld the contacts.
Larger heavier duty relays and push buttons may/should help so examine all of the electrical control parts for current capacity and duty rating and consider replacing with heavier units which should far outlast what you have.

I will also comment that the closer the rating of the lifting equipment is to that of the load the shorter the life cycle will be. THis may be where you got caught with a 1,000 lb load rating vs an 800 lb lift. Enough capacity but not enough for long term, frequent stop/starts.

This operation would also , likely, have been subjected to frequent starts/stops for positioning of the load which may have sped the contact failure/welding.

THe new motor may have been up to snuff but maybe not the older electrical any longer.

Just some thoughts.

 

[Comodave]

I think I would be adding a quick power disconnect at the crane in case it ever happens again. Gotta love it, now every time you use the crane you will be holding your breath…

 

[Simi 60]

It's why I like our davits with hand cranked $70 trailer winches

At some stage it had been rigged with electric, obviously changed back for a reason

 

[RickyD]

It's why I like our davits with hand cranked $70 trailer winches

At some stage it had been rigged with electric, obviously changed back for a reason

Although I never tried, lifting an eight hundred pound dinghy up and over the rail with a hand crank doesn't sound fun, especially when you need to switch from up to down and back under load.

 

[Portage_Bay]

Although I never tried, lifting an eight hundred pound dinghy up and over the rail with a hand crank doesn't sound fun, especially when you need to switch from up to down and back under load.

Yes with a typical trailer winch it's hatch to change directions under load safely. A worm drive gear winch solves that problem. But it doesn't solve the amount of manual labor to be done. I get around that by using a cordless drill motor.

 

[rgano]

I have a 12,000-lb boat sitting in a 20,000-lb rated lift. Not sure how they came up with 20K, but the 12 wires holding up the cradle (upper and lower sheaves at all four corners of the cradle) are 5/16 SS at around 9,000-lb breaking strength. Maybe the 5:1 safety factor was worked into the 20K designation. We have had the hoist versus winch discussion ad nausea here before, but I vote hoist for lifting dinks.

Last week my lift motors refused to automatically continue to run for more than 20 seconds once the up button was pushed. Discussion with the controller company engineer ended up with me replacing the controller's push buttons (a film which just peeled off the controller panel's surface), a 20-dollar part. He figured an aged button could be the issue. That and my resetting the limits switches cams, has it running OK.

A career at sea during which I saw several potentially fatal breakages during lifts and at-sea replenishment had people not been warned away from dangerous areas left me with a few dictums. Always expect the worst during a lift. Never allow anybody or any body part in line with a wire under strain or under a lift. Never trust a limit switch and have a hand on the power source switch.

Whenever raising my boat into the shed, I watch the highest part of the boat, have a finger on the stop button, and the other hand is on the circuit breaker.

 

[hollywood8118]

It's why I like our davits with hand cranked $70 trailer winches

At some stage it had been rigged with electric, obviously changed back for a reason

Do you also hand crank your windless? and do you hand crank the starter on your genset and main engine?.


The same "basic" design of solenoids are on all those AND most electric winches.


There is nothing wrong with these devices, typically the flaw lies in their maintenance or lack there of.


I understand some don't have faith in the voodoo in electronic devices mostly because they do not understand how they are built. I doubt hardly a car in built anymore without fly by wire control. I personally was in a car accident ( as a passenger in a buddies 69 camaro years ago when the throttle linkage stuck at wide open so even a simple linkage can fail.
HOLLYWOOD

 

[Simi 60]

Yes with a typical trailer winch it's hatch to change directions under load safely. A worm drive gear winch solves that problem. But it doesn't solve the amount of manual labor to be done. I get around that by using a cordless drill motor.

Thanks for the heads up
Didn't know they existed
Will definitely be looking at getting a couple

Best of all worlds
No wiring to run or motor out in weather
No effort to use
Safe
And cheap.

 

[RickyD]

Ok, update: I'm on the boat now and when I activated the breaker, the winch motor started so that means it is the solenoid that stuck. Makes sense. I ordered a new Up/Down 500A solenoid with wireless remotes. I can still use the hand held tethered control but the wireless is nice. Just like I put on my other crane.

Ok, I'm back to an unanswered question. Is it a crane or a davit?

 

[Simi 60]

Do you also hand crank your windless? and do you hand crank the starter on your genset and main engine?.

No, but I can manually crank the windlass if needed
And I carry a spare starter for the main engine
I can live without the genset if needs be, big solar

There is nothing wrong with these devices, typically the flaw lies in their maintenance or lack there of.

What maintenance do you do to a solenoid or starter motor?

Having them crap out miles from anywhere is the issue for me
Manual where I can, spares where I cant

 

[rslifkin]

What maintenance do you do to a solenoid or starter motor?

Make sure connections stay clean, dirt, water, etc. isn't getting into places it shouldn't. Not really much maintenance to do, but anything better than totally ignoring it will generally give a longer lifespan. And of course, if it's an important system without a manual backup, carry spare parts (or be sure you can get them quickly).

 

[BBS]

I have a 12,000-lb boat sitting in a 20,000-lb rated lift. Not sure how they came up with 20K, but the 12 wires holding up the cradle (upper and lower sheaves at all four corners of the cradle) are 5/16 SS at around 9,000-lb breaking strength. Maybe the 5:1 safety factor was worked into the 20K designation. We have had the hoist versus winch discussion ad nausea here before, but I vote hoist for lifting dinks.

Last week my lift motors refused to automatically continue to run for more than 20 seconds once the up button was pushed. Discussion with the controller company engineer ended up with me replacing the controller's push buttons (a film which just peeled off the controller panel's surface), a 20-dollar part. He figured an aged button could be the issue. That and my resetting the limits switches cams, has it running OK.

A career at sea during which I saw several potentially fatal breakages during lifts and at-sea replenishment had people not been warned away from dangerous areas left me with a few dictums. Always expect the worst during a lift. Never allow anybody or any body part in line with a wire under strain or under a lift. Never trust a limit switch and have a hand on the power source switch.

Whenever raising my boat into the shed, I watch the highest part of the boat, have a finger on the stop button, and the other hand is on the circuit breaker.

Might be a bit of thread drift, but this got me thinking.....when my new to me boat was hauled out for survey, I cringed as I observed several people milling about under the boat, as it hung in the slings. I was taught to NEVER stand under a suspended load, but from the hull surveyor to the guy that pressure washed the hull, to the broker.....it all seemed like business as usual. What am I missing?

regards,
Brian

 

[Portage_Bay]

You're not missing anything, they are. Proper training and the observance of basic safety procedures. It's too easy to let time and $$$ pressures make people take chances they shouldn't take.

In decades on the water I've seen very few loads dropped. Rigging failures, wire failures, hydraulic failures and operator error. They all had two things in common. There was no warning. I happened far to fast to get out of the way.

Might be a bit of thread drift, but this got me thinking.....when my new to me boat was hauled out for survey, I cringed as I observed several people milling about under the boat, as it hung in the slings. I was taught to NEVER stand under a suspended load, but from the hull surveyor to the guy that pressure washed the hull, to the broker.....it all seemed like business as usual. What am I missing?



regards,

Brian

 

[hollywood8118]

Might be a bit of thread drift, but this got me thinking.....when my new to me boat was hauled out for survey, I cringed as I observed several people milling about under the boat, as it hung in the slings. I was taught to NEVER stand under a suspended load, but from the hull surveyor to the guy that pressure washed the hull, to the broker.....it all seemed like business as usual. What am I missing?

regards,
Brian

In our local marina the keel gets a couple blocks placed prior to anyone going under the boat, except for the block placer.
HOLLYWOOD

 

[RickyD]

Ok, now that I have determined that the solenoids need replacing and I have one on order, it was brought to my attention that the added strain should have tripped the breaker. Well, on my boat the hoist motor breaker is also the windlass 130A breaker. Should I change that so the hoist has its own breaker at, lets say, 50A?

Still no one weighs in on the davit vs crane question.

 

[Northern Spy]

A davit is a type of crane. A crane is not a type of davit.

 

[READY]

Two big motors on one breaker

Yes I would highly suggest you should move to a second circuit breaker. I would try to match the breakers to the motor AND be sure the wiring is also properly sized. The breaker should trip before the wiring overheats and in case the motor overloads. It is probably a bit of a guess to determine how to size the breaker. I would presume the motor has a load profile where it pulls more current as load increases. You don't want nuisance tripping but you also want it to help prevent a reoccurrence. I would try to find a point that is significantly higher than your actual dinghy lift load (with some upside for variations, some dynamic change in the load due to swells, etc) but well below the max draw of the motor when beyond it's rated load spec. Just as an example lets say it draws 15 amps "nominally" but could draw 30 amps if it is at 100% of its capacity. Unless you need that 100% capacity (and maybe then you should think about increasing the motor) I would put in a 25A breaker. That would give you some headroom and knowledge that if it is tripping something might not be right. That could be a bunch of gear left in the dinghy, something binding or possibly loose contacts creating high resistance. I think you could use a low cost, non-contact multimeter to determine the current draw in normal use. I am actually going to try this on my next launch/retrieval as it would be good to have a baseline. Just by adding some "stuff" to you dinghy you could measure the amp draw and come up with a comfortable rating for the breaker (but still making sure the wiring is sized properly and the amp draw is reasonably close to what the data sheet says you should expect).

 

[Simi 60]

If it's an arm that moves it's a crane AFAIK

 

[RickyD]

A davit is a type of crane. A crane is not a type of davit.

What about those devices that hook the dinghy onto your swim step. Everyone calls those davits and they are definitely not a crane.

 

[Northern Spy]

What about those devices that hook the dinghy onto your swim step. Everyone calls those davits and they are definitely not a crane.

When is a davit not a davit? When it is a snap davit. Sorry, I can't account for the Weaver companies perversion of the word.

 

[hmason]

The 1,000# rated winch is too small for an 800# tender. The 1,000# is rated for a straight horizontal pull. Once you change to a vertical lift and your dyneema travels over a sheave you have reduced the winch’s capacity dramatically. I would urge you to replace the winch with at least a 2,500# capacity.

 

[GoneFarrell]

Ricky,
See if you can find data for the stall current and running current in amps of the winch motor you have, maybe contact manufacturer. Breakers trip on a current/time curve. or measure with a clamp on current meter.

I think you are on the right track with contactor rated for 500 amps, that's the best place to break the working current. Consider the panel breaker protects from fault current in the wires or load, not necessarily motor stall current.

Edit: I missed Ready's comment #22, that is good and along the lines of my thinking too.

 

[RickyD]

The 1,000# rated winch is too small for an 800# tender. The 1,000# is rated for a straight horizontal pull. Once you change to a vertical lift and your dyneema travels over a sheave you have reduced the winch’s capacity dramatically. I would urge you to replace the winch with at least a 2,500# capacity.

Sorry to disagree but my Warn DC1000 is rated as a 1000lb hoist.

 

[RickyD]

Yes I would highly suggest you should move to a second circuit breaker. I would try to match the breakers to the motor AND be sure the wiring is also properly sized. The breaker should trip before the wiring overheats and in case the motor overloads. It is probably a bit of a guess to determine how to size the breaker. I would presume the motor has a load profile where it pulls more current as load increases. You don't want nuisance tripping but you also want it to help prevent a reoccurrence. I would try to find a point that is significantly higher than your actual dinghy lift load (with some upside for variations, some dynamic change in the load due to swells, etc) but well below the max draw of the motor when beyond it's rated load spec. Just as an example lets say it draws 15 amps "nominally" but could draw 30 amps if it is at 100% of its capacity. Unless you need that 100% capacity (and maybe then you should think about increasing the motor) I would put in a 25A breaker. That would give you some headroom and knowledge that if it is tripping something might not be right. That could be a bunch of gear left in the dinghy, something binding or possibly loose contacts creating high resistance. I think you could use a low cost, non-contact multimeter to determine the current draw in normal use. I am actually going to try this on my next launch/retrieval as it would be good to have a baseline. Just by adding some "stuff" to you dinghy you could measure the amp draw and come up with a comfortable rating for the breaker (but still making sure the wiring is sized properly and the amp draw is reasonably close to what the data sheet says you should expect).

I just got off the phone with Warn and there is good news bad news and neither. They do not recommend nor do they sell a breaker for these hoists. They want them directly cabled to the battery. I told them the problem I had and the response was the company line. The bad news is that they no longer make the DC1000 which in a short spool was the perfect size to fit in my Brower crane replacing the old Rule 3300 winch. The smallest they make now is the DC1200. I have not checked the specs but it may be too big for a Brower. So, if your Rule dies, good luck. The DC1000 shows a max amp draw of 87amps. If I did add a breaker, should it be 80 or 90?

 

[rslifkin]

If they're saying not to use a breaker, I wouldn't trust a single bit of advice they're giving. No breaker (or too big) means the whole thing is a fire hazard. Personally, I'd be inclined to try an 80A breaker and see if it trips too easily. It probably won't trip unless you stall the motor. If it does trip, then go for the 90A.