Vertical Hydraulic Boat Lift - Safety to prevent cradle drop

[TommyTuna]

Hi everyone- I have a new Bertrand Hydro Cable vertical boat lift coming for the new Axis a22.

https://bertranddocks.com/products/boat-lifts/hydro-cable-boat-lifts/hydro-cable-hc8500/

 

I am told in the unlikely event the hydraulics leak/hose damage the cradle will slowly drop and boat could float away

we are often away for weeks at a time and the cottage is on an island. Is there a way I could secure the cradle with a safety chain in one corner to guarantee it won’t drop?  I thought maybe wrapping grade 80 chain around top corner and the cradle could do it vs drilling holes in posts for locking pins.  Just not an engineer so unsure how the chain in one corner would carry load.

All suggestions welcome - thank you!
 

 

[tbullard]

You might be over thinking this. Just add dock lines to the boat while on the lift. If it drops your still good. Just make sure the plug is in before you leave it.

[TommyTuna]

51 minutes ago, tbullard said:

You might be over thinking this. Just add dock lines to the boat while on the lift. If it drops your still good. Just make sure the plug is in before you leave it.

Was thinking that but we get pretty bad storms and waves that could end pretty badly.

[Cole2001]

The likely hood of a failure happening is very slim. Add some dock lines so it doesn't float away and if anything else happens that is why you have insurance. For extra peace of mind you can add a camera on the dock.

[MalibuNation]

Do you have neighbors?  Whenever I leave for an extended period I let my neighbors know where I keep my boat keys and truck keys are in case my lift fails.  Actually we were lifting my boat last August and the cable snapped.

I know you mentioned being on an island so it's not quite apples to apple but could neighbors help?

[TommyTuna]

1 hour ago, MalibuNation said:

Do you have neighbors?  Whenever I leave for an extended period I let my neighbors know where I keep my boat keys and truck keys are in case my lift fails.  Actually we were lifting my boat last August and the cable snapped.

I know you mentioned being on an island so it's not quite apples to apple but could neighbors help?

Yes one neighbor who isn’t up a lot either hence my concern. I will have a camera installed so I can check on it.  Challenge is in a heavy storm in unlikely event cradle did drop, the winds can push so hard where we are that it would likely topple the dock and lift with 4500lb boat tossing around.

In a cantilever hydraulic setup, it is pretty easy to just lock the cradle to the front legs. This hydro cable setup is a bit tricky. I suppose the ideal solution would be to somehow lock the hydraulic piston in the contracted position and prevent it from moving.  

Here is a good animation of how the system works from Shorestation (Bertrand i am getting is virtually identical): ShoreStation Freestanding Hydraulic Lifting Principle - YouTube

 

Edited March 27, 2022 by TommyTuna

[Pilotguy]

23 hours ago, TommyTuna said:

Hi everyone- I have a new Bertrand Hydro Cable vertical boat lift coming for the new Axis a22.

https://bertranddocks.com/products/boat-lifts/hydro-cable-boat-lifts/hydro-cable-hc8500/

 

I am told in the unlikely event the hydraulics leak/hose damage the cradle will slowly drop and boat could float away

we are often away for weeks at a time and the cottage is on an island. Is there a way I could secure the cradle with a safety chain in one corner to guarantee it won’t drop?  I thought maybe wrapping grade 80 chain around top corner and the cradle could do it vs drilling holes in posts for locking pins.  Just not an engineer so unsure how the chain in one corner would carry load.

All suggestions welcome - thank you!
 

 

The chain in one corner would create a lot of strain on the frame in the event of the hurricane you are describing. the whole weight would be concentrated in a small area. Imagine hanging the boat from a chain to the frame.

Locking pins would be a much better concept and much easier to do. Trying to prevent the ram from moving will not be easily accomplished as the force of the boat would be acting on the piston and you would need to overcome that force on a frame not designed for that intention. 
 

You seem to be planning the 100yr storm along with the 100yr flood. The likely hood of the ram failing and at the exact time there being major waves is extremely small. 

If the winds are so strong that it may topple your dock and lift then there’s not really a whole lot you can do cradle dropping or not. 

[Stevo]

+1 for locking pins, 

[TommyTuna]

1 hour ago, Stevo said:

+1 for locking pins, 

Thanks for the great advice. 
Are you guys thinking locking pins at each leg that protrude to catch the cradle - drill holes in each leg and put pins through?

[Stevo]

Yeah, something simply like a handle hitch pin, with a they are cheap $4-5 from tractor supply, 

I guess it depends on the diameter of the post but get ones with the harpin clip attached with a cable 

[Sparky450]

Also, a chain around one corner would not do it. It would need to be at all support points or it will twist the cradle. 

[TommyTuna]

10 hours ago, Sparky450 said:

Also, a chain around one corner would not do it. It would need to be at all support points or it will twist the cradle. 

Makes sense - four posts would need to be secured. Another solution presented by a buddy was to put a high pressure ball valve right at the piston which would prevent any issues from hydraulic pump hoses but not a defective cylinder. I suppose this would also have added benefit of allowing you to lower the cradle and get boat off incase of failure

[TommyTuna]

Manufacturer responded and advised strapping the four corners would be the way to do it using 10000 lb rated ratchet straps (I believe these have 2000 lb working limit).

[Cole2001]

Rather than ratchet strap I would take a HD sling and wrap it around the frame with a large D ring making a loop. You can find various length slings on Amazon. That way if the lift were to fail each strap would be the same length and you aren’t dealing with ratchets. 
 

Not sure which lift you have exactly but if you have posts like in the video link would be super easy to just set the loop on the post every time. Eliminating the need for any D ring or ratchet. 

Edited March 29, 2022 by Cole2001

[lake4life]

I don't know how accurate the animation is that you posted of the lift operation but personally I'd look at some way to pin/lock/block the ram itself from being able to extend.
One ram, one locking point makes it simple. ¯\_(ツ)_/¯   You have to remember that this safety has to be strong but it doesn't have to be that durable (as in taking stress over and over) as it would likely not be
used nor taking any stress for the life of the lift, but only there for that one time in its entire life as a backup to possible failure.  So keep it simple so you aren't over working/thinking
for that one time in 20 years where it actually is needed - as long as it will hold that one possible time.  That's my thoughts on it for what its worth.

Edited March 29, 2022 by lake4life

[TommyTuna]

9 hours ago, Cole2001 said:

Rather than ratchet strap I would take a HD sling and wrap it around the frame with a large D ring making a loop. You can find various length slings on Amazon. That way if the lift were to fail each strap would be the same length and you aren’t dealing with ratchets. 
 

Not sure which lift you have exactly but if you have posts like in the video link would be super easy to just set the loop on the post every time. Eliminating the need for any D ring or ratchet. 

This is a great idea given you want every corner to be at the exact same height.  By HD Sling, were you referring to something like this with a hook?

Keeper (04228) 36" x 2" Premium Axle Strap with D-Ring, Towing Straps & Ropes - Amazon Canada
https://www.amazon.ca/Keeper-04228-Premium-Strap-D-Ring/dp/B00I5HRTU4/ref=sr_1_10?crid=QWSKI62JQE74&keywords=sling+d+ring&qid=1648573135&sprefix=sling+d+ring%2Caps%2C65&sr=8-10

[barefootpaul]

Soft shackles might work well for the four corner approach. No metal rattling around.

 

https://www.amazon.com/VZCY-Synthetic-Breaking-Protective-Compatible/dp/B093B6YGND/ref=sr_1_16?keywords=Soft%2BShackle&qid=1648574581&sr=8-16&th=1

[Cole2001]

2 hours ago, TommyTuna said:

This is a great idea given you want every corner to be at the exact same height.  By HD Sling, were you referring to something like this with a hook?

Keeper (04228) 36" x 2" Premium Axle Strap with D-Ring, Towing Straps & Ropes - Amazon Canada
https://www.amazon.ca/Keeper-04228-Premium-Strap-D-Ring/dp/B00I5HRTU4/ref=sr_1_10?crid=QWSKI62JQE74&keywords=sling+d+ring&qid=1648573135&sprefix=sling+d+ring%2Caps%2C65&sr=8-10

I was thinking just a strap and adding a D ring to connect the loop. Or ideally, if you could just use the strap with one end on top of each post and the other pulled through itself around the frame of the lift. 

https://www.amazon.ca/Keeper-02612-Lift-Sling/dp/B00I5HRFYY/ref=sr_1_6?crid=2SHPIUH6OZXCX&keywords=lifting+sling&qid=1648582252&sprefix=lifting+sling%2Caps%2C136&sr=8-6

https://www.amazon.ca/Shackles-PACK-Ohuhu-Rugged-Capacity/dp/B075M3JT1F/ref=sr_1_11?crid=196B5DCHZJ0R8&keywords=tow+shackle&qid=1648582303&sprefix=tow+shakl%2Caps%2C128&sr=8-11

The bottom just pulling through itself and top just placed overtop. 

[TommyTuna]

both amazing ideas and relatively cheap to do. I like that this can be accomplished with soft webbing instead of super heavy chains. There will be a canopy as well that will be inserted into the four corner posts that will add further stability and rigidness to the lift structure. I believe replacing the pin used to secure the canopy to the leg with something that holds the sling could be perfect.  I'm impressed with the breaking strength of this stuff you each shared!

Many thanks for taking time to brain storm on this!

[TommyTuna]

actually found this neat little bolt on tractor hook setup that could be attached to each post (posts on my model are rectangular).  Bolt to top of each post and then use to hang sling.  i was also thinking this would be good safety setup if ever doing work under the boat.

Amazon.com: Sulythw 3/8" Tractor Bucket Hooks, Grade 70 Forged Steel Bolt On Grab Hook for John-Deere Truck UTV ATV Tractor Bucket Max Break Strength 15,000 lbs (3 Pack) : Automotive

 

https://www.amazon.com/Sulythw-Bolton-Tractor-Hardware-Included/dp/B08B4MHD24/ref=psdc_15737571_t2_B08M3GWSZP