Barge Mounted Crane

[280474]

Dear All,
I have a bidder's document to be reviewed regarding the subject. They offer a barged mounted crane with the following specification :
Barge Dimension = 150' x 50' x 10', draft=4.5' completed with ballast system
Crane = Crawler Manitowoc 4100 (Serial 41383) with LaticeBoom 200T capacity (Boom Length = 150ft and 180ft)

According to its load chart, the crane barge is able to lift safely 42 Tons of load at 45' working radius (150 ft boom length and 76.8 deg angle)with crawler extended.

Looking to the layout of crane barge, actualy the crane is not located at the center of barge. In fact, it is located 1.6 meters from barge center line.

What I need from you guys, if you ever have experience using such as barge mounted crane, please share to answer my question.... is it possible to lift 42T of load at 45' working radius with that specification and layout..?

Looking forward for your response

 

[a1a1a]

According to the specification given, The crane is not situated at the centre line.It is situated at 1.6meters (approx.5.25')from the centre. This will affect the boom length of the crane and the contact angle between the crane boom and the load.
For the crane to lift 42T load at a heigth of 45', It needs a heigth of more twice the load heigth as to overcome the load heigth and to be able to slide out from its position.
Therefore with respect to the specification given and also the deviation of the crane position from the centre line of the barge and the effect of the angle of contact, the crane cannot lift a 42T load at a heigth of 45'.

 

[a1a1a]

According to the specification given, The crane is not situated at the centre line.It is situated at 1.6meters (approx.5.25')from the centre. This will affect the boom length of the crane and the contact angle between the crane boom and the load.
For the crane to lift 42T load at a heigth of 45', It needs a heigth of more twice the load heigth as to overcome the load heigth and to be able to slide out from its position.
Therefore with respect to the specification given and also the deviation of the crane position from the centre line of the barge and the effect of the angle of contact, the crane cannot lift a 42T load at a heigth of 45'.
Regards,
Albert.

 

[McNavy]

I work with barge mounted cranes all of the time and I rely on the USACOE rules for crawler cranes on a barge deck. Generally, you cut the rating in half for the crane. Why? The table that came with the crane is for flat surface/land applications and does not account for the trimming of the barge as you make the pick. The other reason is that the operator cannot "feel" the back end of the crane lift when he starts getting close to the limit. A good marine contractor will know this, but it will be up to you to enforce it. I know this is late, but file away for future info.
V/R,
John

 

[malaycobra]

Manitowoc provide "list charts" for their cranes when used on barges. They assume an out of level crane.

Call a dealer and ask.

De-rating a crane by 50% is very conservative.

Also waiting for the crane to tip to know when yo have reached it's limit is EXTREMELY DANGEROUS!

Also, to a1a1a, the post refers to a 45 foot RADIUS, not lift height.

 

[10538]

to add to McNavey's comments

Things don't always get enforced. Make sure you CYA (cover your arse)

I worked for a place that tipped a crane mounted barge. It was a 4 legged lifting barge. They capsized the barge and bent one of the legs like wet spagetti!

 

[explojayhawk]

Having been a part of several crawler and fixed derrick lifts (upto 2,000 tons), I only notice that sea state is not mentioned here. If in a location where this may occur, a maximum state needs to be determined (along with wind).