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

 

[eureka]

280474. Please supply the following additional information. Does the barge have a front rake? If so what is the dimension? Does it have a rear rake? If so what is the dimension? Is the offset of 1.6 meters on the longitudinal center line? Is the offset of 1.6 meters to the rear of the transverse center line? Will the lift be from the side of the barge or from the rear of the barge?

 

[kander]

Extreme caution. Crane mounted on barges that were never designed to go offsore can be a risky business. As the crane slews with a load, then the balance of the barge will shift. If you are deploying to depth then you will have to take into account Dynamic Applification Factors, or DAF as it is known. This is where swell and waves effect the inertia of the load and so ramping the weight up. Also, is the crane to be fixed to the barge?

I would downrate the crane to a factor of x0.6, before you do any analysis.

Hope this is of help.

 

[AngelAlvarez]

I do not have all the details but check if there are any tanks to be used to balance the barge during loading and also check at what angles you will take the cargo load and unload it . As kander pointed out it is risky business and before putting any load on it just calculate the angles of inclination you will get from certain tonnage at certain angles relative to the center line of the barge. Check very carefully what will be the significant wave - period, lenght and heigth as the waves not only moves the cargo but also change the moments resulting from the displacement of water and the weight of the crane and barge.
The crane should be attached to the barge to avoid any movement during transportation and operation. Just be carefull. If you can't make it, I will need more details to be able to help in depth.

 

[carterinms]

What regulations does the barge conform to? ABS has stability requirements for crane barges. If you are concerned about the lift, ask for a copy of their calculations.