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R/V Sikuliaq
Password to unlock spreadsheet: Sikuliaq
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Crane Side and Axial Loading
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Purpose:
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This spreadsheet is to be used to evaluate the crane boom for use with the ship's winches or
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portable winches mounted to the main deck, with a block hung from a padeye on the crane boom.
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The analysis looks at both the loads in towing and when the package is suspended vertically
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during launch. For a given line tension, the side load will always be greatest during the
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vertical lift stage of the operation.
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This analysis does not check for interferences in leads.
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Assumptions:
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1.
Crane boom is assumed level
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2.
Portable winch lead height is assumed to be 3 ft off main deck
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3.
Vertical tow angle is 45 deg down from horizontal
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4.
Side tow angles is +/- 20 deg from parallel with centerline
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Input:
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In order to calculate the side and axial loads on the boom, it is necessary to establish
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the slew angle of the crane, and location of the wire lead from the winch.
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Conventions
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Slew angle is measured with counter-clockwise as positive angle, with 0˚ aft
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Port crane will have negative (-) slew angles when outboard
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Starboard crane will have positive (+) slew angles when outboard
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Distances are referenced to the center of the crane post
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X (longitudinal) dimensions are positive aft of the crane and
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negative (-) forward of the crane
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Y (transverse) dimensions are positive (+) to starboard of the crane,
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and negative (-) to port of the crane
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See the figure for details
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r is determined from the pulldown list given below. Total length from center
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is calculated from either padeye location or boom end, with a given extension.
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Cells formatted like this designate - Required Input
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Cells formatted like this designate - Results
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Port Crane
Starboard Crane
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Select Radius = Fully RetractedSelect Radius = Padeye
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r = 30ftr = 18.17ft
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 Enter Slew Angle = -45deg Enter Slew Angle = 45deg
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Wire ABL = 36,500lbfWire ABL = 11,100lbf
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Wire ABL limited to 11,100 lbf when using padeye
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Is lead from the fixed winch systems (hydro or oceanographic) or portable?
Is lead from the fixed winch systems (hydro or oceanographic) or portable?
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Select oneOceangraphic WinchSelect onePortable Winch
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If using a portable winch enter location here
If using a portable winch enter location here
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X1p = 0ftX1s = -5ft
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Y1p = 0ftY1s = 15ft
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Allowable Loads
Allowable Loads
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Faxial allow = 105,000lbfFaxial allow = 105,000lbf
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Fside allow = 17,500lbfFside allow = 25,025lbf
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ResultsResults
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LiftingLifting
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Faxial = 34,886
lbf - force along length of boom
Faxial = 8,591
lbf - force along length of boom
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(+) values indicate compression
(+) values indicate compression
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(-) values indicate tension
(-) values indicate tension
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Axial load is below allowable load, OK
Axial load is below allowable load, OK
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Fside = -10,735
lbf - perpendicular to boom
Fside = -576
lbf - perpendicular to boom
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(+) values indicate load acting aft
(+) values indicate load acting aft
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(-) values indicate load acting forward
(-) values indicate load acting forward
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Side load is below allowable load, OK
Side load is below allowable load, OK
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TowingTowing
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Faxial = 23,978
lbf - force along length of boom
Faxial = 6,018
lbf - force along length of boom
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Fside = 12,656
lbf - perpendicular to boom
Fside = 4,942
lbf - perpendicular to boom
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Axial load is below allowable load, OK
Axial load is below allowable load, OK
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Side load is below allowable load, OK
Side load is below allowable load, OK
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