| What are the advantages of a crane vs derrick? | 1. simple operation
2. less labour intensive
3. clear deck operational views
4. clear deck space of rigging
5. versatility with heavy loads, and not required to de-rig
6. 360° slew and working arc
7. faster operation
8. enclosed cabin |
| What are the disadvantages of a crane vs derrick? | 1. high installation cost
2. increased deck space required
3. complex design
4. specialist maintenance required
5. SWL is less than specialist derrick rigs |
| Maintenance schedule for cargo handling equipment | 1. all grease nipples attended to weekly.
2. inspection of ancillary equipment every 3 months.
3. thorough inspection and stripping of equipment mentioned above every 6 months.
4. lifting appliances should be de-rusted, overhauled, and painted every 12 months.
5. ALL EQUIPMENT SHOULD BE INSPECTED BEFORE, DURING, AND AFTER USE. |
| List the advantages of unitized and pre-slung cargo | 1. combines units into one
2. faster handling by forklift and cranes
3. easier to plan the loading
4. easier to secure and discharge = faster operation |
| Describe the union purchase rig (married falls) | -most common type of rig use on general cargo vessel.
-very efficient, this is a rig where a pair of derricks are used in combination
-manoeuvring this rig need good coordination, only experienced operators should be used. |
| List 8 precautions when using a union purchase rig | a)The minimum operating angle of either derrick should be not less than 15° to the horizontal
b)The maximum included angle between the cargo runners must not exceed 120°
c)The outreach beyond the midship breath of the ship should not be less than 4m.
d)Unduly long slings should not be used by stevedores
e)The standing guy must be of adequate strength, the deck eye plate where it is secured must be in an appropriate location
f)Rigging of derricks to be supervised by a competent person
g)Runners should not be permitted to rub against hatch coaming or other structures, fast wear will happen
h)Maximum load must not exceed either 1/3 the SWL of the lowest rated derrick in the pair or absolute maximum of 2.5 tonnes. |
| What are the disadvantages of using union purchase? | -can be used only for light load (1.5 to 2 tons)
-the winchmen must be highly skilled and
experienced
-the derricks cannot be used for «spot loading»
-repositioning the derricks is time consuming |
| What are the advantages of a hallen derrick? | -it is simple compared to a single swing derrick;
-1 man operation for slewing topping and hoisting
-it can operate with a 15 ° list
-it can operate down to 15 ° above the horizontal
-slewing angles as much as 80 °
-deck clear of clutter
-up to 200T capacity |
| What are the advantages of a velle derrick? | -great slewing radius
-more stable to handle container & heavy lifts
-1 man operation
-the T bar helps to stabilize the load and prevent them from swinging
-less clutter on deck compared to standard derrick
-easy to operate
-SWL between 25 & 100T |
