Jackups are different from most vessels in that they contain things which may move about. In particular, there are legs which can be raised or lowered, cranes which boom in or out and which rotate, and perhaps a cantilever which slides out over a platform. Although it may not be obvious, MOSES provides the capability to model these things and change their positions as an analysis proceeds. Below, we will discuss a set of macros written to ease the pain of dealing with these details.

With the Jackup Generation Macros, one can define legs, cranes, and a cantilever (with a mast) and move them about during a MOSES analysis. There are three macros used to define things and one to move them about. Also, one can easily define "boxes" which attract wind and have a weight with the command:

      W_BOX BOX_NAME X Y Z LENGTH WIDTH HEIGHT -OPTIONS

and the options are

     -SHAPE SCOEF
     -NO_TBOT
     -WEIGHT WT *NOD1  *NOD2, ....

Here, BOX_NAME is the name of the box, X, Y, Z are the bottom center of the box, LENGTH is the length of the box, and HEIGHT is the height of the box. Such a box will fill the space from X minus LENGTH/2 to X + LENGTH/2, from Y -WIDTH/2 to Y + WIDTH/2, and from Z to Z + HEIGHT. The -SHAPE option allows one to define a shape coefficient for the faces of the box, and -NO_TBOT turns off wind for the Z faces of the box. Finally, the -WEIGHT option allows one to place w weight, WT (bforce units) at the center of the box and map these loads to the list of nodes *NOD1, ...

All dimensions here are in big length units; i.e. feet or meters. To use these macros, put the command:

    USE_MAC V_MODEL

at the top of your data file.

The macro:

    JGEN_INIT  -OPTIONS

MUST BE CALLED before any of the others. Here the options can be used to define the cantilever and mast, and their form is:

    -CANTILEVER  CX CY CZ CL CW CH
    -C_MACRO C_ADDIT
    -MAST MA MX MZ ML MW MH

Here CX, CY, and CZ are the X, Y, Z vessel coordinates of the beginning (farthest forward part) of the cantilever and CL, CW, and CH is its length, width, and height. This defines a simple box. If you wish something else (in addition to a mast), you can define it in a macro, C_ADDIT. When defining cantilever additions, the coordinates you use are relative to the beginning of the cantilever. Finally, if desired, the -MAST option defines a mast at the position, MX, MY, and MX relative to the beginning of the cantilever with a length, width and height (when laying parallel to the cantilever) of ML, MW, and MH.

A leg is defined with the macro:

     LEG_GEN LEG_NAME X Y Z LLENGTH OD -OPTION

and options are:

     -CAN CAN_MAC
     -PERM PERM
     -ID LEG_ID

With no option, this command will define a leg named, LEG_NAME, with a bottom located at X, Y, Z in vessel coordinates and is LLENGTH high and has an outside diameter of OD. If you want a spud can on the bottom of the leg, define it in a macro and pass the name of the macro with the -CAN option. When defining the can, the coordinates you should use are relative to the bottom of the leg; i.e. if you use Z equal zero in defining the leg then the can should have negative Z coordinates when the legs stops at the top of the can. Alternatively, you can specify Z to be the can depth when defining the leg and the can definition starts at zero. If the leg penetrates the can, then both can be defined with from Z equal zero. The pereability of the leg by default is 1, and it can be changed with the -PERM option. If you use the -ID option, then an interior compartment, I_LEG_NAME, will be generated with the same properties as the leg, except that the diameter is LEG_ID. This compartment can be flooded.

You can define a "mat type" jackup by having a "can" on only one leg and, of course, defining the mat to be the can. You can also put interior compartment into the mat which can also be flooded.

A crane can be defined with the command:

    CRANE NAME X Y ZP PED_OD HB CAB_OD  HBC HSC -OPTION

and the option is

    -FACTOR SCALE

This defines a crane named, NAME, with the base of the pedistal located at x, y, zp vessel coordinates. PED_OD is the outside diameter of the pedistal, HB is the distance above pedestal base where the boom is attached, HBC is the height above pedestal base where the cab starts, HSC is the height above pedestal base where the cab stops, and CAB_od is the diameter of the cab. The option can be used to scale the size of the crane.

Once these this have been defined, their position can be changed with the command:

     PART_SET  L1_NAME Z1 L2_NAME Z2 ... -OPTIONS

and the options are:

     -ALL_LEGS Z
     -CANTILEVER X
     -MAST ANG
     -R_CRANE C1_NAME C1_PITCH C1_YAW C2_NAME C2_PITCH C2_YAW .....

Without options, one can set the vessel Z coordinates of any leg by specifying the leg name followed by its height. The -ALL otion allows one to set the position of all legs. If you have a mat type jackup, then you should always change the legs with the -ALL_LEGS option. The -CANTILEVER option sets the beginning of the cantilever at the vessel coordinate X, and the -MAST option sets the angle of the mast to ANG (degrees). To rotates cranes, one used the -R_CRANE option. Here, C1_NAME is the name of the first crane to the rotated and C1_PITCH and C1_YAW are the pitch and yaw angles of the boom.