Jackup Definition:

Here, we have two samples of jackups - a "standard" three leg jackup and a mat jackup. The data files for each is similar in that once the jackup exterior and "spud cans" are defined, the remainder simply defines items which will attract wind and down flooding points. The command files for both do basically nothing but plot pictures of the system and compute hydrostatics. The real difference between the two is the definition of the hull and the "cans", and these will be discussed below.

The important thing about these samples is that once the model is completed, each of the movable pieces can be moved with a single command during the analysis.

• 3 Leg Jackup
• Mat Jackup

Three Leg Jackup:

• 3 Leg Jackup Hull generation commands
• Hull Generation log
• Hull Generation results
• 3 Leg jackup data
• 3 Leg jackup commands
• 3 Leg jackup log
• 3 Leg jackup output

This sample is a "standard" three leg jackup. The hull of this jackup is complicated, and the model is generated in the &SURFACE Menu using the file jh_gen.cif. Basically, the hull consists of

• A basic hull,
• Leg Wells cut from the basic hull,
• Thruster tunnels added to the basic hull, and
• A crane pedistal added to the basic hull

We begin by defining the "blocks" which will be used to make the finial hull: BASIC_HULL, PORT_LEG, STRB_LEG, AFT_LEG, CRANE, P_THRUST, S_THRUST, RACK1, RACK2, and RACK3. All of these are defined "simply" with planes and offsets except the thruster blocks. Each of these is formed by combining three blocks.

Once we have the basic blocks, the rest is simple: find the

• Difference BASIC_HULL with each leg well,
• Difference with each rack cutout,
• Union with the crane pedistal
• Union with each thruster

For this example, the legs all have the same type of Spud Cans and these are defined with "PGEN" blocks in the macro CAN_MAC at the top of the data file (Click Here To look at it)

Mat Jackup:

• Mat Jackup Hull generation commands
• Mat Jackup Hull Generation log
• Mat Jackup Hull Generation results
• Mat Jackup Mat generation commands
• Mat Jackup Mat Generation log
• Mat Jackup Mat Generation results
• Mat Jackup data
• Mat Jackup commands
• Mat Jackup log
• Mat Jackup output

The Mat Jackup sample is different from the three leg example in that, with a mat, all legs must move together. Thus, only one leg can have a "can" which is the mat. The mat itself is complicated. It is composed of several compartments some of which are always flooded and some of which are always buoyant. For damage stability, we will want to flood the buoyant ones. Thus, the mat generation file (Click Here to view it) will emit compartments as well as an exterior. The definition of the exterior is similar to that for the three leg jackup (Click Here to view it), so we will not give a blow by blow descrtiption of it. The mat, on the other hand has another interesting feature - for the mat to move with the legs, it must be in the same part as the leg to which it is attached. This is accomplished by using the command

   emit @  -part leg_cb