If 4a looked at Topsides Shapes and 4a_1 looked at a One Piece Module Topsides,

4a_2 introduces how Standard Modules as Boxes used whilst 4a_3 shows the current

fashion, (probably) now towards FPSO's and how those Boxes are used.

In 4a General we looked at

the shapes a module may

have to conform with.In

4a_2, Magnus is taken as

the example of a series of

Modules to make up a

Topsides

4a_2 Magnus, Modules (Boxes) required a base to sit on a jacket Module Support

Frame and tops of Modules for a single pick using four point lift. On the Magnus Box

can be seen the Roof "X" shaped stiffening required for such a lift.

4a_2, also shows a Module Box based on an ISO Container, such boxes use a

standard Top Lift Frame and are in size the other end of the scale to Magnus

4a_1 Clair, was a Twin Crane Pick by one barge. The Topsides required a base

structure strong enough to sit on 4 legs, and a top structure for 2 lift points.

Magnus 4a _2 is used as an example to illlustrate the

progression that has gone on between its design time and

later developments as Clair 4a _1 and West Navion 4a _3.

Magnus was a platform of large module boxes sitting astride

a central corridor used for main corridor cabling, hooked

into the Modules Offshore when installed. One level of

Boxes sat ontop of another. This style of design was

conditioned by the Offshore Cranes available with a lift

capability to install them. Being on a large multileg jacket

the option to floatover was also limited. By the time Clair

came along to be installed the lift weight capability of

Offshore Cranes had improved, as 4a _1 illustates The

picture of the Magnus Module Modle shows the "X" beam

shape that must be added to the roof to lift each module.

This model style has developed to that used by West

Navion where multi point lifts with minimal side forces allows

less steel to be used in the Module. Any side forces are

restrained by Spreader Crane Beams which although not in

the Module still add to the crane load lift weight. Lifting

Modules is not only about the weight of the module but

must inclde the rigging.

4a_3 West Navion, had Power Module Boxes for Wartsila Deisels. The box is

somewhat smaller than Magnus and the Floor and Roof steel less as no module sits

ontop. This style of approach is now common in FPSO's as shown in recent concepts

If Magnus 4a _2 is one end of the scale this example using

the ISO Box approach is the other. Each Module (container)

is approximately 100 th the weight of some Magnus

Modules. In this example ISO boxes are stacked together to

form an accomodation block. The Block itself may be the

complete Topsides or it may become a Module to be

incorporated with other Modules into a Topside