mar2012 introduction 2011 block breakdown

Paul Stott

Hossein Enshaei

February 2011

MAR2012 Engineering applications

Agenda

• Statement of the coursework

• Product breakdown and shipyard layout: Paul Stott

• Process analysis: Hossein Enshaei

• Questions

Block breakdown

Modern shipbuilding divides the ship into blocks.

Block breakdown

• This is a typical block, leaving fabrication ready for erection on the building

berth.

Ship construction processes

Don’t forget that some means is necessary to get the block

to the erection site

Ship construction process

• This is what the erection of blocks in a building dock looks like when it is

very well done.

Block breakdown

How is the block breakdown decided on?

Shipyards strive for the largest practical block at

the erection stage.

Why?........

Block breakdown

0

2

4

6

8

10

12

12

4

8

12

Relative cost of work (manhours) by stage of construction

Block breakdown

Fewer manhours are needed at earlier stages of

production because:

• Supply routes are short

• Access is open and easy

• Crane accessibility is good

• Work can be done “down-hand”

• Staging is unlikely to be required

• Conflict with other work will be minimum

Block definition in shipbuilding

How is the block breakdown for a ship determined?

Constraints and considerations:

• Blocks should as far as possible be self-supporting

• Where possible temporary bracing should be avoided

• Unit breaks should be away from major elements of structure

• Blocks should take account of functional zones

• Maximise the final lift (maximum weight – including outfit)

• Capacity of transport from steel shop to blocking area

• Door dimensions from steel shop

• Workstation dimensions within steel shop

• Blocking area workstation dimensions

• Crane heights

• Other constraints?


How is the block breakdown for a ship determined?

Further considerations:

• Blocks will have a leading edge and a trailing edge

• The leading edge should be relatively rigid – for example close to

a bulkhead: this will ensure maximum stability (i.e. Maintaining

the shape) of the steel until the next block is added

• The trailing edge should be relatively flexible to allow for fairing

• If “green” material is used it should be on the trailing edge

15 20 25 30 35 40

Considering the equipment functional

arrangements define the block breakdown for

both steel and outfit.

Lower zone configuration

Outfit Block Breakdown

As far as possible keep block

breaks clear of equipment

15 20 25 30 35 40



Define the outfit units

installed on steel blocks

prior to erection

As far as possible keep block

breaks clear of outfit unit boundaries

15 20 25 30 35 40

Define the outfit units to

be installed “blue sky”

after block erection



Ensure that the erection sequence

enables straight-lift unit installation

15 20 25 30 35 40



Define accessway and services

route assemblies installed on

steelwork blocks

Ensure that services routes are contained

within steel block boundaries

Steel production

Blocks are the ultimate product of the steel shops.

How are the blocks built up?

Steel manufacture processes• Assembly: the hierarchy of stages

The following diagrams are by kind permission of Malcolm

Bell Associates (Malta)

3D solid model

2 Blocks (P&S)

CAD model exploded at second level

Block assembly analysis

1 Blocks = 4 units + 4 sub assemblies

CAD model Block Breakdown

Unit definition

1 Unit = 5 sub assemblies

Steelwork processes

OU

TF

T IN

STA

LL

AT

ION

• Treatment (shotblasting & priming)

• Cutting / marking

• Forming / shaping

• Welding

• Painting

• Storage, transport and marshalling

Outfit installation

It is essential to productivity and competitiveness that

outfit work and steelwork are integrated as far as

possible and that outfit items are fitted at the earliest

possible stage

Piece parts

Minor assembly

Sub assembly

Unit assembly

Block assembly

Ship

OU

TF

IT IN

STA

LL

AT

ION

Outfit installation

Outfit installation stages by increasing cost

On sub-assembly

On Unit

On Block: open sky

On Block: closed

On Berth: open sky

On Berth: closed

Post-launch

Cost increases

because of more

difficult access and

more difficult working

conditions

Outfit installationIt is essential to productivity and competitiveness that

outfit items are installed in units or assemblies

wherever possible, rather than piece by piece.

Optimum ease of access and least cost in a workshop

environment

Outfit manufacture workshops

• Pipe shop

• Machine shop

• Sheet metal shop

• Electrical shop

• Stores

Don’t forget painting

Shipyard layouts

A layout is on Blackboard for you to look at –

• Yanbu al Bahr (note – this is a large yard and

includes repair as well as newbuild)

Contact details:

Office: On mezanine floor behind LT1

email: [email protected]

mar2012 introduction 2011 block breakdown

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