Page 17 - Ship Construction.DJ Eyres 6Ed

Ch01-H8070.fm Page 6 Wednesday, October 18, 2006 6:51 AM
6 Ship Construction
weather with a clean hull and specified load condition. This speed may be a
knot or so more than the service speed.
Unless a hull form similar to that of a known performance vessel is used,
a computer generated hull form and its predicted propulsive performance
can be determined. The propulsive performance can be confirmed by sub-
sequent tank testing of a model hull which may suggest further beneficial
modifications.
--- ใช้เพื่อการศึกษาเท่านั้น---
The owner may specify the type and make of main propulsion machinery
installation with which their operating personnel are familiar.
5. The general arrangement is prepared in co-operation with the owner,
งานห้องสมุด ศูนย์ฝกพาณิชย์นาวี
allowing for standards of accommodation peculiar to that company, also
peculiarities of cargo and stowage requirements. Efficient working of the
vessel must be kept in mind throughout and compliance with the regulations
of the various authorities involved on trade routes must also be taken into
account. Some consultation with shipboard employees’ representative organ-
izations may also be necessary in the final accommodation arrangements.
6. Almost all vessels will be built to the requirements of a classification
society such as Lloyds Register. The standard of classification specified will
determine the structural scantlings and these will be taken out by the
shipbuilder. The determination of the minimum hull structural scantlings
ึ
can be carried out by means of computer programs made available to the
shipyard by the classification society. Owners may specify thicknesses and
material requirements in excess of those required by the classification
societies and special structural features peculiar to the trade or owners fleet
may be asked for.

Purchase of a New Vessel
In recent years the practice of owners commissioning ‘one off’ designs for
cargo ships from consultant naval architects, shipyards or their own techni-
cal staff has increasingly given way to the selection of an appropriate ‘stock
design’ to suit their particular needs. To determine which stock design, the
shipowner must undertake a detailed project analysis involving consider-
ation of the proposed market, route, port facilities, competition, political
and labour factors, and cash flow projections. Also taken into account will
be the choice of shipbuilder where relevant factors such as the provision of
government subsidies/grants or supplier credit can be important as well as
the price, date of delivery, and yards reputation. Most stock designs offer
some features which can be modified, such as outfit, cargo handling equip-
ment, or alternate manufacture of main engine, for which the owner will
have to pay extra.
Purchase of a passenger vessel will still follow earlier procedures for
a ‘one-off’ design but there are shipyards concentrating on this type of