Page 390 - Introduction to Marine Engineering

360 Appendix

This provides the general expression
voyage eons.j /displacement W 8 /speedA 2 voyage distance^
voyage cons.g \displacement 2/ \speed 2/ voyage distance^

Example
A vessel with a displacement of 12250 tonnes burns 290 tonnes of fuel
when travelling at a speed of 15 knots on a voyage of 2850 nautical miles.
For a voyage of 1800 nautical miles at a speed of 13 knots and a
displacement of 14 200 tonnes estimate the quantity of fuel that will be
burnt.
voyage cons.j / displacement \ 2/3 /speeds 2 voyage distancCj
m,, |[|J|_ J uJ T-II—i- i- in i imiiujiii LTim LI ii IT- -nrniui. I m rni nil. ..urir " I ' -iminuiuii TI -ini— i i i I \f I JIITI 1.111.11111111111 I \f 1.11.11111 vimm—T I L J I I I I i rain TI imi—tini'i 11J nirrT-.-..._..
\displacement 2/ Vspeedg/ voyage distance,,
voyage cons. 2
2 3
voyage cons.j _ /14200\ / /I3\ z 1800
290 X12250/ \15/ 2850
voyage cons^ = 1.103 x 0.75 x 0.63 x 290
= 151.14 tonnes

Engineering drawing

Most engineering items defy description in words alone. To effectively
communicate details of engineering equipment a drawing is usually
used. Even the simplest of sketches must conform to certain rules or
standards to ensure a 'language' that can be readily understood.
Some of these basic rules will now be described with the intention of
enabling the production of a simple drawing for manufacturing or
explanation purposes. A drawing produced as a piece of information or
communication should stand alone, that is, no further explanation
should be necessary. All necessary dimensions should be provided on
the drawing and the materials to be used should be specified.
A drawing is made up of different types of lines, as shown in Figure
A.3. The continuous thick line is used for outlining the drawing. The
continuous thin line is used for dimension lines, to indicate sectioning,
etc. A series of short dashes represents a hidden detail or edge and a
chain dotted line is used for centre lines.
To represent a three dimensional item in two dimensions a means of
projecting the different views is necessary. Two systems of projection are
in use, First Angle and Third Angle. The First Angle system will be
described with reference to the object shown in Figure A.4. Three views
are drawn by looking at the object in the directions 1, 2 and 3. The views