Page 379 - Introduction to Marine Engineering

Appendix

The appendix is reserved for all those topics which, although very useful,
do not quite fit in elsewhere. As an introduction, or a reminder, a section
on SI units (Systeme International d'Unites) is given together with some
conversions to the older system of Imperial units. Various engineering
calculations relating to power measurement and fuel consumption are
explained, together with worked examples. So that the production of
manufacturing drawings of a fairly simple nature can be accomplished,
an introduction to engineering drawing is provided.

SI units

The metric system of units, which is intended to provide international
unification of physical measurements and quantities, is referred to as SI
units.
There are three classes of units: base, supplementary and derived.
There are seven base units: length—metre (m); mass—kilogram (kg);
time—sound (s); electric current—ampere (A); temperature—keivin
(K); luminous intensity—candela (cd); and amount of substance—mole
(mol). There are two supplementary units: plane angle—radian (rad);
solid angle—steradian (sr). AH remaining units used are derived from
the base units. The derived units are coherent in that the multiplication
or division of base units produces the derived unit. Examples of derived
units are given in Table A. 1.

Table A.I Derived units
Quantity Unit
Force Newton (N) = kg.m/s 2
Pressure Pascal (Pa) - N/m 2
Energy, work Joule (J) - N.m
Power Watt (W) -J/s
Frequency Hertz (Hz) = l/s

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