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comparatively low for the other. It is in fact quite conceivable 
that if all the crew stood up, the centre of gravity might be raised 
as far as M in the case of the sharp-bottomed boat, when an 
accident would be inevitable ; on the contrary, nothing but hoisting 
a weight up the mast could raise the centre of gravity of the flat 
floored boat as far as M. If the centre of gravity of the flat 
floored boat were raised as much as would be sufficient to capsize 
the other, the stability of the boat would only be diminished by 
one third, it would still be twice as great as that of the other boat 
with all her crew sitting down. 
The point M is of great importance in these investigations, so 
much so that it has received a special name, and is called the 
Metacentre. It is defined as the point where the vertical line 
through the centre of buoyancy cuts the original vertical line 
through the centre of gravity. Its position will change with every 
change in the inclination of the boat, but in many common types 
of boat this change is very small, so that within certain limits M 
may be taken as a fixed point. We may say then that stability is 
secured by a high metacentre, or by a broad flat floor which will 
give a high metacentre. We shall see that it may also be secured 
by a heavy weight carried low; but in many vessels and boats 
such a weight would be inconvenient, in which case the broad flat 
floor is the only safe form. Trading steamers are always built 
with a flat floor, and so are life boats ; the figure in fact represents 
very fairly the ordinary midship section of a life boat. On these 
lakes the sharp floor is a very common fault. It should be noted 
and avoided. With a large party, including ladies and children, 
especial care should be taken to choose a flat floored boat, not 
much under five feet broad. Such a boat, if not overloaded, may 
be considered absolutely safe. I may remark, though it has 
nothing to do with stability, that very nervous people, and persons 
with a turn for practical joking, should not be invited to join the 
party, and also that a captain should be chosen before leaving 
shore—a precaution which should never on any account be 
neglected. 
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