66 
shape of the bottom of the boat when broadside on, there 
will be a vertical force resulting from the wind as well as 
the horizontal, and this vertical force will bear down that 
side of the boat toward the wind, and this effect will be 
enhanced by the weight of the waves breaking on this side 
of the boat tending to right her by turning her keel to 
windward, or in direct opposition to the horizontal effect ; 
and, more than this, the vertical • effect of the wind and 
waves to turn the keel to windward will be greatest when 
the windward side of the boat’s bottom has some definite 
inclination to the horizontal, while the horizontal efiect to 
turn the keel to leeward will continually io crease as the 
keel turns to windward, so that it is possible that in a 
particular wind and sea there may be a position of very 
stable equilibrium, towards which, if the keel is to leeward, 
the vertical effect of the wind and the waves predominating 
over the horizontal effect will bring it back, and vice versa ; 
if the keel is turned to windward, the horizontal effect pre- 
dominating will also tend to bring it back. 
The fact that two boats were found stranded bottom 
upwards, with part of their crews underneath, and that one of 
these is known to have upset in comparatively deep water, 
and to have remained in that position during a long time 
while drifting into shallow water, seems altogether incon- 
sistent with the supposition that these upturned boats were 
in their normal condition of instability as when in calm 
weather. For a] though in a calm sea the effect of three or 
four men hanging on to each side of the boat might prevent 
the initial motion of turning, before the weight of the iron 
keel and ballast obtained sufficient leverage to lift the 
weight of the men and so keep the boat stable, this could 
hardly be the case in a rough sea, when the waves would be 
continually altering the balance of the boat. 
These are questions which can only be set at rest by 
experiments, and the method of models thus affords a means 
