Page 71 - Introduction to Naval Architecture

58 FLOTATION AND STABILITY

Figure 4.20 Launching

enters the water the waterline at various distances down the ways can be
noted on the profile. From the Bonjean curves the immersed sectional
areas can be read off and the buoyancy and its longitudinal centre
computed. The ship will continue in this fashion until the moment of
weight about the fore poppet equals that of the moment of buoyancy
about the same position.
The data are usually presented as a series of curves, the launching
curves, as in Figure 4.21.
The curves plotted are the weight which will be constant; the
buoyancy which increases as the ship travels down the ways; the
moment of weight about the fore poppet which is also effectively
constant; the moment of buoyancy about the fore poppet; the moment
of weight about the after end of the ways; and the moment of buoyancy
about the after end of the ways.

Figure 4.21 Launching curves