area returns a numeric vector of mooring element side-view
area(s), in square metres, taking into account the orientation of
the element with respect to the vertical. (Floats are assumed to be
spherical, so the orientation is irrelevant. This is not the case
for wires and instruments.) The return value will be a single
number if m is a single element but in a typical mooring it will
have multiple values. The areas are listed with the top element
first, i.e. in the reverse order to that used in constructing the
mooring with mooring().
area(m, phi = TRUE)either a mooring object, created by mooring(), or a
mooring-element object, created with anchor(), chain(),
connector(), instrument(), misc(), release(), or wire().
a numeric or logical value that controls how the angle
is computed. If this is FALSE, no angle is used. If it is TRUE,
which is the default, then the value of phi within the mooring
element is used (or 0 is used, if there is no value). Finally, if
phi is a single numerical value, then that is taken as the angle
to the vertical, in radians.
area returns a numeric value of the side-view area, in m^2.
When initially created, objects do not contain an angle value, but
such values are inserted by knockdown(). Moorings that are
significantly tilted will have reduced side-view area, which
will reduce the current-induced drag, as computed with drag().
library(mooring)
# Floats are unaffected by rotation
area(float())
#> [1] 0.7853982
area(float(), pi / 4)
#> [1] 0.7853982
# Other elements, e.g. instruments, are affected by rotation
area(instrument())
#> [1] 0.117
area(instrument(), pi / 4.0) * sqrt(2.0)
#> [1] 0.117