No, these sections are used in propellers where the propellers are required to work efficiently
in either direction. No, not really, we do not want equal efficiency in normal merchant ships
in forward speed condition or an astern speed conditions. Normally, we want some speed in
the astern condition, but we want maximum efficiency in the forward conditions because the
ship will be spending over ninety five percent of its time moving forward. So, the section is
designed to give the forward efficiency high and so, therefore, you use these sections whether
it is tugs, trollers, merchant vessels, naval vessels, whatever.