2.1 Nos.1 and 2 hatch covers should be effectively
secured, by means of stoppers, against the transverse forces arising
from a pressure of 175 kN/m2.
2.2 No.2 hatch covers should be effectively secured,
by means of stoppers, against the longitudinal forces acting on the
forward end arising from a pressure of 175 kN/m2.
2.3 No.1 hatch cover should be effectively secured,
by means of stoppers, against the longitudinal forces acting on the
forward end arising from a pressure of 230 kN/m2. This
pressure may be reduced to 175 kN/m2 if a forecastle is
fitted.
2.4 The equivalent stress in stoppers and their
supporting structures and calculated in the throat of the stopper
welds is not to exceed the allowable value of 0.8 σY.