Permeability values to be used for certain cargo spaces (regulation 25-7)
The permeability value for cargo spaces is given in regulation 25-7.
Where a ship is fitted with significant quantities of cargo insulation, the
permeabilities of the relevant cargo spaces and/or the void spaces surrounding such cargo
spaces may be calculated, whilst giving consideration to the volume of insulation material
in those spaces, provided that the insulating material is shown to comply with the
it is impermeable to water under hydrostatic pressure at least corresponding to the
pressure caused by the assumed flooding;
it will not crush or break up due to hydrostatic pressure at least corresponding to
the pressure caused by the assumed flooding;
it will not deteriorate or change its properties over the long term in the
environment anticipated in the space it is installed;
it is highly resistant to the action of hydrocarbons; and
it will be adequately secured so that it will remain in position if subjected to
collision damage and consequent displacement, distortion of its supporting and
retaining structure, repeated rapid ingress and outflow of seawater and the buoyant
forces caused by immersion following flooding.
Stability information supplied to the master (regulation 25-8, paragraph 3)
Linear interpolation should be applied to the GM values only between the deepest
subdivision load line and the partial load line, when developing the curve of minimum
operational Gms or corresponding maximum allowable Kgs.
The need for the provision of position indicators to certain doors which lead to main
cargo spaces (regulation 25-9, paragraph 4)
Those hinged, rolling and sliding watertight doors and ramps which are fitted to
subdivide large cargo spaces, and are not required to be remotely controlled but are to be
secured closed whilst the ship is at sea and are recorded as such in the ship's log, should
not be required to be fitted with a position indicator display at the bridge control position.