On a flush deck ship with a substantial deckhouse amidships
the deckhouse is considered to provide sufficient break to form two
wells and each could be given the required freeing port area based
upon the length of the "well". It would not then be necessary to base
the area upon 0.7L.
In defining a substantial deckhouse the breadth of the deckhouse
should be at least 80% of the beam of the vessel, and the passageways
along the side of the ship should not exceed 1.5 metres in width.
Where a screen bulkhead is fitted completely across the
vessel, at the forward end of a midship deckhouse, this would effectively
divide the exposed deck into wells and no limitation on the breadth
of the deckhouse is considered necessary in this case.
Wells on raised quarter decks should be treated as previously,
i.e. as being on freeboard decks.
With zero or little sheer on the exposed freeboard deck
or an exposed superstructure deck the freeing port area should be
spread along the length of the well.