File:TRANSVERSE SECTION AT THE ENGINE-ROOM OF H.E.I. COMPANY'S IRON STEAM VESSEL PHLEGETHON.jpg

English: Showing the method of giving additional strength by originally building-in the coal-box bulkheads as part of the vessel.

   A Keel.
   B Floorings.
   C Keelsons.
   D Deck beams (iron).
   E Deck.
   F Covering-board, 18ft. by 4in.
   G Longitudinal iron bulkheads, built into the vessel, forming the sides of the coal-boxes.
   H Angle-iron stay-beam between.
   I Side frame and coal-box bulkhead.

N.B.—These bulkheads appear to have remedied the weakness complained of in the Nemesis, as the Phlegethon is reported, after nearly three years' hard service (including the passage round the Cape, when she experienced very bad weather), in as good order as when she left England, never having required any alteration or strengthening.