Титаник
Chapter 4
Ifsherammedanyobstructionheadon,herbowsmightcrumpleup,butthesteelwallsstretchingacrossherhullandtherewerefifteenofthemwouldpreventthedamagespreadingfarenoughafttosinkher.Ifherbroadsidewasrammedbyanothership,andoneoreventwoofthesecompartmentspierced,eventhentherestwouldbesufficienttoholdherupatleastforadayortwo.Thesebulkheadswereconstructedofheavysheetsteel,andextendedfromtheverybottomoftheshiptoapointwellabovethewater-line.Necessarilytherewereopeningsintheminordertomakepossiblecommunicationbetweenthedifferentpartsoftheship.Theseopeningswerethesizeofanordinarydoorwayandfittedwithheavysteeldoorsnothingeddoors,butpanels,slidingcloselyinwater-tightgroovesoneithersideoftheopening.Therewereseveralwaysofclosingthem;butonceclosedtheyofferedaresistanceassolidasthatofthebulkheads.
Themethodofopeningandclosingthemwasoneofthemanymarvelsofmodernengineering.Theheavysteeldoorswereheldupabovetheopeningsbyaseriesoffrictionclutches.Uponthebridgewereswitchesconnectedwithpowerfulelectro-magnetsatthesideofthebulkheadopenings.Theoperationoftheswitchescausedeachmagnettodrawdownaheavyweightwhichinstantlyreleasedthefrictionclutches,sothatthedoorswouldslidedowninasecondortwointotheirplaces,agongringingatthesametimetowarnanyonewhomightbepassingthroughtogetoutoftheway.Theclutchescouldalsobereleasedbyhand.
