EntityQ5634273· pop 5· linked from 15 articlesHMS SealionSign in to save1959 Porpoise-class attack submarineConnectionsPorpoise-class attack submarineEntityInternational Standard Book NumberEntitysubmarineEntityOCLC, Inc.Entitysea lionEntityBirkenheadEntityJolly RogerEntitydraftEntitydisplacementEntityType XXI submarineEntitypennant numberEntitylength overallEntitybeamEntitySpitheadEntitykeel layingEntitylength between perpendicularsEntityOberon-class submarineEntityCammell LairdEntityHMS SeraphEntityfleet reviewEntityCategories1959 shipsBritish Porpoise-class submarinesShips built on the River Mersey