In many ships, particularly merchant ships, the ship's side abreast the waist and well-decks is built up several feet above the upper deck by a strake of plating joined to the gunwale and known as the bulwarks; these form a protecting breakwater against heavy seas, and prevent the crew from being washed overboard or falling overboard, and they are pierced at intervals with openings fitted with hinged flaps called freeing ports, to allow the escape of any water shipped in a sea-way .
Kwiinqanawa ezininzi, ingakumbi iinqanawa zorhwebo, amacala azo aphakamile kwaye anedekhi ezomeleleyo nezakhiwe ngasentla kumgama ongangeenyawo eziliqela ngaphezulu kwedekhi engasentla ngomchwe wesigqumo esidityaniswe kumphetho wenqanawa owaziwa ngokuba ludonga lokhuselo; ezi zenza isikhuseli samanzi ezichasene neelwandle ezilwayo, kwaye zikhuselel nabakhweli ekubeni bakhukuliseke bakhutshelwe ngaphandle ngamanzi, kwaye agqojoziwe kwiziphumlisi ezinemingxuma efakelwe amablayi anehenjisi abizwa ngokuba zindawo zokukhululeka, ukwenzela ukukhutshelwa ngaphandle kwamanzi athe angena ngaphakathi enqanaweni.