anchor chain equipment marine nautical sea ship iron maritime naval secure security ships wall engineering links machine metal strength strong Taut Tension wheel boat cast isolated journey sail stop gear hoist rope sailing winch windlass ancient black board cast iron cruiser deck heavy military navy steel bow dock dry dock haven holes hull mainstay port prow vessel anchor-chain control gray grey outdoors recreation safe safety sea-going yacht slack yacht yachting chains decay decayed link old rock rocky rust rusty texture wet connect corrode corroded fasten fetter oxidize prison prisoner red rusted slave slavery weight