ams gate . ▁ ▁Royal ▁Har bour ▁Marina ▁ ▁The ▁Royal ▁Har bour ▁has ▁a ▁large ▁mar ina , ▁primarily ▁based ▁in ▁the ▁inner ▁pool ▁of ▁the ▁original ▁har bour , ▁with ▁water ▁levels ▁controlled ▁by ▁lock ▁gates ▁containing ▁ 7 0 0 ▁ber th s , ▁although ▁a ▁number ▁of ▁other ▁ber th s ▁are ▁also ▁available ▁in ▁the ▁outer ▁har bour , ▁and ▁so ▁can ▁be ▁accessed ▁around ▁the ▁clock , ▁rather ▁than ▁just ▁either ▁side ▁of ▁high ▁t ide ▁when ▁the ▁gates ▁open . ▁ ▁The ▁mar ina ▁has ▁a ▁number ▁of ▁facilities ▁for ▁sail ors , ▁including ▁ref u elling , ▁utility ▁hook - ups ▁and ▁amen ity ▁blocks . ▁ ▁The ▁l ighth ouse ▁situated ▁on ▁the ▁West ▁har bour ▁arm ▁was ▁built ▁in ▁ 1 8 4 2 ▁and ▁is ▁ 1 1 m ▁high ; ▁it ▁is ▁a ▁Gra de ▁II ▁listed ▁building . ▁The ▁l ighth ouse ▁is ▁active ▁and ▁em its ▁a ▁continuous ▁red ▁light ; ▁( origin ally ▁the ▁light ▁varied ▁from ▁red ▁to ▁green ▁depending ▁on ▁the ▁height ▁of ▁the ▁t ide ▁at ▁the ▁har bour ▁entrance ). ▁It ▁replaced ▁an ▁earlier ▁l ighth ouse ▁by ▁Benjamin ▁Dean ▁Wy att , ▁which ▁had ▁been ▁poor ly ▁position ed ▁and ▁suffered ▁damage ▁from ▁passing ▁ships . ▁Now ▁power ed ▁by ▁electric ity , ▁originally ▁it ▁was ▁lit ▁by ▁an ▁oil ▁lamp , ▁with ▁a ▁fourth - order ▁F res nel ▁l ens . ▁Car ved ▁in ▁the ▁stone work ▁of ▁the ▁l ighth