Decks above the waterline are usually cambered (i.e . arched) to aid the drainage of any surface water to the gutters, called waterways, which extend fore and aft at the sides of the decks .
Iidekhi ezingaphezulu komgca wamanzi zidla ngokugotywa (lilonke . igophe) ukunceda ukufunxelwa kwamanzi asiwe kwiigathasi, ezibizwa ngokuba ziindlela zamanzi, ezandela ngaphambili nangasemva kumacala edekhi.