SLIPWAY is a shallow ramp that allows freshly-built ships to slide into the water. Initially, slipways were just logs laid in the mud, but later they evolved into concrete, then steel rails. Steel rail slipways often have cradles, to keep the ship uprights as it slides into the water.
Early slipways launched ships length-wise into the water, but during WW2, they started launching ships sideways down shorter slipways.
BAYS are any indentation in the shoreline. The deeper the bay, the less ocean storms toss moored ships about. The best bays are deep, with deep, narrow inlets connecting them to the sea.
PORTS have a huge variety of support services: banks, auction houses, ware houses, customs houses, brokerage houses, whorehouses, embassies, consulates, roads, hotels, bars, dentists, roads, refineries, coal yards, freight-yards, stock-yards, fish-packing plants, fruit-packing plants, railroads and often connect to rivers than allow trans-shipment of goods far inland.
Because they are the center of business transactions, many ports become the wealthiest and most powerful cities in their entire countries, ergo they become the capital cities. A few nation-states (e.g. Togo and Singapore) are little more than support structures for international ports.