because water isn't deep enough for them.
Light houses are there to warn shipping of hazardous areas - Rocks, rocky shoreline and sand banks are classedas an invisible hazard. Rocks can ground a ship but are much more likely to hole the hull and sink the vessel.
A lighthouse perched on rocks at sea is typically called a "rock lighthouse" or a "rocky outcrop lighthouse". These lighthouses are built on rocky promontories or cliffs to guide ships away from hazards such as underwater rocks or reefs.
the lighthouse of Alexandria was made to direct ships away from the shore or to the shore
They likely came from ships.
The purpose of a lighthouse is to steer mariners, whilst in dense fog or dark nights, away from cliffs, land and shorelines, coral reefs and other potentially hazardous areas. the lighthouse provides a signal to ships that they are close to such areas. Lighthouses also need to be visible during the day, as they perform the similar function of warning of reefs and underwater hazards such as rocks. The Bell Rock lighthouse off the coast of Scotland, for example, is situated directly on top of a rock which is visible for only a short period of time each day.
I don't think the Romans had a word for "lighthouse" but I suppose the phrases "Turris Lucis" or "Domus Lucis" would suffice. The first means "Tower of Light" and the latter "House of Light."
Because without a guiding light, the ship can't see the shore and it will crash.
easy - keep away from the rocks
Morse code was used in the story "Three Skeleton Key" to send a distress signal by the three lighthouse keepers to warn ships away from the dangerous rocks near the island. The Morse code message helped to convey their desperate situation and seek help from passing vessels.
Because the image and the idea of a lighthouse for a person associates with pure direct connection with nature - sea (ocean) as it is thrilling to see and feel the natural view from the top storey of a lighthouse. It's unique and attractive because it is usually situated on the "dramatic" edge between land and water. It symbolises and incarnates the eternal sight to the sea and the world from up above. It also associates with supernal loneliness of a lighthouse keeper and the lighthouse itself, standing high above the natural relief of earth. It is also appendant to idyllic calmness, harmony, contemplation, melancholy and even nostalgia, as the lighthouse can be realized as a harbinger of the sea on land. People also find the light of a lighthouse showing the way to the ships deeply romantic, and even existential. To sum up, it all about the emersion above down-to-earth life.
To have a better projection and to prevent sailor from getting in to danger of risking their ships, The light is usually found at the top of the structure, therefore its light could be seen from far away.
Lighthouses have always been important for helping ships to navigate away from rocks and reefs that pose dangers to them.
Stay away from the light.