As the name suggests, a bay mouth sandbar can be found at the mouth of a bay and may extend fully or partially across the opening. When it fully extends across the mouth, the sandbar essentially serves to close off that area of the lake or ocean from the rest of the body of water. This can occasionally be dangerous to a passing boat that needs to get through, so in certain areas, groundskeepers will prevent these types of sandbars from forming and obstructing the passageway.
A bay head sandbar is the same as a bay mouth sandbar in composition and appearance, but occurs a short distance from the shore at the head of a bay. Because a bay head sandbar extends into the water from the shore, but is usually attached to the shore on one side, they are often chosen as the perfect location for a restaurant or shop. Customers that frequent a restaurant on a bay head sandbar will get to enjoy views of the ocean on almost all sides and it will almost appear as if they are floating on the water. Appropriately, these types of restaurants are often seafood-themed.
A shoal is an accumulation of sediment in a river channel. It is similar to a bay mouth sandbar in that it can often pose a danger to passing ships because of its central location. They usually occur less than ten meters below the water surface, so a smaller ship will be able to ride right on top of a shoal without being aware of its presence, but a large boat or cruise ship is in danger of getting stuck.
