Structure of the hull of a ship

The hull is the body of a vessel, without taking into account the rigging (ropes, chains, and tackle used to support and work masts, sails, etc.). The structure of the hull is composed of several different parts that will be discussed next. 

Parts of the Hull

A vessel’s hull is its framework or shell and can be constructed of diverse materials like iron, steel, rubber, wood, aluminum, glass fiber, concrete, polyester and many others.

If we were to stand facing the front of the vessel, the bow would be the front of the ship and the stern the rear, port would be the left side and starboard the right side of the vessel. Now that we have our bearings let’s list and describe the parts that compose the hull of a vessel, and explain their functions.

Bow and Quarters

The bow is the area of the hull that curves into the front, the sides to the front of the vessel are known as port bow and starboard bow.

Same can be said of the quarters, the curved part of the hull located between the beam and the stern of the ship, there is a port quarter and a starboard quarter.

Tack is a nautical term for the side of a sailing craft from which the wind is coming while under way, the starboard or port tack. Also tacking is a sailing maneuver by which a sailing vessel turns its bow toward and through the wind so that the direction from which the wind blows changes from one side of the boat to the other, allowing progress in the desired direction.

The Keel and the bottom of the hull

The bottom of the hull is permanently submerged in the water and bears the maximum load weight. From the keel to the waterline, it is usually painted in red with an antifouling biocide to prevent marine life from attaching.

The volume is contained by the hull and the waterline of the vessel. It corresponds to the submerged volume of the vessel. 


Topsides refers to the part of the hull between the waterline and the deck and remains above sea level. From the waterline to the main deck. There’s where the superstructure is built

It also acts as a buoyancy reserve, which is the volume of a ship above the water plane that can be made watertight for buoyancy purposes.


Separating the hull into two parts, topsides and bottom. It is also the name of a special marking, also known as an international load line, or Plimsoll line, indicating the draft of the ship. It is also called watermark, a line indicating the former level or passage of water.

The waterline may change depending on different factors such as the vessel’s load weight, stowage or the condition of the sea.


Located under the engine room, it’s the part of the hull that would rest on the ground if the vessel were unsupported by water. Bilge pumps are installed to remove the collected dirty water after it’s filtered.

Oily water and other liquid substances drain into the bilge because of rough seas, rain, leaks in the hull or stuffing box, or other interior spillage from the engine room. 

The resulting waste after filtering the waters is called bilge slop and must be stored safely and removed at port for its proper treatment.


The deck is the permanent covering over the hull or over a compartment. Vessels often have more than one, horizontally dividing the area to create floors or decks. They are made out of metal or wood laid over the beams and they strengthen the hull and serve as the primary working surface. 

Decks have different purposes and specific names depending on the structure, form, function or the type of vessel. Some accommodate the passenger cabins, the engine control room, etc. 

Winches, the binnacle, crew seating, or the helm itself are located on different parts of the functional and habitable area of the deck.

que es la cubierta de un barco
Decks have different purposes and specific names depending on the structure, form, function or the type of vessel. Pixabay photo.


The keel is the bottom-most structural member around which the hull of a ship is built. The keel runs along the centerline of the ship, from the bow to the stern. A central beam to which the ribs are attached on each side.

At the prow the keel meets the stem, and the sternpost at the rear. The keel is where all parts of the vessel that make its frame are attached to.


The hull is the watertight body of a vessel, it envelopes its structure and creates the frame. It keeps the vessel afloat and stabilizes it

Hull Shapes

There are many possible shapes for a ship’s hull depending on the purpose for which it’s being built.

The most common hull shapes can be grouped in four categories: flat-bottom (more stability and favors planing), rounded (fishing boats, tugs, trawlers), v-shaped (most popular in recreational vessels) and multihull, like catamarans or trimarans.

In conclusion, the most important parts of the hull of a vessel have been described. Would you like to know more? Get in touch with Suisca Group, and we will gladly offer you all maritime sector related services.