Catamaran Parts Explained: Interactive Guide (For Beginners)


Learning a new skill can sometimes be time-consuming, and learning to sail also means learning a new language with tons and tons of new words that, in the beginning, makes no sense at all.

Some of the words you will read about in this article stem from the early days of sailing. Some are only a decade old; in this article, I have tried to compile all the basic terminology that I believe a beginner needs if he or she wants to understand sailing and catamarans.

Feel free to use this article as a resource and come back to it when you want to look something up or just to learn more!

Main sections on a catamaran

  • Hulls; are what separates a cat from other sailboats, a catamaran has two hulls, a trimaran three, and a regular sailboat, aka monohull, has one. The hull is the part of the sailboat which makes it float and to where all other things are attached. The hulls are usually divided into sections, such as usable and non-usable area. An example of a usable area is the engine room.
  • Cockpit; is from where the boat is maneuvered; it is to here that all halyards, sheets, etc. go. The cockpit contains navigation and steering equipment and is from where the sails, rudder, and engine are controlled.
  • Deck; is the top part(roof) of a catamaran covering the hulls and bridge deck. The deck is made hard enough to walk on. To the deck, attaches lifelines and other equipment.
  • Sugarscoops; are the aftmost part that gets their name from their scoop-shaped appearance; this is where the deck/cockpit meets that water and usually encompasses a stair or ladder for easy access depending on the size of the boat.
  • Cabin; is basically any area on the inside of the boat that is protected from the weather and is made to offer the crew space to rest, eat, and hangout. Inside the cabin, you will find berths (beds), a galley (kitchen), and sometimes specialized areas for repairs or storage.
  • Bridgedeck; connects the two hulls; the inside is the cabin, the top part is the deck, and the entire unit is called the bridge deck. Bridge deck clearance, the bridge deck’s height above the water, is an important factor on a catamaran since a too small clearance will create excess noise and vibrations and fatigue not only the crew but also the boat.

Main areas on a catamaran

Bow (front)

Nothing complicated here; the bow is just a nautical term for the foremost part of your boat. This is where the waves and the sea first meet the hull and depending on the type of boat, the bow(s) can be shaped differently.

Center (Middle)

The part between the bow and the stern is rarely called the center part( middle) of a boat; more common is to speak about the specific area situated within the middle part of the vessel, such as the cabin or the mast.

  • Cockpit; as mentioned above, here you will (usually) find everything that you need to maneuver and navigate the boat, such as a compass, GPS, sheets, steering wheel, and throttles for the engines. Some boats may not be set up this way and require you to move around the boat to access certain controls.

Cabin (inside of the boat)

The boat’s interior is where you will find everything that is made for the crew’s enjoyment; it is a place to eat, sleep, rest up, and hide away from nasty weather.

  • Berths; is a bed; sailors need to sleep too!
  • Galley; is another name for kitchen, usually set up in a very primitive way with a gas stove on a stabilized platform to ensure your food won’t get tossed around.
  • Navstation; or navigation station, is a place, usually with a table, chair, and equipment for planning and logging a journey.

Stern (Back)

Stern is the name for the rearmost part of the boat; there is no clear definition as to where the stern stops and other parts begin, so it is something that the crew will have to figure out on their own through good communication.

Communicating directions on a sailboat

Not only will you have to know the different names of different areas on the boat, but it will also be essential to communicate clearly in what direction something is happening, for example, in a situation where you, the captain, want the crew to observe in a specific direction or pick up a piece of gear somewhere on the boat.

Communication on a sailboat is vital when you want to sail safely and efficiently; here, I have listed the words or phrases used to communicate a direction.

  • Forward; easy as it sounds, it is the same direction as where the bows are pointing. When giving directions towards or beyond the bow, you will use the word “forward” for example; the fender is located forward of the mast.
  • Aft; is the behind the boat. When you are giving directions towards the stern, you will use the word “aft”; for example, the cockpit is located aft of the mast.
  • Port; this will be your left side. Fun fact, in the good old days, you would always dock with the port on your left side; hence port is the left side. If you ever forget which one is which, “port” has 4 letters and so has the word”left”!
  • Starboard; is your right side!

Sails

Types of sails

Sails come in very different shapes and sizes and are a science in itself; in this article, I will focus on the mainsail and three common types of staysail.

  • Mainsail; is, per definition, the sail attached to the mast; its sideways movements are controlled by the boom. When the mainsail is triangular in shape, as on most modern sailboats, it is called a Bermuda rig. Most mainsail uses something called battens.
  • Staysail; mainly comes in two versions, a staysail that does not overlap the mainsail is called a jib. A staysail that is larger and thus overlaps the mainsail is called a genoa.
  • Spinnaker; is a big balloon-like sail that replaces the jib when sailing downwind.

Parts of a sail

  • Luff; the front part of the sail, is connected to the mast through a rail system which makes it possible to hoist or reef.
  • Leech; the back part of the sail.
  • Foot; the bottom part that reaches from the clew to the tack.
  • Clew; back bottom corner.
  • Tack; is the front bottom corner (remember “tacking”?).
  • Head; is the top triangle of the sail and this is where the mainsail halyard attaches.
  • Battens; are pieces of flexible material sewn into the mainsail to increase its aerodynamic shape. Battens can be full length or partial length.

Rigging

Standing rigging

Everything that keeps the sails and mast upright are parts of the standing rigging; it is comprised of wires, cables, and lightweight metal structures.

  • Forestay; usually a metal wire running from the top of the mast to the bow, is sometimes combined with an inner forestay that connects to the mast at a lower point. If the forestay attaches to the top of the mast, the setup is called a masthead rig; if it attaches lower, it is called a fractional rig.
  • Backstay; same as the forestay but attaches to the stern; most catamarans do not employ a backstay system but instead moves the side stays aft.
  • Shroud; much like the forestay but stabilizes the mast sideways and runs from the top to the port or starboard side. Spreaders are used to change the angle of the wire against the mast and better support the mast.
  • Sidestay; connects to the mast below the shrouds and is not pushed outwards with spreaders. On a catamaran, these attach aft of the mast to eliminate the need for a backstay; this makes it possible for a fully battened mainsail with a large roach.
  • Jumpers; are used on a fractional rig with diamond shrouds to add structural integrity to the mast without adding excess weight.
  • Bowsprit; is a pole amidship at the bow that allows for separation of the tacks (foremost, lower part of the sail) for increasing sail efficiency when using two headsails.

Other stabilizing parts

  • Spreaders; act to lessen the angle between the shrouds and the mast; a wider angle will result in forces acting sideways (stabilizing) instead of up and down (bending). This increases stability and decreases the risk of unwanted bending of the mast.

Running rigging

The running rigging on a catamaran is any piece of equipment used to control the shape of the sails, including what is needed to raise them.

  • Sheet; are the ropes (or wire, cables, etc.) that connect to the clew of a sail; on a catamaran, it connects to the staysail (genoa or jib depending on the shape).
  • Mainsheet; is the rope that makes it possible to change the mainsail’s angle; the mainsail can only move in a port to starboard direction(right and left) and not up and down.
  • Staysail sheet; is called after whatever type of sail it is connected to, i.e., jib sheet or genoa sheet. Worth notice is that since the staysail operates on both sides of the catamaran (depending on if your tacking or gybing), it is connected with two ropes, one for the port side and one for the starboard side.
  • Halyards; are the ropes that connect to the top of a sail and make hoisting (or raising) possible. Halyards have different names depending on what sail they are raising, such as Mainsail halyard or jib halyard. Not to be confused with sheets that act upon the sail once they are already hoisted. If the staysail is using a roller furling, then “hosting” is done differently.
  • Furling line; is used together with a roller furling and makes it possible to spool up the sail on the forestay instead of raising and lowering. This makes for a faster and easier way to reduce sail area.
  • Reefing lines; reefing is when you lower parts of your sail to reduce the sail area and reduce the boat’s power and speed; reefing lines are put through holes in the mainsail and attach to the boom.
  • Boom vang; is connected between the boom and deck; it is used to change the mainsail’s shape by pulling downward on the boom. (not very common on Catamarans)

Hulls

In this category, we will look at the hulls and some of the vital parts that attach to them under the waterline.

  • Hulls; differ in their shapes depending on the boat’s purpose, a racing cat would have narrower hulls to reduce drag, and a cruising cat wider hulls to encompass more storage.
  • Rudder; is what changes the direction of the boat. When water passes around the rudders(two on a catamaran), it creates a “pushing force” that makes the boat turn. The rudder is connected to a steering wheel or a tiller at the cockpit through chains and linkage.
  • Centerboard and daggerboards; are sorts of keels that can be raised or lowered to attain certain sailing characteristics. When the keel is up, drag is lower, and so is the draft (how deep the boat sticks in the water). A small draft makes it possible to travel in very shallow waters. The difference between a daggerboard and a centerboard is that a centerboard swivels into place, and a daggerboard is pulled straight up.
  • Mini-keel; is just what it sounds like; it is a keel but very small (a few inches deep) and has no ballast.
  • Crossbeam; is a multihull-only feature and keeps the two hulls from moving in relation to each other. If the crossbeam is damaged or nonexistent, the bridge deck is the only thing that keeps the hulls in place. This will increase wear and sooner or later lead to cracks, or even worse, separation of hull and bridge deck.

Engines

Most catamarans have two engines, one on each hull aft the stern; usually, they are internal with only the propeller in the water. The other option, which is cheaper and most often found on smaller boats, is to have one outboard engine placed amidship (middle).

  • Inboard; engines are situated in a compartment inside the boat at the stern. On an inboard engine, the propeller and the shaft are the only parts outside the hull. Sometimes the prop shaft (propeller shaft) is replaced by a sail drive.
  • Outboard; is a standalone engine usually mounted on the bridge deck amidship(if only one is used) or mounted at the sterns when used in pairs. They are linked together with pushing rods and wires so it can be manipulated from the cockpit.
  • Saildrive; is a type of gearbox that is quieter and vibrates less than a regular propeller and shaft setup.
  • Propeller and shaft; are the most common and cheapest way to propel your boat. It is basically just a watertight axel that sticks out of the hull, and at the end of it, you’ll find the propeller.

Extra gear

There are so many pieces of gear aboard a catamaran that an all-encompassing article would probably fill up the entire internet. Below I have listed the most common equipment that you most likely will encounter on any sailboat.

  • Winches; makes handling lines and ropes much easier. Instead of pulling them with your bare hands, you loop them around your winch and use the handle to crank. Winches come in mechanical style or electrical style.
  • Anchors; is basically just a big hook made to stick to the bottom of the sea. Anchors have different shapes and weights depending not only on the seabed but also on the boat’s weight and size.
  • Navigation; compass, GPS, and maps are all vital pieces of equipment making your trip safe.
  • Cleats; is any equipment that is made to fasten a rope. Cleats come in different configurations; jam, cam, rope clutch, or the most common horn cleat.
  • Block; is a device that can be used in pairs as a pulley (to reduce the force needed to lift something) or on its own to reduce the friction of a rope when the rope can not be drawn in a straight line.

Gabo

Owner of CatamaranFreedom.com. A minimalist that has lived in a caravan in Sweden, 35ft Monohull in the Bahamas, and right now in his self-built Van. He just started the next adventure, to circumnavigate the world on a Catamaran!

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