What are the differences between a dinghy and a catamaran when sailing?

All sailboats use the wind in the same way to get around.  There are two main categories of boat to choose from: dinghies and catamarans.

However, a dinghy and a catamaran are two different types of boat in terms of design. They also have their own particularities when it comes to sailing. Here are some key differences.

Hull

A dinghy is a monohull boat, meaning it has a single hull. A catamaran, on the other hand, has two parallel hulls connected by a platform.

Stability

A catamaran is generally much more stable than a dinghy thanks to its beam and the position of the two hulls. It is therefore less likely to capsize than a dinghy. At the same time, its width and weight does make it more difficult to right, and typically requires the use of a rope for righting. A dinghy on the other hand is generally easier to right in the event of capsizing.

Speed and thrills

A catamaran, despite having two hulls, has a smaller wetted surface than a monohull, enabling it to reach higher speeds with the same wind force. In general, a catamaran is faster than a dinghy thanks to its double-hull design, which offers less drag and better lift, and provides a larger sail area (in relation to the boat’s weight). However, this also depends on the size and design of each boat.

Maneuverability

Dinghies are highly maneuverable thanks to their small size, light weight and single hull. They are equipped with a centerboard and pivot directly around it when maneuvering.

Learning

The catamaran is easier at first sight because of its stability, however a dinghy is a good option for fine-tuning skills and could even bring you a step closer to a liveaboard sailboat.

Catamarans are larger, heavier and double-hulled, making them less maneuverable in confined spaces, especially in light winds.

Sailing balance

A monohull heels over when the wind inflates its sails, whereas a multihull or catamaran will “lift”, i.e., one of its hulls, the windward one, will rise out of the water and reduce its contact with it. This will cause the catamaran to accelerate.

In order to accelerate, a monohull that is heeling has to counteract the force of the wind in its sails by redistributing the weight onboard. On small dinghies, this action is known as hiking, or hiking out, and involves stretching the body as far out of the boat as possible, with the feet held firmly under the hiking straps. This action of hiking out is intended to accelerate the righting moment.

Catamaran sailors also use trapezes to counteract the force of the wind with their weight, further accelerating the effect of the restoring torque by being positioned completely outside the surface of the trampoline, attached via the trapeze belt.

Sport dinghies like the RS 700 are also equipped with trapeze.

Capacity

Catamarans are often more spacious than dinghies, offering more room for passengers. Dinghies are generally smaller and designed for one or two people.

Transportability and storage

Catamarans are generally wider than dinghies, as the beams connecting the two hulls are quite long. The dinghy therefore has the advantage of being easier to transport without dismantling the beams, and it’s also easier to store. Both types require a transport trailer. Inflatable models offer an undeniable advantage in terms of transportability. Brands such as Minicat and Grabner offer a range of inflatable catamarans, and Tiwal for inflatable dinghies. These models can be dismantled and packed into bags. Beware, however, of the assembly time for some inflatable catamarans, which can be quite lengthy.

Rigging

Some catamaran and dinghy models are designed as catboat rigs with only one mainsail. Catamarans include the Hobie Wave, while dinghies include the Laser and Sunfish.

Other models are equipped with a jib at the bow, which increases speed and improves upwind sailing. The Hobie Cat 16 catamaran is a classic, as are the 4.20 and 4.70 dinghies.

Last but not least, some models are also equipped with a light front sail (spinnaker) to enhance downwind performance. This is the case with the RS Cat 16 catamaran and the Laser 4000 dinghy.

Some catamaran models like the Erplast XS, or dinghy models like the Tiwal 2, 2L and 3 are boomless, which limits potential head impacts.

Construction materials

The construction materials used in these two categories have a major influence on the boat’s final weight and impact resistance. The RS Sailing range includes two leisure dinghies, the Tera and the Neo, in polyethylene. Polyethylene is very strong but fairly heavy, while fiberglass has the advantage of being light but more fragile. ILCA dinghies and Hobie Cat 16 catamarans, for example, are made from fiberglass. An alternative to conventional hulls is inflatable material, which combines lightness with good shock resistance. Inflatable hulls are less rigid than conventional hard hulls. But in the case of a drop stitch hull inflated at high pressure, like the Tiwal dinghies, rigidity is pretty close to that of a hard hull.