The evolution of hull and keel forms – Part 1

Classic pilot cutter sailing

Until the 19th century, the art of yacht design had been mainly influenced by tradition, economic and commercial motivations, understanding of materials and their availability, and genuine or semi-scientific developments in hydro and aerodynamics. Boats had been evolved through a long but reliable process of trial and error. But now, rating rules, which most of them had nothing to do with real scientific knowledge, started to play a significant role in hull design on both sides of the Atlantic.

This content is for Pro members only.
Sign up

Related

The evolution of hull and keel forms – Part 2

British "plank-on-edge" suffered from poor form stability. Yet, the deep down located ballast offered a considerable amount of weight stability and positive stability range. These boats rarely capsized, and if so, they didn't remain in that position for a long time. American "skimming dishes" featured higher initial stability. Nevertheless, once the heeling angle exceeded 30 degrees, the yacht was prone to capsize, and if so, it was unable to come back upright. These yachts, although fast in light winds, were unsuitable for cruising.

This content is for Pro members only.
Sign up

Wind triangle

The wind experienced by a fixed observer (true wind) is not the same wind an observer on a moving yacht will feel (apparent wind). The wind triangle helps us understand what the true and apparent winds are and how they are related.

This content is for Subscriber, Advanced, and Pro members only.
Sign up

Frictional resistance of the hull (calculation)

The frictional resistance is a force that is generated when the underwater parts of the boat and the water around are in relative movement (the boat moves through the water, or, in other words, the water passes down the boat). Therefore, it is a hydrodynamic force, and as a resistance, it works in the opposite direction to the movement, trying to slow the boat down.

International Measurement System: Sails

The International Measurement System (IMS) is a set of rules that define what and how is measured on a boat. It is used by the Offshore Racing Congress (ORC) as a measurement platform on its ORC Rating Systems (ORC International and ORC Club). In this article, we deep dive into sails from the IMS perspective.

This content is for Subscriber, Advanced, and Pro members only.
Sign up

Points of sail

The points of sail refer to the course a boat is sailing in relation to the wind. They are defined in reference to the wind angle, which is the angle between the course sailed and the direction of the wind. The following terms are used: close-hauled, close reach, beam reach, broad reach, run, dead-run.

This content is for Subscriber, Advanced, and Pro members only.
Sign up

Frictional resistance of a boat or yacht (calculation)

Calculate the total frictional resistance of a yacht: hull, keel, and rudder. The frictional resistance is a force that is generated when the underwater parts of the boat and the water around are in relative movement. It is a hydrodynamic force, and as a resistance, it works in the opposite direction to the movement, trying to slow the boat down.

Courses

Go to Courses

Merch

Go to Merch

Send us a Message