B&R 23

Last updated
B&R 23
B&R 23 Sportsboat (SWE 9).jpg
+
Development
DesignerBergström/Ridder/Stillefors
Location Sweden
Year1993
Design Sportsboat
NameB&R 23
Crew2-4
Boat
Crew2-4
Draft 1.5 m (5 ft)
Trapeze2
Hull
Type Monohull
ConstructionE-glass and polyester resin over divinycell foam
Hull weight420 kg (926 lbs)
LOA 6.97 m (22 ft 10 in)
LWL 6.67 m (21 ft 11 in)
Beam 2.44 m (8 ft)
Hull appendages
Keel/board typeretractable keel
Rig
Rig typeB&R
Sails
Mainsail area22.1 m2 (238 sqft)
Jib/genoa area10.0 m2 (108 sqft)
Spinnaker area55.0 m2 (592 sqft)

The B&R 23 is a sailing boat designed in the early 1990s. It has an ultralight construction with a very large sail plane. Typical crew is a helmsman and two deck hands in trapezes. The boat is predominately used for racing.

Contents

History

B&R 23 was designed by Lars Bergström, Sven-Olov Ridder and Torkel Stillefors.

The idea came from Stillefors, who had been involved in the sail racing circles of New Zealand while living there in the early 1980s. During his time in New Zealand, Stillefors was inspired by the high performance extreme dinghies and ultra light displacement sport boats there. In addition, the 18ft skiffs in Sydney Harbour were a source of inspiration, and soon Stillefors started contemplate building something similar that could offer similar performance and thrills.

Back in Sweden Stillefors got in contact with Lars Bergström and Sven-Olof Ridder, at the time a famous Swedish inventor/design duo, who became interested in Stillefors’ ideas for a new high performance sportsboat. This led them to taking part in the design of a new boat, the B&R 23.

Bergström designed the hull and sail plan at his design office in Sarasota Florida, resulting in a computer printed line drawing, a design technique that was not common practice in those early days of computer-aided design.

Ridder focused on the design of the hydrodynamic detail. Ridder, working as Professor at the Royal Institute of Technology in Stockholm, had previously built scaled models, very similar to the B&R 23, and performed dynamic tank testing on them to verify the hydrodynamic characteristics of the design. At his residence in Stockholm he designed the 32-degree swept back retractable keel and the rudder.

Stillefors took charge of the superstructure, deck layout and equipment design.

In 1993 the first B&R 23 was built at Bergsviksvarvet in Stockholm by Stillefors, and soon the sailors on Lake Mälaren saw a futuristic fast boat with two deck hands on wire swishing past them with water spraying around the bow.[ citation needed ]

Design philosophy

The B&R 23 is designed with a single guiding principle: it should be very fast.

No considerations were given to any performance limiting handicap or yardstick rules, or other secondary parameters, such as comfort or ease-of-handling. Thus, the philosophy behind B&R 23’s design can be said having been “no-holds-barred”, that is, a ruthless focus on raw performance.

This resulted in an extremely light (420 kg/926 lbs), minimum resistance, high performance apparent wind boat with a huge sail plane, particularly for downwind, where the total sail area is close to 100 m2 (1,000 sqft). The boat is capable of planing in modest winds downwind, and even on upwind the boat performs very well, in parity with much bigger 38–40 foot yachts.

For the hull, Bergström was strongly influenced by Hunter’s Child, an Open 60 ultra light weight design, which was built in the early 1990s and raced in the 1994-1995 BOC Challenge.

The B&R 23 is equipped with the patented B&R rig. [1] The main characteristics of the rig include:

Benefits of the B&R rig are:

The B&R 23 sports a 5 ft rotating bowsprit which allows the asymmetrical spinnakerto be rotated laterally 30 degrees to windward, to avoid blanketing by the jib when sailing deeper angles. It also features a system with two trapezes to maximize the righting moment that the crew can assert on the boat to keep it level. The retractable keel is operated with a tackle attached to the mast.

The most recently built boat is equipped with a deeper and heavier keel (for even better upwind performance) and a carbon fiber mast (to lower center of gravity). The first generation of boats can be retrofitted with these improvements.

Characteristics

The boat has almost no form stability: walking on the gunwale, the boat immediately heels over. There is not much weight stability either, the 90 kg’s of the ‘keel’ does not provide enough momentum to keep the boat upright, even without any wind pressure in the sail plane. In this respect the boat is much more of a dinghy than a keel boat. On water under sail, the boat must be kept upright by active crew work, balancing, hiking, steering and constant adjustment of the power of the sails.

The B&R 23 is very agile, reacting immediately to the tiniest changes in conditions, demanding a high level of alertness and very proactive sailing by the crew, who must be fully synchronised in all their actions on board. Upwind, the boat is able to plane under ideal conditions, however, the best point of sail for a B&R 23 is downwind. Being an apparent wind boat, it will rarely if ever be sailed directly downwind, instead, optimum downwind performance is achieved by gybing downwind while reaching somewhere around 150 degrees TWA, which typically results in AWA’s forward of beam. In most conditions, boat speed will easily exceed wind speed, and in favorable conditions, getting close to factor 2.

As soon as the wind exceeds light breeze, the boat must be steered for balance by agile crew work and tiller work by the helmsman. It is not possible to ‘force’ the boat doing anything it doesn’t want to. In a moderate breeze, under downwind, there must always be room to bear off - should a gust suddenly hit, the only option to keep the boat from capsizing is to bear off. This makes overtaking close to windward of another boat interesting.

The very large sail area demands constant control of the power generated by the sails. As soon as the breeze increases, wind must be spilled to maintain balance. The B&R 23 is kept upright and steered not only by rudder, but by the combination of TWA, balancing, sail trim as well as rudder.

The performance of the boat is exceptional as attested by the Life on the Layline Action Index. [2] The B&R 23 scores very high, close to the most extreme multihulls.

Related Research Articles

Sailing Propulsion of a vehicle by wind power

Sailing employs the wind—acting on sails, wingsails or kites—to propel a craft on the surface of the water, on ice (iceboat) or on land over a chosen course, which is often part of a larger plan of navigation.

Sailboat Boat propelled partly or entirely by sails

A sailboat or sailing boat is a boat propelled partly or entirely by sails and is smaller than a sailing ship. Distinctions in what constitutes a sailing boat and ship vary by region and maritime culture.

Sail plan Diagram of the masts, spars, rigging, and sails of a sailing vessel

A sail plan is a description of the specific ways that a sailing craft is rigged. Also, the term "sail plan" is a graphic depiction of the arrangement of the sails for a given sailing craft.

Jibe Basic sailing maneuver, where ship turns its stern through the wind

A jibe (US) or gybe (Britain) is a sailing maneuver whereby a sailing vessel reaching downwind turns its stern through the wind, which then exerts its force from the opposite side of the vessel. For square-rigged ships, this maneuver is called wearing ship.

Daggerboard

A daggerboard is a retractable centreboard used by various sailing craft. While other types of centreboard may pivot to retract, a daggerboard slides in a casing. The shape of the daggerboard converts the forward motion into a windward lift, countering the leeward push of the sail. The theoretical centre of lateral resistance is on the trailing edge of the daggerboard.

Mainsail Sail rigged to the main mast of a sailing vessel

A mainsail is a sail rigged on the main mast of a sailing vessel.

Tacking is a sailing maneuver by which a sailing vessel, whose desired course is into the wind, 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 opposite maneuver to tacking is called jibing, or wearing on square-rigged ships, that is, turning the stern through the wind. No sailing vessel can move directly upwind, though that may be the desired direction, making this an essential maneuver of a sailing ship. A series of tacking moves, in a zig-zag fashion, is called beating, and allows sailing in the desired direction.

The Ross 930 is a class of fast cruiser-racer yachts named after its designer, New Zealander Murray Ross. The design is marked by light weight and moderate sail area, with a sail-area-to-displacement (SA/D) ratio of about 24, and displacement-to-length (D/L) ratio of 98. The bow section is quite narrow, providing relatively low wave-making resistance and reducing pounding while sailing upwind in waves, and the stern section is wide and flat, making the boat easy to control sailing fast downwind. The interior of the Ross 930 is comfortable, including fitted berths for five, a two-burner stove, galley with sink, and a head. The standard engine is an outboard in a well, but a few boats were built with small inboard diesel engines.

Melges 24

The Melges 24 is a one-design class of sailboat commonly used for racing. The monohull sportsboat is notable for its ability to plane over the water downwind in modest winds, and for its combination of a simple design that is highly tunable.

18ft Skiff

The 18 ft Skiff is considered the fastest class of sailing skiffs. The class has a long history beginning with races on Sydney Harbour, Australia in 1892 and later in New Zealand. The boat has changed significantly since the early days, bringing in new technology as it became available. Because of the need of strength, agility and skill, the class is considered to be the top level of small boat sailing. In Australia this boat is called the "Aussie 18" due to its inherent connections to Australia. It is the fastest conventional non-foiling monohull on the yardstick rating, with a score of 675, coming only third after the Tornado and Inter 20.

Fractional rig

A fractional rig on a sailing vessel consists of a foresail, such as a jib or genoa sail, that does not reach all the way to the top of the mast.

Melges 32

The Melges 32 is a one-design class of sailboat commonly used for racing. The sportsboat is notable for its ability to plane over the water downwind in modest winds, and for its combination of a simple design that is highly tunable.

Olson 30 Sailboat designed by George Olson ca.1978

The Olson 30 is a sailboat designed by George Olson of Santa Cruz, CA around 1978. Olson was a surfer and surfboard shaper who decided to design a 30' ultra light displacement boat while on a delivery from Honolulu to Santa Cruz on Merlin, a 68' Bill Lee designed and built ultralight sailboat which had competed in the biennial Transpac race in 1977. During this delivery, Olson came up with the idea while sailing with Denis Bassano and Don Snyder, who lent their initials to the prototype's name, SOB 30. The resulting boat was christened Pacific High, and it was launched in 1978.

Sportsboat

The term sportsboat first appeared in the late 1980s and early 1990s to describe trailer sailers that were optimised for high performance at the expense of accommodation and ballast. The very definition of the term "sportsboat" is evolving.

The 29erXX is a high performance sailing skiff, it was designed to allow light crews, particularly female crews, to sail twin trapeze boats and as a training boat for the more powerful 49er. The class gained International Sailing Federation Class status in May 2011, but lost it in 2014.

Forces on sails

Forces on sails result from movement of air that interacts with sails and gives them motive power for sailing craft, including sailing ships, sailboats, windsurfers, ice boats, and sail-powered land vehicles. Similar principles in a rotating frame of reference apply to wind mill sails and wind turbine blades, which are also wind-driven. They are differentiated from forces on wings, and propeller blades, the actions of which are not adjusted to the wind. Kites also power certain sailing craft, but do not employ a mast to support the airfoil and are beyond the scope of this article.

Farr 3.7

The Farr 3.7 is a one-person sailing dinghy designed by Bruce Farr in 1971. The design plans are sold by the 3.7 Class Owners Association and they are built by a mix of professionals and home built by amateurs. The 3.7 Class is recognised by Yachting New Zealand as a national class and yachts are sailed in New Zealand, Australia and Great Britain. Full sets of plans have been sold worldwide to a number of individuals with greatest numbers in Germany, Japan, USA, South Korea, Poland, France, Belgium, Russia, Spain, Uruguay.

B&R rig Variant of the Bermuda sailboat rig

The B&R rig is a variant of the Bermuda sailboat rig, designed and patented by Swedish aeronautical engineers Lars Bergström and Sven Ridder. It employs swept spreaders that are usually angled aft, together with "stays" running diagonally downward from the tip of the spreaders to the attachment of the next pair of spreaders to the mast or to the intersection of the mast with the deck that facilitates a pre-bend of the mast that is sometimes tuned into the rig before it is stepped onto the boat. Conventional shrouds thereby contribute to both lateral and longitudinal stability, unlike rigs with unswept spreaders. A B&R rig can be a masthead or fractional rig depending on how stays are configured; a backstay is optional. Such rigs are employed in many of the models of at least one U.S. manufacture and in many thousands of boats, worldwide.

Hobie 17 Sailboat class

The Hobie 17 is an American catamaran that was designed by John Wake as a single-handed racer and first built in 1985.

The ETAP 23iL is a Belgian trailerable sailboat that was designed by Jacques de Ridder as a cruiser and first built in 1994.

References

  1. "The B&R 23". Torkel Boats. Retrieved 13 June 2018.
  2. Action Index, lifeonthelayline.com