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| Development | |
|---|---|
| Designer | Bergström/Ridder/Stillefors |
| Location | Sweden |
| Year | 1993 |
| Design | Sportsboat |
| Name | B&R 23 |
| Boat | |
| Crew | 2-4 |
| Draft | 1.5 m (5 ft) |
| Trapeze | 2 |
| Hull | |
| Type | Monohull |
| Construction | e-glass and polyester resin over divinycell foam |
| Hull weight | 420 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 type | retractable keel |
| Rig | |
| Rig type | B&R |
| Sails | |
| Mainsail area | 22.1 m2 (238 sqft) |
| Jib/genoa area | 10.0 m2 (108 sqft) |
| Spinnaker area | 55.0 m2 (592 sqft) |
History
[edit]B&R 23 was designed in the early 90-ies by Lars Bergström, Sven-Olov Ridder and Torkel Stillefors.
The initial idea came from Stillefors, who had been actively involved in the sail racing circles of New Zealand while living there in the early 80-ies. During his time in New Zealand, Stillefors became very impressed and inspired by the many different high performance extreme dinghies and ultra light displacement sport boats over there. In addition, the 18ft skiffs in Sydney Harbour were also a source of inspiration, and soon Stillefors started contemplate building something similar that could offer similar performance and thrills.
Back in Sweden Stillefors started on his first attempt realizing his vision and by coincidence got in contact with Lars Bergström and Sven-Olof Ridder, at the time a very famous Swedish inventor/design duo, who became interested in Stillefors’ ideas for a new high performance sports boat. This lead them to taking active part in the design of a new boat, the B&R 23.
Bergström designed hull and sail plan at his design office in Sarasota Florida, eventually resulting in a computer printed line drawing, a design technique that was not a very common practice yet in those early days of computer-aided design.
Ridder focused on the design of the hydrodynamic appendices. 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 his residence in Stockholm he designed the 32 degree swept back retractable keel and the rudder.
Stillefors, meanwhile, 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 many sailors on Lake Mälaren would get used to being overtaken by a futuristic looking very fast boat with two deck hands on wire swishing past them with water spraying around the bow.
Design Philosophy
[edit]The B&R 23 is designed with a single guiding principle: it should be fast, very fast!
No considerations were given to any performance limiting handicap or yardstick rules, or other secondary parameters, such as comfort, 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 already in very 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 90-ies and raced in the 1994-1995 BOC Challenge.
The B&R 23 is equipped with the patented ‘B&R rig’.[1][2] The main characteristics of the rig include:
- two rigid struts supporting the lower section of the mast
- no backstays
- 30 degree swept spreaders
- double diamond shrouding
Benefits of the B&R rig are:
- decreased load of mast foot - load spread over three points, allows for smaller mast section, decreasing weight
- increased strength of rig
- the loading of the mast, shrouds and mast foot is decreased
- allows for a large leach in mainsail
The B&R 23 sports a 5 ft rotating bowsprit which allows the asymmetric spinnaker being rotated laterally 30 degrees to windward, to avoid blanketing behind 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, that is comfortably operated with a tackle attached to the mast, combined with the hull shape makes the B&R 23 easy to trailer, launch and retrieve.
Over the years, the original design concept has evolved. 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 easily be retrofitted with these improvements which is proof of the ingenuity of the original design.
Characteristics
[edit]The moment you step onboard the B&R 23, you will notice that you are onboard an ultra light design, with minimal displacement and almost no form stability: walking on the gunwale, the boat immediately heels over. There is not much of weight stability either, the 90 kg’s of the ‘keel’ are far from providing enough momentum to keep the boat upright, even without any wind pressure in the sail plane. In this respect - as well as in many others - 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 onboard. 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, you will rarely if ever sail 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 actively steered for balance by agile crew work and very focused tiller work by the helmsman. It is not possible to ‘force’ the boat doing anything it doesn’t want to, if you try that, you will get instant feedback of less pleasant kind. Instead, as crew, you must learn to cooperate with the boat, to deeply understand how to get it to go where you want it to go. For instance, already in a moderate breeze, under downwind, you must always make sure to have room to bear off - should a gust suddenly hit you, your only option to keep the boat from capsizing is to bear off. This makes overtaking close to windward of another boat quite a thrilling experience.
The very large sail area demands constant active control of the power generated by the sails. As soon as the breeze increases, you must be prepared to spill wind 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[3]. The B&R 23 scores very high, close to the most extreme multihulls.
References
[edit]- ^ The B & R rig, Cruising World video
- ^ Tuning the B&R Rig, SailboatOwners.com article
- ^ Action Index, lifeonthelayline.com
External links
[edit]- Torkel Båtar B&R 23, Manufacturer's specifications
- Another New Approach to Cruising Sailboats, Lars Bergström, B&R Designs
- Torkel Blogg B&R 23 Torkel blogg B&R 23