The Royal Cape One Design
 Sailboat

The Royal Cape One Design has a sail area/displacement ratio of 22.5, which indicates a high-performance boat with plenty of power. It also has a displacement/length ratio of 82.7, which places it in the ultralight category, making it very responsive and agile. The comfort ratio is 16.4, which suggests a lightweight racing boat with a lively motion that may not be very comfortable in rough seas. The capsize screening formula is 1.8, which means that the boat has good stability and righting ability if capsized.

The Royal Cape One Design is not in production anymore. The exact number of boats built is unknown, but it is estimated to be around 20 to 30. The production ended sometime in the late 1960s or early 1970s.

The Royal Cape One Design was originally designed for single-chined plywood construction, but later a fibreglass version was also built from moulds that were made off a plywood boat. The fibreglass version had the same single-chined hull shape as the plywood version, but it was slightly heavier and more durable

The Royal Cape One Design is not designed for cruising or overnight stays, but rather for racing and day sailing. It has a very minimal interior with no cabin or berths, only some storage space and a small cockpit. Therefore, it is not suitable for sleeping on board.

The Royal Cape One Design did not receive much attention from the sailing press, as it was mostly confined to South Africa and never became a popular or widespread class. However, some articles have praised its innovative design and impressive performance, calling it a "miniature ULDB" (ultra light displacement boat) and a "pocket rocket".

Owners of the Royal Cape One Design are generally very enthusiastic and passionate about their boats, as they are rare and unique sailboats that offer a thrilling sailing experience. They enjoy the speed, agility, and responsiveness of the boat, as well as its simplicity and elegance. They also appreciate the challenge and skill required to sail it well.

The builders of the Royal Cape One Design are not well documented, but it is believed that they were mostly amateur or semi-professional boatbuilders who followed the plans provided by van de Stadt. Some of them may have been affiliated with the Royal Cape Yacht Club in Cape Town, where the boat was first launched. The company or companies that built the fibreglass version are also unknown. It is unlikely that any of them are still in business today.

The Royal Cape One Design has a fractional sloop rig, meaning that it has a single mast with a mainsail and a headsail that does not reach all the way to the top of the mast. The sail area is 32.9 m², which is relatively large for its size. The boat can also carry a spinnaker for downwind sailing.

The Royal Cape One Design is a very rare and sought-after sailboat, so it is hard to find one for sale. The price may vary depending on the condition, location, and history of the boat, but it is likely to be in the range of $10,000 to $20,000.

The Royal Cape One Design is a unique and innovative sailboat that does not have many direct competitors in its class. It is much lighter and faster than most other sailboats of its size and age, but also less comfortable and practical. It may be compared to some other ultralight sailboats designed by van de Stadt, such as the Zeeslang, the Waarschip, or the Randmeer.