Unstayed Rigs & Cat Ketch Sailboats: A Sailor's Guide to Why They Work

In a Nutshell

Unstayed rigs, whether on a cat ketch or a single-masted catboat, are highly effective, especially for cruising and short-handed sailing. While they may not offer the same upwind performance as a modern stayed sloop, their simplicity, safety, and ease of handling in a variety of conditions make them an excellent choice. The flexible, free-standing masts are self-regulating in gusts, and the distribution of sail area simplifies sail changes, tacking, and jibing, making them an ideal rig for offshore voyaging and casual cruising.

A Nonsuch 30 Catboat at anchor in Falmouth Harbour, Antigua

The Nonsuch 30 from 1976, one of the forerunners of the unstayed mast and wishbone boom concept

What are Catboats & Cat Ketches?
Unstayed Rig Booms: Wishbone vs. Conventiona
Cat Ketch vs. Single-Masted Catboat: Which is Right for You?
What Are the Primary Advantages & Disadvantages of an Unstayed Rig?
Unstayed Rigging & Sails: The Details
Financial & Maintenance Considerations
Deck & Cockpit Layouts
How Do They Perform Compared to Conventional Rigs?
Sailing an Unstayed Rig: Practical Tips & Techniques
Frequently Asked Questions

What are Catboats & Cat Ketches?

Catboats & Cat Ketches are unique types of vessele, instantly recognizable by their tapered masts and the complete absence of standing rigging—no wires, no spreaders, and no tensioned stays to contend with. While this modern rig might seem like a radical invention, the concept of free-standing rigs has been around for thousands of years, with the well-known Chinese Junk being a prime historical example.

The modern iteration of the unstayed rig was championed by designer Gary Hoyt. An accomplished Finn Olympian and World Champion, Hoyt saw the success of these rigs on his racing dinghies and adapted the design for larger cruising boats. This led to the launch of the famous Freedom 40 cat ketch in 1977. This design splits the sail area across two masts, a main and a mizzen, to create two smaller, easily managed sails on wishbone booms.

While the original Freedom 40 was famed for its wishbone booms, the version in the image below points to a common evolution of the design.

A Freedom 40 cat ketch sailing off the wind

In the years after the Freedom 40's introduction, many owners and builders opted to convert the cat ketch rig to use conventional straight booms. This was not a standard option from the factory in the same way the later 40/40 sloop was, but it became a very popular aftermarket retrofit.

The primary motivation for this change was simplicity. The conventional boom, paired with full-length battens and a mast track, offered a more familiar setup that was easier to manage for many sailors. It simplified reefing and sail-hoisting, and it eliminated the need for the special wishbone rig, which could be cumbersome.

The Freedom 40 was originally introduced in the late 1970s as a cat ketch, but the model shown below, the Freedom 40/40 fractional sloop, was a later, standard production model.

$Freedom 40/40 fractional sloop beating to windward$ A Freedom 40/40 fractional sloop

This version, designed by David Pedrick and built in the early 1990s, was a key departure for the company. It combined the simplicity of a free-standing mast with the sailing characteristics of a more conventional sloop. The decision to add a headsail on a forestay was a direct response to a common criticism of cat ketch and single-masted rigs: their reduced performance when sailing to windward.

By including a headsail, the Freedom 40/40 sloop was designed to improve its upwind ability, while still retaining the core benefits of the unstayed mast—less maintenance, reduced complexity, and a safer deck layout.

Another prominent example is the single-masted cat boat, with the Nonsuch 30 (pictured at the top of the page) being a notable representation. This design features a single, large sail set on a wishbone boom, maximizing efficiency without the need for a second mast. Both the Freedom and Nonsuch designs exemplify the unstayed rig's core benefits: simplicity and safety.

The technical brilliance of the unstayed mast lies in its keel-stepped design, which provides the necessary cantilever support from the deck. This flexible structure is subjected to bending moment only, without the compressive forces that a stayed mast must withstand. The mast's ability to bend under pressure acts as a built-in de-powering mechanism, automatically flattening the sail and reducing its power in strong gusts. This innate safety feature is a significant advantage, particularly for inexperienced sailors or when navigating unpredictable weather.

Early designs used aluminium masts, but the introduction of carbon fiber spars was a game-changer. This allowed for even stronger, lighter, and more responsive masts, bringing the design into the modern era of yachting.

Unstayed Rig Booms: Wishbone vs. Conventional

While the wishbone boom has become synonymous with unstayed rigs, particularly on vessels like the Nonsuch 30, a conventional boom is a viable and often preferred alternative for some sailors. The choice between the two fundamentally impacts sail shape and on-deck safety.

The Wishbone Boom: This two-part, V-shaped boom is attached to the mast and extends aft, with the sail's foot secured inside the V. Its primary advantage is its ability to create a near-perfect airfoil shape, almost like a solid wing. The upward force of the wishbone lifts the sail's foot, allowing the flexible mast to bend and the sail to twist more efficiently in gusts, which helps de-power the rig. The design also keeps the boom higher off the deck and presents less of a physical hazard during a jibe.

The Conventional Boom: This is a straight, single spar, just as you would find on a standard sloop. It is a simpler, lighter, and more familiar system. It does not provide the same three-dimensional sail shaping as a wishbone, requiring the use of a vang and outhaul to control sail shape. It can also be a greater hazard in an uncontrolled jibe, as it swings across the cockpit at a lower height. However, some sailors prefer the simplicity and ease of a system they already understand.

The choice is a trade-off between the advanced sail control and safety of a wishbone and the straightforward simplicity and lighter weight of a conventional boom. Both designs are effective, but they serve different priorities for the sailor.

Cat Ketch vs. Single-Masted Catboat: Which is Right for You?

The choice between a cat ketch like the Freedom 40 or a single-masted catboat like the Nonsuch 30 comes down to a few key differences in their sailing characteristics.

Rig Type	Sail Area Distribution	Sailing Characteristics	Best For...
Cat Ketch	Divided between a main and a shorter mizzen mast.	Excellent for managing sail area in changing conditions. The two sails can be balanced to fine-tune the helm. Jibing is incredibly easy.	Long-distance cruising, heavy weather sailing, and when a versatile sail plan is needed.
Single-Masted Catboat	A single, very large mainsail.	Delivers exceptional power and can be very fast, particularly in light airs. The rig's simplicity is unmatched, with only one set of sheets to manage.	Coastal cruising, day sailing, and those who prioritize maximum simplicity and ease of setup.

What Are the Primary Advantages & Disadvantages of an Unstayed Rig?

Based on my decades of experience sailing a variety of rigs, I've outlined the key pros and cons of the unstayed rig. My personal insights, gained from countless hours on the water as an RYA Offshore Yachtmaster, highlight why this rig is so appealing for its simplicity and safety.

Advantages	Disadvantages
Simplicity & Safety: With no standing rigging, there is less to maintain and less to get in the way on deck. Jibing and tacking are effortless—simply change course and the sails switch sides on their own. The flexible masts automatically de-power in strong gusts, reducing the need for constant reefing.	Reduced Upwind Performance: The flexible masts and lack of a conventional forestay mean these boats are less efficient when sailing close-hauled. They tend to point lower than a sloop with a high-tension rig.
Easier to Handle: The sail area is split across two masts (cat ketch) or concentrated in a single large sail (catboat), but in both cases, the individual sails are very manageable for a single-handed or short-handed crew.	Fewer Sail Options: Without the ability to use a conventional jib or genoa, the rig's versatility for downwind sailing can be limited compared to a sloop with a large sail inventory and spinnakers.
Reduced Maintenance: The absence of standing rigging means no need to replace expensive wires, turnbuckles, and other associated hardware, significantly lowering long-term maintenance costs.	Potential for Clutter: While the deck is clear of rigging, the extra mast (on a cat ketch) or the large wishbone boom can take up valuable deck space.
Excellent Downwind Sailing: The ability to sail the two sails wing-on-wing is a significant advantage downwind, providing a stable, powerful ride with minimal risk of accidental gybes.	Aesthetic & Resale Value: The rig's unconventional appearance can be polarizing, which may make these boats harder to resell to sailors who prefer more traditional rigs.

Unstayed Rigging & Sails: The Details

Unstayed rigs are far more than just a mast without stays. The entire system is engineered to work as a single unit, and the sails are a critical part of that.

Because the mast bends under pressure, a conventional, flat-cut sail would lose all its shape and power. Instead, sails for unstayed rigs are designed with a much rounder shape and a looser luff. This allows the sail to work with the mast's curve, maintaining an efficient airfoil shape even as the wind increases. The wishbone boom, often used on these rigs, helps to create a clean, powerful sail shape by stretching the foot and aft sections of the sail. The entire rig is a testament to clever engineering, where the flexibility of the mast is a feature, not a bug.

Financial & Maintenance Considerations

When considering an unstayed rig, a sailor often wonders about the cost. While the initial build cost of a carbon fiber mast can be higher than a conventional mast, this is often offset by significant long-term savings. With no standing rigging to replace every 10-15 years, there is no need for costly haul-outs, rigging surveys, and the purchase of expensive wires, turnbuckles, and other hardware. The long-term maintenance is simplified to the sails, running rigging, and routine mast inspections, which often makes these rigs a more affordable option over the lifetime of the boat.

Deck & Cockpit Layouts

The unstayed rig significantly influences the boat's usability above and below deck. The absence of shrouds and stays creates a completely clear deck, which is a major safety advantage when working on deck or moving around in a seaway. It also allows for greater flexibility in deck hardware placement.

On the other hand, a single keel-stepped mast on a catboat like the Nonsuch takes up a lot of space, which can intrude on the interior layout, particularly in the saloon. A cat ketch with its two masts can also impact cockpit space, although the placement of the masts is carefully considered during the design phase to minimize this. As an experienced sailor, I can tell you that a clear deck is a wonderful thing, and the minor compromises below deck are often worth it.

How Do They Perform Compared to Conventional Rigs?

While an unstayed rig may not be optimized for maximum upwind performance, my experience has shown that its other benefits far outweigh this one drawback for the average cruiser. Unlike a Bermudan sloop, which relies on a rigid mast and highly tensioned stays to achieve maximum lift, an unstayed rig is designed for a more forgiving, stable, and less frantic sailing experience.

When sailing off the wind, the clean, un-rigged airfoils of the sails are unhindered by shrouds and stays, increasing their efficiency. For downwind sailing, the ability to run the sails wing-on-wing on a cat ketch provides exceptional stability, preventing the need for spinnakers or other complex sail handling, which is a major bonus when on a long passage. Single-masted catboats, with their large mainsail, also provide excellent downwind drive.

In light airs, the flexible nature of the rig means a sailor must be more hands-on, adjusting reefing angles and sail shapes to capture every bit of available wind. However, the wishbone booms found on many of these rigs allow for a beautifully shaped sail that's very powerful in marginal conditions.

Sailing an Unstayed Rig: Practical Tips & Techniques

Being well past the first flush of youth, I've had the opportunity to spend a lot of time on boats with a variety of rigs. Here's what I've learned about sailing an unstayed rig effectively:

Tacking & Jibing: The single greatest advantage is the simplicity of tacking and jibing. You simply turn the boat, and the sails flip over on their own. No need to touch sheets or winches.

Sail Balance: The rig is designed to be easily balanced. On a cat ketch, you can fine-tune your course by adjusting the relative sheet tension of the main and mizzen sails. On a single-masted catboat, your primary focus is on the single, powerful mainsheet.

Reefing: Reefing is a straightforward process. You can reef either or both sails on a cat ketch depending on the wind conditions. On a catboat, reefing a single large sail is a key part of the sail plan. In heavy weather, the ability to drop the main and sail under just a reefed mizzen provides excellent control on a ketch.

Handling in Heavy Weather: The automatic de-powering effect of the bending masts is a fantastic safety feature. By simply easing the sheets and letting the sails go forward of the beam, the rig spills wind and stabilizes the boat, making what would be a delicate situation on a conventional boat much more manageable.

That's rather a lot about sailboats with unstayed rigs, but for more conventional rigs you might want to take a look at our recent article The Ultimate Guide to Sailboats & Rigs: Sloops, Ketches & More...

Article written by Dick McClary, RYA Yachtmaster & Yachting Journalists Association (YJA) member.

Frequently Asked Questions

Are unstayed rigs good for single-handed sailing?

Absolutely. The division of sail area on a cat ketch or the single, manageable sail of a catboat, combined with the lack of complex rigging, make them some of the best rigs for a single person to manage, even on larger vessels.

Is a cat ketch the same as a single-masted catboat?

No. A cat ketch has two masts, a main and a mizzen, with two separate sails. A single-masted catboat has only one mast and one large sail. Both, however, share the key characteristic of having unstayed, free-standing masts.

Are unstayed rigs fast?

Unstayed rigs are efficient and capable boats, often sailing at or above their theoretical hull speed. While they may not be as fast as a racing sloop, particularly upwind, their ease of handling and comfort make them ideal for cruising.

What is the risk of dismasting without standing rigging?

This is a common and understandable concern. However, the risk of dismasting is often lower on a properly designed unstayed rig. While a conventional stayed mast relies on a complex web of tensioned wires to stay upright, an unstayed mast is engineered with a stronger, more robust base and material (often carbon fiber) that is designed to bend under extreme loads rather than break. The built-in flexibility is the mast's greatest strength and safety feature.

Do unstayed rigs use a headsail or jib?

Typically, no. The design philosophy of unstayed rigs is centered on simplicity, which often means eliminating the complexity of a headsail and its associated sheets, tracks, and furlers. The large, powerful mainsail(s) on these boats provide all the necessary drive. While some designs may include a small, blade-type jib on a separate, fractionally rigged forestay for upwind performance, it is not a primary component of the rig.

Sources Consulted:

Tanton Yacht Design: The source "Cat-Ketch if you can. - TANTON YACHT DESIGN" provided insight into the design principles and advantages of the cat ketch rig.

B&B Yacht Designs: The article "Why a Cat Ketch?" was used to gather information on sailing tips, especially downwind handling and the self-regulating nature of the rig.

Eric Sponberg: The articles and PDFs from this naval architect's website provided technical details on mast construction, materials, and design.

Boat Design Net & Reddit: These forums were used to gather real-world experiences, opinions, and practical sailing advice from a community of sailors.