Do The Unstayed Rigs Of Cat Ketch Sailboats Really Work?
Cat ketch sailboats are instantly recognizable by their tapered masts and total absence of standing rigging. There's nothing new about free-standing rigs though; they've been around for thousands of years - the Chinese Junk being the best known example.
But we have Gary Hoyt to thank for developing these sailboats for modern day cruising boats.
Hoyt, a former Finn Olympian and Sunfish World Champion, recognised that free-standing rigs would be just as successful on cruising sailboats as they were on his racing dinghies, and set out to prove it.
1977 saw the launch of Hoyt's Freedom 40 cat ketch, of which more than 90 have been produced to date.
A Freedom 44 Cat Ketch
Hoyt's early version had aluminium masts, but the development of carbon fibre spars combining strength, stiffness and light weight enabled these sailboat designs to be brought really up to date.
All unstayed masts are keel-stepped as they rely entirely on the cantilever thus provided by the deck for support. The mast is subjected to bending moment only, with none of the compressive forces that a stayed mast has to withstand.
The flexibility of the rig means that it's impossible to get sufficient forestay tension to support a conventional jib, so any such sail is likely to be a blade type set up on a fractionally rigged forestay. More often than not headsails are dispensed with altogether and a single-masted cat rig or ketch rig used - the Freedom 40 being a notable example.
Either conventional booms or wishbone rigs are used to support the clew of the sail. The wishbone rig greatly reduces the risk of head injury from an accidental gybe - a valuable safety feature indeed on cruising sailboats of any kind. Aerodynamically this rig is very clean - few yachtsmen will lament the loss of the rigging-induced whining when it starts to blow, but it does mean there's less to grab hold of when up on deck.
Advantages of Unstayed Rigs on Cat Ketch Sailboats
- Absence of shrouds and stays means less weight aloft;
- Low centre of effort produces less heeling moment than a conventional rig;
- Flexible unstayed mast bends in strong gusts, flattening sail and de-powering it;
- Ease of tacking and jibing - just change course and the sail will flop over onto the other side of the boat without any drama;
- Running downwind is similarly stress free, with one sail out to port and the other to starboard. If the wind pipes up both sails can be eased forward, spilling the wind and steadying the boat.
It's often said that they're less efficient to windward than the Marconi Rig (the Bermudan Sloop), but off the wind they make up for it.
However, if you take a look at this this video of a heavily reefed 40 ft cat ketch sailboat overhauling a 48 foot cutter you'll have few doubts about their windward ability!
Cat ketches clearly have a lot going for them!
Seen alongside the complexity of a conventionally rigged sailboat, it's easy to imagine that the unstayed rigs of cat ketch sailboats represent the future for cruising sailboat designs
The Cat Ketch Sailboat: A Few FAQs...
A cat ketch sailboat is a sailboat that has two masts, one at the very bow and one further aft, and no jib. The sails are usually triangular and attached to free-standing masts that can bend and de-power in strong winds.
Sailing a cat ketch sailboat is similar to sailing any other sailboat, but with some differences. Here are some basic tips:
- To tack, simply turn the boat through the wind and let the sails switch sides. You don't need to touch the sheets or the tiller during the manoeuvre;
- To jibe, turn the boat away from the wind and let the sails switch sides. Be careful not to jibe too fast or too hard, as this can damage the masts or cause excessive rolling;
- To reef, lower the halyard until the desired amount of sail is left, then secure it with a cleat or a knot. You can reef either or both sails depending on the wind strength and direction;
- To trim, adjust the sheets until the sails are set at an angle that gives you maximum speed and comfort. You can also use the wishbone booms to change the angle of attack of the sails.
Some examples of cat ketch sailboats are:
- The Freedom 40, designed by Gary Hoyt in 1977, was one of the first modern cat ketch sailboats. It has an aluminium mast forward and a carbon fibre mast aft, and can carry a small jib on a fractional forestay;
- The Herreshoff 31, designed by Halsey Herreshoff in 1979, is a classic cat ketch sailboat. It has wooden masts and wishbone booms, and can carry a spinnaker for downwind sailing;
- The Core Sound 15, designed by Graham Byrnes in 2015, is a small cat ketch sailboat. It has carbon fiber masts and conventional booms, and is suitable for beach sailing and day cruising.
The above answers were drafted by sailboat-cruising.com using GPT-4 (OpenAI’s large-scale language-generation model) as a research assistant to develop source material; to the best of our knowledge, we believe them to be accurate.
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