Sparkman & Stephens
Swarbrick & Swarbrick
Aquafibre Ltd.
S&S 34 Association (Australia)
# Built
Also Known As
S&S design #1959


Length Overall
33 5 / 10.2 m
Waterline Length
24 2 / 7.4 m
10 0 / 3.1 m
5 8 / 1.8 m
9,200 lb / 4,171 kg
5,400 lb / 2,449 kg
Drawing of S&S 34
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Rig and Sails

Reported Sail Area
452′² / 42 m²
Total Sail Area
453′² / 42 m²
Sail Area
192′² / 17.9 m²
35 0 / 10.7 m
10 11 / 3.4 m
Air Draft
Sail Area
260′² / 24.2 m²
39 11 / 12.2 m
12 11 / 4 m
Forestay Length
42 0 / 12.8 m

Auxilary Power

Fuel Type
Fuel Capacity
10 gal / 38 l


Water Capacity
60 gal / 227 l
Holding Tank Capacity


Hull Speed
7.0 kn
Classic: 6.59 kn

Hull Speed

The theoretical maximum speed that a displacement hull can move efficiently through the water is determined by it's waterline length and displacement. It may be unable to reach this speed if the boat is underpowered or heavily loaded, though it may exceed this speed given enough power. Read more.


Classic hull speed formula:

Hull Speed = 1.34 x √LWL

A more accurate formula devised by Dave Gerr in The Propeller Handbook replaces the Speed/Length ratio constant of 1.34 with a calculation based on the Displacement/Length ratio.

Max Speed/Length ratio = 8.26 ÷ Displacement/Length ratio.311
Hull Speed = Max Speed/Length ratio x √LWL

6.96 knots
Classic formula: 6.59 knots
Sail Area/Displacement
16-20: good performance

Sail Area / Displacement Ratio

A measure of the power of the sails relative to the weight of the boat. The higher the number, the higher the performance, but the harder the boat will be to handle. This ratio is a "non-dimensional" value that facilitates comparisons between boats of different types and sizes. Read more.


SA/D = SA ÷ (D ÷ 64)2/3

  • SA: Sail area in square feet, derived by adding the mainsail area to 100% of the foretriangle area (the lateral area above the deck between the mast and the forestay).
  • D: Displacement in pounds.
<16: under powered
16-20: good performance
>20: high performance
>40: stiffer, more powerful

Ballast / Displacement Ratio

A measure of the stability of a boat's hull that suggests how well a monohull will stand up to its sails. The ballast displacement ratio indicates how much of the weight of a boat is placed for maximum stability against capsizing and is an indicator of stiffness and resistance to capsize.


Ballast / Displacement * 100

<40: less stiff, less powerful
>40: stiffer, more powerful
275-350: heavy

Displacement / Length Ratio

A measure of the weight of the boat relative to it's length at the waterline. The higher a boat’s D/L ratio, the more easily it will carry a load and the more comfortable its motion will be. The lower a boat's ratio is, the less power it takes to drive the boat to its nominal hull speed or beyond. Read more.


D/L = (D ÷ 2240) ÷ (0.01 x LWL)³

  • D: Displacement of the boat in pounds.
  • LWL: Waterline length in feet
<100: ultralight
100-200: light
200-300: moderate
300-400: heavy
>400: very heavy
Comfort Ratio
20-30: coastal cruiser

Comfort Ratio

This ratio assess how quickly and abruptly a boat’s hull reacts to waves in a significant seaway, these being the elements of a boat’s motion most likely to cause seasickness. Read more.


Comfort ratio = D ÷ (.65 x (.7 LWL + .3 LOA) x Beam1.33)

  • D: Displacement of the boat in pounds
  • LWL: Waterline length in feet
  • LOA: Length overall in feet
  • Beam: Width of boat at the widest point in feet
<20: lightweight racing boat
20-30: coastal cruiser
30-40: moderate bluewater cruising boat
40-50: heavy bluewater boat
>50: extremely heavy bluewater boat
Capsize Screening
<2.0: better suited for ocean passages

Capsize Screening Formula

This formula attempts to indicate whether a given boat might be too wide and light to readily right itself after being overturned in extreme conditions. Read more.


CSV = Beam ÷ ³√(D / 64)

  • Beam: Width of boat at the widest point in feet
  • D: Displacement of the boat in pounds
<2: better suited for ocean passages
>2: better suited for coastal cruising



Of all the Sparkman and Stephens production yachts, the S&S 34 has become the most celebrated and perhaps the most successful; no small feat given Sparkman and Stephens’ status as one of the world’s most prestigious and long lived yacht design offices. At the time, designer Olin Stephens (1908-2008) said, “We hope and believe that the S&S 34 will make a good all-round boat, so as to demonstrate in a fairly small package that a good boat for offshore racing will also be a good boat for cruising.”

The words were quite prophetic, the S&S 34 had a successful career as an IOR racer before becoming the boat choice for single-handed record breaking, and eventually earning a great reputation as a blue water cruising boat. The boat has legendary seaworthiness and is a joy to sail being beautifully balanced and easy to single hand.


The S&S 34 was conceived shortly after Olin Stephens designed the 1967 and 1970 Americas Cup victor Intrepid which interestingly was the first 12 Metre to have a separate rudder and keel, an innovation the S&S 34 retained. The design was commissioned in 1968 by a British yachtsman by the name of Michael Winfield. His boat Morningtown was a 36 foot wooden one tonner designed for RORC racing, it impressed him so much he asked Sparkman and Stephens to prepare plans for a production boat. The S&S 34 was the result. The first boat produced was Morning Cloud which went on to win its class in the Sydney Hobart in 1969.

Stephens recounts Winfield, “He set up shop in England, I’m not sure how many he built, a dozen or so, but he was not an experienced boat builder, and he didn’t continue the work. The moulds and tooling were sold to some other builder there, and they built a few more there.”

Thus Winfield & Partners sold one of its two molds to a boatbuilding concern called Aquafibre who continued production until 1974. These hulls were often finished by other boatyards. Some boats found their way to the US where they were sold as the Palmer Johnson 34.

However it was in Australia that the S&S prospered. Downunder, the second set of Winfield molds were owned by Swarbrick Brother Yachts in Western Australia and between the years of 1969 – 1984 the three Swarbrick brothers Tom, Terry and Harley built 34 boats. The company eventually failed under bankruptcy and the molds were then sold to Maybrook Marine of NSW in 1986 who produced a further 4 boats over the following three years. The molds were then stored until 2003 when they found their way back to Western Australia by way of Mike Finn of Cottesloe Yachts, and under consultation with Sparkman and Stephens, boat production was adapted to use the latest in foam sandwich with vacuum infusion technology. These new “Constellation” class boats sold by Cottesloe Yachts were introduced in 2004 and are in current production, built by an all new Swarbrick company called Swarbrick and Swarbrick, owned by Tom Swarbrick’s son Glenn. These new boats are 25% lighter in the hull, are physically stiffer, and exhibit better impact strength.

In total, between 50 – 100 boats were built in the UK and Glenn Swarbricks reports 126 boats coming off the mould in Australia, of which 3 are of the latest “Constellation” class boats built with the latest foam-sandwich GRP technology.

Record Breaker

The boat raced successfully, quickly notching up race victories including future British prime minister Ted Heath’s Morning Cloud winning its class in the Sydney Hobart in 1969, before it became the boat of choice for solo circumnavigation attempts.

In 1981 Jon Sanders set out in his S&S 34 Perie Banou to complete a double-circumnavigation via Cape Horn. Sailing non-stop and solo he set 12 world records including longest distance sailed by any yacht, covering 48,510 miles and longest continuous voyage at sea totaling 419 days.

At age 17, David Dicks set out in 1996, to successfully claim the youngest to circumnavigate solo non-stop via Cape Horn, sailing his Mum’s S&S 34, Seaflight. Jesse Martin bettered the record in Lionheart, completing in 1999 aged 18. Inspired by Martin’s journey, Jessica Watson between 2009-2010 completed her own circumnavigation in Ella’s Pink Lady claiming the youngest solo unassisted at age sixteen (a record that held for only 20 months before Laura Dekker’s sailed home in her Ginn Fizz 37 in January 2012, also at age sixteen).

Boat Configuration

The boat has a remarkably modern shape for a design conceived in 1967. Looking down from above, the hull has a definite diamond shape with a fine bow and a narrow stern. The lines show a short waterline, long overhangs, generous tumblehome and for its era, a relatively high freeboard. Below the waterline is a short fin keel, with nearly all the ballast right in the middle of the boat and a skeg-hung rudder near the very aft. In all a very innovative configuration for its day.

The S&S 34 has a relatively tall masthead rig with a high aspect mainsail and an enlarged foresail, a configuration that became popular in racers in the years to come.

Down below, the headroom in the standard Australian cabin is 6′ 1″ which tapers an inch lower at the main bulkhead. There’s a sea-going berth located on the port aft quarter, with a navigation station slightly forward. To starboard is a the galley. Hanging lockers and a head is forward of the saloon and there is a rather tight V-berth at the forepeak with headroom of 5′ 10″.


MkII versions introduced improved hydrodynamic efficiencies with changes to the keel and rudder. The new keel was deeper with a straighter leading edge and an improved aerofoil section, while the rudder changed to a curved spade rudder hung from a smaller skeg.

Rigs came in two options; a cruising rig, and a racing rig, 2ft taller. In the British boats as well as the early Australian boats had the forestay terminated aft of the bow but on the later Australian boats it was taken right to the end of the bow. There were also variations in the rig during the 1980s, where some boats had a keel-stepped mast and others a deck stepped mast with a much larger cross-section.

The standard engine position is located amidships which provides optimal weight distribution helping seagoing motion, some of the later cruising focused boats, after the advent of lighter engines had the engines located under the cockpit.

The original deck moulds from Winfield had the deck recessed below the sheerline which created a toerail, and the cabin was shaped with a doghouse with a lower forward cabin trunk. When Swarbrick Bros acquired the moulds, they opted to build their own deck mould to improve forward headroom. This has resulted in the Australian boats having a flush cabin trunk, and the sharper observer will notice the deck has been raised flush to being level with the sheerline. Another minor change was a slightly truncated bow to fit the forestay tang.

Under Sail

Over 40 years on, the S&S 34 is still a quick boat. The hull is easily driven and by the numbers only 20hp is required to drive the boat at hull-speed, however owners report less in practice.

When the boat was introduced the S&S 34 was regarded as having exceptional speed to windward and in heavy weather. Even today the boat is hard to beat to windward in more than 10 knots, in fact owners have reported throwing in tacks of 80 degrees.

Her 50% ballast ratio results in a stiff boat, with the first reef thrown in at hefty 25 knots of wind. As the boat heels, the waterline length increases significantly; according to Olin’s design spec, the optimum angle of heel is 23.5 degrees, but don’t expect a dry ride, the S&S 34 is a wet boat like most Sparkman & Stephens designs of that era.

Buyer Notes

There is an active market for the S&S 34 in Australia, no doubt aided by an active owners association. It’s recommended prospective buyers contact them via their online discussion forum when researching. As of 2010, the asking price of boats is in the range of:
1968-1980 $55k-90k AUD

A new Constellation class boat from Cottlesloe Yachts and built by Swarbrick and Swarbrick, depending on fitout, is in the range of $226k-$330k AUD. Hull and deck kits start at $79k.

Links, References and Further Reading

» Sparkman & Stephens 34 Association, discussions, articles, news and more.
» Australian Sailing Magazine, Jul 2005, “37 Years Young” by John Roberson, (a historical look at the S&S34)
» Sail Magazine, A Century of Excellent by Peter Nielsen, (a celebration of the S&S 34)
» Wikipedia, Jesse Martin’s circumnavigation
» Sarwick & Sarwick, company website for the new S&S34 Constellation

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