Skärgårdskryssare also known as Square metre boats, are these slim and flat-hulled boats to enjoy sensational sailing. Sadly, the time aboard ends in the evening, as a classy skerry cruiser offers hardly any comfort. That’s why there is a compromise, the so-called cruising sqm boat. A remarkable variant is the Jubilee S40.

How the Jubilee S40 sqm boat comes about

December 1980 naval architect Knud Reimers develops a 40 sqm Skärgårdskryssare on behalf Stockholm sailors Christoffer Hillbom and S. Irving. As a closer look at the drawing reveals, Reimers calculates a pretty optimistic displacement of just 4.25 t with a design waterline of 10.45 m. The length measurement of the so-called ideal length, called “Li”, taken 21 cm above that design water line at the 40 sqm class is supposed to be 11.72 m. Here you find a closer look at the Li measurement.

The true Skärgårdskryssare is a fairly empty race boat with spartan equipment. It has no engine, tanks, pantry, refigerator, batteries, no furnished cabins by todays standards and no aft cabin. Auxiliary propulsion with the initially planned 7.5 hp Volvo Penta MD5A single-cylinder add around 550 lbs (250 kgs) to the Jubilee S40 including gearbox, 70 l tank and starter battery.

So there is a difference between the design waterline and the actual waterline of the initially launched boat. And then comes a third waterline including later installations and modifications, like a stronger engine, larger batteries and additional holding tanks for Lake Constance permission. All this adds up to the actual weight.

Boat data Jubilee S40 first draft

Length over all	14.25 m
Design water line	10.45 m
Li (relevant ideal lenght) measured 21 cm above DWL at 40 sqm boat	11.72 m
Beam	2.65 m
Draft	1.85 m
Weight	4.25 t
Ballast	2.2 t

Jubilee S40 as square metre boat

The sail plan from December 1980 announces a boat with 40 square meters of nominal sail area, consisting of 27.6 sqm mainsail and 12.4 sqm (80 percent headsail area. In this article you find a closer look how nominal sail area is calculated at sqm boats. As the design becomes heavier than planned sails are soon getting bigger, as drawings of the Jubilee S40 with 55 and 65 square meters indicate. So the 40 simply reminds us of Reimers’ first idea.

In view of the experience with previous cruising sqm boats S30 and Swede 55, which turned out to be way heavier than planned, it remains unclear today how the weight and thus the waterline should be maintained in this design. The displacement of the Jubilee S40 is soon adjusted from 4 1/4 to 5.3 t. In fact, the Finnish Celeste and the Lake Constance boat Traumfänger weigh around 6 tons. The article about the 75 square metre boat Gustaf describes the challenge to achieve a rule-compliant sqm boat.

50th anniversary as naval architect

Reimers came from Bremen in August 1930 as a newly qualified naval architect from Abeking & Rasmussen to Stockholm, where he worked for Gustaf A. Estlander. After his boss’s sudden death December 1st , 1930, he took over Estlanders office the following year. Being self-employed since 1931, Reimers is celebrating his 50th anniversary with the design. And he is 75 years old when Tufa Marin in Färetuna on Lake Mälaren west of Stockholm presents the project with this magenta coloured poster. Soon it is introduced as Jubilee S40 and the prototype launched 1983.

It is interesting to note the similarity to Swede 55, which Reimers designed in 1974–75 with the sail geometry with the fractional rigged spar typical of a sqm boat, where the headstay sits well below the masthead. The spoon bow, the flat-boarded, elegant hull with subtly curved sheerline, the stretched cabin superstructure raised with a step at the aft. Further the center cockpit and aft cabin suggest a Swede 55 at first glance. A second look at dimensions such as length and width shows that the Jubilee S40 is a 90 percent Swede 55.

And the construction is similar to the 40 sqm One Design, as Reimers designed in 1974 when developing Swede 55. The essential steps to Swede 55 are documented in this page. From a displacement perspective as well, the boat fills the gap between the 12.50 m long S30 and the 16 m Swede 55. The S30 was planned for 3.6 t, Reimers considered 7.75 t for Swede 55. The Jubilee S40 is soon seen at 5.3 tonnes. In fact, an S30 weighs around 4 tons, the Jubilee S40 weighs up to 6 tons and Swede 55 up to 9 tons.

Gap between S30 and Swede 55

With 304 units built, the S30 was a success, as was the Swede 55 with 27 Fisksätra yard manufactures, the latter continued being built by a successing yard in the 1980s. So it makes sense at the beginning of the 1980s to close the gap with this model.

Reimers is a passionate sailor who enjoys his own S30 well into his old age. He lives his time out on the water to the fullest and, to the chagrin of his wife Effi, his sons and other fellow sailors, sometimes forgets to return to land on time. Sailing in the Stockholm archipelago means so much to him that he encourages the foundation of a museum on the island of Stora Fjäderholmarn to document maritime life in the Skärgård. The logo of the Jubilee S40, which shows a crowned wild goose, reminds on his enthusiasm for sailing in one of the most beautiful waters of our world.

In the fall of 1995 I had the opportunity to sail the first example of the Jubilee S40 called Astragal, shown above, in the Stockholm archipelago. The owner was so kind to let me spend the night on board and I got an idea of life aboard.

The lightly smaller proportions compared to Swede 55 are also noticeable when it comes to the height below deck. The Jubilee S40 offers close to full headroom. The elegant appearance and limited freeboard height comes at a price. It’s a price that boat buyers at 14.40 m (47 feet) were hesitant to pay back in the eigthies and hardly pay today.

The traditional cabin interior in varnished mahogany with red velvet upholstery makes the boat appear dark and narrower than it is. However the Jubilee S40 was also built different. The S30 is 2.50 m wide, the Jubilee S40 is 2.70 m, Swede 55 has a beam of three meters.

The story of the Jubilee S40 Meteor

The Bavarian aeronautical engineer Werner Dusold spent a while with the smaller sister S30 before hoisting sails aboard his Jubilee S40. And as you can see he hoisted a lot.

Advised by Knud Reimers and the spar builder Seldén, he rigged boat number 8 significantly larger and set off with enormous sail area. The photo shows that Meteor, like a Libera racer, is optimized for light thermal breezes on the lakes near the Alps. Aluminum brackets folded sideways help to make best use of the crew weight in the trapeze. Dusold reports top speeds between 14 and 18 knots in suitable conditions on Lake Chiemsee. The top spinnaker has 262 sqm. Dusold was friends with Knud Reimers and, like Reimers, is a steadfast advocate of the traditional keel-rudder configuration, where the rudder hangs from the keel fin.

It’s hard to believe that Dusold sails this boat with his family on the Mediterranean and Atlantic. In 1987 he takes part in the Fastnet Race, where, according to his descriptions, he left much larger boats behind in the brutal upwind beat from the Solent to Lizard Point.

Boat data Jubilee S40 Meteor

P (Mainsail Luff)	18.78 m
E (Mainsail Base)	5.40 m
I (Hight headsail ∆)	20.30 m
J (Base headsail ∆)	4.75 m
Mainsail	59 m2
Jib	30 m2
Genoa 1	59 m2
Up Wind Sail Area (Main & Jib)	89 m2
Displacement due to measurement certificate	5.7 t
Segeltragzahl Groß & Fock (bezogen auf 5,7 t)	5.27
Segeltragzahl Groß & Genua (bezogen auf 5,7 t)	6.07
Light air top spinnaker	262 m2
Engine 10 HP Outboard

Sail dimensions according to DSV measurement certificate 80329 from July 13, 1987. The “Segeltragzahl” is a dimensionless number based on the following calculation: (2√sail area in m2 / 3√displacement in t). The higher the value, the more sail area the boat has in relation to its displacement. Cruising yachts ≈ 3.5 – 4, modern boats ≈ 4.3 – 5.

As an engineer and sailor, Dusold is familiar with weight issues. That is why he used a light outboard motor instead of a heavy inboard engine. An example of what these boats do to serious sailors.

However sailing can be enjoyed less spectacular with a standard boat. The fleet of Jubilee S40s, which are predominantly based in Sweden and Finland, proves this. As the photos and the following overview show, there is also a fine example on Lake Constance.

Which Jubilee S40 are sailing where

Nine or ten boats were probably built in the 1980s. Beck & Söhne completed some hulls and decks obtained in Sweden for German owners. This table documents the fleet similar to the S30, its second version and Swede 55. There are still gaps to be filled. The information comes from various, partly old sources. Identified sail numbers are marked bold. If you know more, please send a message. As of December 3, 2023

Launched Sailnumber	hull colour	Name	Located	Remarks
1983 S 1	white	Astragal	Stockholm Archipelago	blue coveline
1983 S 2	white		Stockholm Archipelago	red coveline
1985	white	Celeste	Espoo/Finnland	blue deck, teak interiour, separate rudder, 24 HP engine
198? S 6	white	Emilie		blue coveline
1984 G 7	white	Siegfried, Traumfänger	lower part of Lake Constance, Insel Reichenau	Completed by Beck & Söhne, rudder attached to keel, second owner since 2003, teak deck, wheel steered, shear-guard, extra spreader for top spinnaker, 6 t
1984 G 8	white	Meteor	Chiemsee, Atlantic, eastern Mediterranean, Lake Constance, Schlei, Baltic sea/Northern Germany	long spar, many races and cruises, second owner since 2022
1987 G 10	white	Aphaia	Lower part of Lake Constance, Reichenau Island, Baltic Sea	Completed by Beck & Söhne, separate Rudder, mahogany interiour, teak deck, separate helmsman cockpit, many extras, 19,35 m spar, 50 sqm main, 27 HP Engine
1990 SWE 10	white	Ellen	Stockholm archipelago	separate rudder mahogany plated counter, 20 m spar, ≈ 6 t

Boat data Jubilee S40 standard version

Length over all	14.40 m
Waterline	10.70 m
Beam	2.70 m
Draft	2 m
Displacement	≈ 5.3 – 5.5 t
Actual displacement Celeste & Traumfänger	≈ 6 t
Ballast (Lead)	2.55 t
Up Wind sail area (Main & Jib)	65 m2
Mainsail	40 m2
Jib	25 m2
Genoa 1	40 m2
Genoa 2	32 m2
Spinnaker	97 m2
Segeltragzahl Groß & Genua (bezogen auf 5,3 t)	4.5
Recommende Engine: Volvo Penta 15 HP (11,2 kW) with shaft or Saildrive
Cabinheight companionway	≈ 1.72 m
Cabinheight saloon	≈ 1.68 m

Two berths in the forecabin and two in the aft cabin. Two bunks in the saloon. Tanks for 70 l fresh water and 70 l diesel. The boat is sailing with different keel/rudder configurations and spar lengths.

Thanks to Werner Dusold, Tanja and Thomas Jäger, Lars-Olof Norlin (1932-2017), S. Irving, the Sjöhistoriska Museet/Stockholm, Ulf Torberger. Photo at the top by Tanja Jäger: Jubilee S40 Traumfänger on Lake Constance.

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