Die Geschichte der B31
The history of the sailboat B-31
The boattype was made by two Swedish brothers named Boström, in the early seventies. They were two wild youngsters and wanted a strong boat, so strong that they could sail into a rock under full speed without any damages to the boat. The idea was not to made an homebuilt boat.
One of the brothers named Bruno Boström made the line-drawing in the end of the 1960 ties to an big boat manufacturer called ASJ/Parca, they introduced it under the name ”Markant”.
It was sailing very bad got a bad reputation and the production stopped quickly.
After that two sailers Tom Sifvert and Bengt Sögerberg changed a lot, they changed the keel from a long to a deep finn-keel, the hull was made longer and the rig taler. Under the name ”Markant 70” the boat won the Skaw Race, and people in Göthenburg area got eyes on the construction and made a club. Two people had the idea to make an purchaseclub to lay down pressure on vendorprices. The club was organised with boathungry sailingfamilies wanting a big boat to a resonable price. The club idea was a great sussex. The report about the boat and club was quickly spred around and a lot more than hundred B-31´s was build each winter in the decade from 1970 in gardens in shipbuilding yards in clubs all around in Sweden.
The construction and lines was made in acc. to all accepted standards for superior boatbuilding and there was added a little more strench to the construction.
The boat meet all Lloyds specifications.
The hull is near and over the keel around 3 cm thick. The keel is made of cast iron with a ”V” shape at top,so it fill the hull over a big area. The bottom of the keel is 45 degrees”v” shape to prevent the water to run to the other side and it give the best hight to the wind.
The keel is fastened to the hull with 5 ea ¾” stainless bolts in the centerline and 23 ea ½” stainless in the periphery Inside the hullfloor timbres, and there is two longgoeing stringers inside on each side of the hull, to make it possible to sail the boat without any accomodation inside.
The mast is strong with masthead rig, and tall for catching the light winds in the archipelago.
Inside plastered in the glassfiber in the stern and bow there is stainless steel plates where the for- and aft-stay is fastened.
The shrouds is mounted in strong angled glassfiber over a length of 60 cm.
Later a swedish boatdesigner named Jens Grandinsson finished the construction.
There is registrated 100 boats, but there is a lot unregistrated up to 3000 in Sweden.
Later people in Denmark became interested and they got an aggrement with a manufacturer making glassfiber swimmingpools and he gave the company the name ”Starboat”.
A plug came from sweden and he started to built hulls for the interested group. Soon a lot of people found out that it was a cheap and a very good boat, and by using own hands they could built a big boat for around 70.000 Dkr. There was no drawings of the accommodation so they built from their head.
Later in 1978 came a new deckplug to Denmark from Sweden. The boat became higher inside and a new bigger cockpit was added.
The type was called B-31 Mark-II.
A danish boatdesigner named Erik Salling made a complete set of drawings to a standard accommodation and the manufacturers son, having a carpentershop, started to produce frames/fronts, galleys- and navsections in teak and magahony.
They foun out that it was a good business to produce kits like deck kit, stearingpedestal kit, accommodation kit ect.
The price was now 120.000 Dkr.
198 ea was built in Denmark, around 85 of those was built and are still under danish flag.
The rest was sold to countries in Europe, mostly Germany and Switzerland. Under the swedish stagnation in the beginning of 1990´s a lot of swedish boats was sold to Denmark. The price varying a lot depending on the quality, from around 90.000 Dkr and up to 250.000 Dkr. For a selfbuilt boat.
Two boats were built on a shipbuilding yard and the price for the latest was 701.00 Dkr.
Within the last two years, before Starboat yard burnt down in 1988, they started to sell an inner shell of glassfiber. They sold only a very few, because the price was around 50.000 Dkr.
A lot of people ask for the boat because it has the right size for a family, its safe and always dry in the cockpit, its strong, it sails like a train, all the same that the turning diam. is only 15-20 meter.
No bad surprice when sailing, you will always feel safe and with good sitting and working comfort in the cockpit in bad weather.
In acc. to the new EU classification rules it is a class ”A”, oceangoing boat.
The speed under engine is normally 6 kn. The engines vary from 10 HP to 55HP.
Under sail the best boat angle is 22 degrees, and the average speed is 6,2 kn.
The calculated max force on the top of the mast at 30 degrees is 1459kpm.
The keel weight is 1706 kg.
The weight of a ”standard” boat is 3200 kg, but normally the weight is around 3500kg.
The boattype was made by two Swedish brothers named Boström, in the early seventies. They were two wild youngsters and wanted a strong boat, so strong that they could sail into a rock under full speed without any damages to the boat. The idea was not to made an homebuilt boat.
One of the brothers named Bruno Boström made the line-drawing in the end of the 1960 ties to an big boat manufacturer called ASJ/Parca, they introduced it under the name ”Markant”.
It was sailing very bad got a bad reputation and the production stopped quickly.
After that two sailers Tom Sifvert and Bengt Sögerberg changed a lot, they changed the keel from a long to a deep finn-keel, the hull was made longer and the rig taler. Under the name ”Markant 70” the boat won the Skaw Race, and people in Göthenburg area got eyes on the construction and made a club. Two people had the idea to make an purchaseclub to lay down pressure on vendorprices. The club was organised with boathungry sailingfamilies wanting a big boat to a resonable price. The club idea was a great sussex. The report about the boat and club was quickly spred around and a lot more than hundred B-31´s was build each winter in the decade from 1970 in gardens in shipbuilding yards in clubs all around in Sweden.
The construction and lines was made in acc. to all accepted standards for superior boatbuilding and there was added a little more strench to the construction.
The boat meet all Lloyds specifications.
The hull is near and over the keel around 3 cm thick. The keel is made of cast iron with a ”V” shape at top,so it fill the hull over a big area. The bottom of the keel is 45 degrees”v” shape to prevent the water to run to the other side and it give the best hight to the wind.
The keel is fastened to the hull with 5 ea ¾” stainless bolts in the centerline and 23 ea ½” stainless in the periphery Inside the hullfloor timbres, and there is two longgoeing stringers inside on each side of the hull, to make it possible to sail the boat without any accomodation inside.
The mast is strong with masthead rig, and tall for catching the light winds in the archipelago.
Inside plastered in the glassfiber in the stern and bow there is stainless steel plates where the for- and aft-stay is fastened.
The shrouds is mounted in strong angled glassfiber over a length of 60 cm.
Later a swedish boatdesigner named Jens Grandinsson finished the construction.
There is registrated 100 boats, but there is a lot unregistrated up to 3000 in Sweden.
Later people in Denmark became interested and they got an aggrement with a manufacturer making glassfiber swimmingpools and he gave the company the name ”Starboat”.
A plug came from sweden and he started to built hulls for the interested group. Soon a lot of people found out that it was a cheap and a very good boat, and by using own hands they could built a big boat for around 70.000 Dkr. There was no drawings of the accommodation so they built from their head.
Later in 1978 came a new deckplug to Denmark from Sweden. The boat became higher inside and a new bigger cockpit was added.
The type was called B-31 Mark-II.
A danish boatdesigner named Erik Salling made a complete set of drawings to a standard accommodation and the manufacturers son, having a carpentershop, started to produce frames/fronts, galleys- and navsections in teak and magahony.
They foun out that it was a good business to produce kits like deck kit, stearingpedestal kit, accommodation kit ect.
The price was now 120.000 Dkr.
198 ea was built in Denmark, around 85 of those was built and are still under danish flag.
The rest was sold to countries in Europe, mostly Germany and Switzerland. Under the swedish stagnation in the beginning of 1990´s a lot of swedish boats was sold to Denmark. The price varying a lot depending on the quality, from around 90.000 Dkr and up to 250.000 Dkr. For a selfbuilt boat.
Two boats were built on a shipbuilding yard and the price for the latest was 701.00 Dkr.
Within the last two years, before Starboat yard burnt down in 1988, they started to sell an inner shell of glassfiber. They sold only a very few, because the price was around 50.000 Dkr.
A lot of people ask for the boat because it has the right size for a family, its safe and always dry in the cockpit, its strong, it sails like a train, all the same that the turning diam. is only 15-20 meter.
No bad surprice when sailing, you will always feel safe and with good sitting and working comfort in the cockpit in bad weather.
In acc. to the new EU classification rules it is a class ”A”, oceangoing boat.
The speed under engine is normally 6 kn. The engines vary from 10 HP to 55HP.
Under sail the best boat angle is 22 degrees, and the average speed is 6,2 kn.
The calculated max force on the top of the mast at 30 degrees is 1459kpm.
The keel weight is 1706 kg.
The weight of a ”standard” boat is 3200 kg, but normally the weight is around 3500kg.