Knierim Yachtbau: Carbon meets Classic – a high-performance retro classic that floats and sails

The design is reminiscent, in terms of size and appearance, of the BM 31, which the screenwriter and boatbuilder Jan von der Bank built at home in his garage in Eutin, East Holstein (as reported by YACHT Online). However, it is an entirely new design. Gone are the soft chines, which were partly due to the DIY construction method. It is now a consistent round-bilge design. What’s more, according to Knierim’s managing director Steffen Müller, the BM31 classicK – as it is officially known – is set to become even more performance-oriented and refined.

A new construction method: Knierim builds using a cardboard core

The one at Knierim The resulting boat was constructed using an innovative building method. The mould was formed over a core consisting of vertically arranged cardboard discs shaped to the respective frame contour. Paste was applied to this, and the cured paste was milled to the internal dimensions of the future boat. The individual layers of carbon fibre and foam were laminated onto this positive mould; the hull was then filled, sanded and painted.

More about the construction method

High-performance features

The boat is said to weigh just two tonnes; the draught of this fixed-keel yacht, with its stainless-steel fin and T-shaped lead ballast, is a generous 2.40 metres, and the sail area ratio stands at 5.86 – figures typical of pure racing yachts. By way of comparison: cruising yachts have a value of around 4.5. This dimensionless figure represents the ratio of displacement to sail area (upwind), but (contrary to what the name might suggest) has nothing to do with stability.

Carbon fibre hull, rudder and mast

The carbon rig mounted on the keel is made by Pauger and is fitted with spreaders with a 25-degree sweep. Double backstays attach at the masthead and are used solely as a trimming aid. There is an Antal halyard lock, two reefs and a cutter stay for a furling staysail. The rudder (carbon rudder blade and shaft) is mounted in JP3 bearings, and there are four size 40 stainless steel Andersen winches on deck. The bowsprit is extendable to the side, and the headsail furling system is located below deck. ​Down below, there are three berths and a sink with fresh and grey water tanks, as well as storage space in side-mounted pockets. The boat is fitted with either an 8-kilowatt electric drive or, alternatively, a 10 PS Nanni diesel engine.

Technical Specifications

• Hull length 9.50 m
• Waterline length 8.20 m
• Width: 2.75 m
• Draught 2.40 m
• Weight 2.0 t
• Sail area when sailing close-hauled 55.0 m²

In keeping with the theme

• Knierim and the repair of the ‘Holcim’ I.
• Knierim and the repair of the ‘Holcim’ II.
• “Momo II” is the six-cylinder world champion
• Jan von der Bank’s homemade “Rémy”
• Pure 42 review
• Report: Woy 26 Daysailer