The design by Martin Menzner (Berckemeyer Yacht Design) is reminiscent in 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-frame design. Furthermore, 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 boat built at Knierim was constructed using an innovative building method. The mould was created using a core of vertically arranged cardboard discs shaped to the respective frame contour. Paste was applied to this core, and the hardened paste was then milled to the internal dimensions of the future boat. The individual layers of carbon fibre and foam were laminated onto this positive mould, after which the hull was filled, sanded and painted.
More about the construction method
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The boat will be available in various hull and superstructure designs. With a vertical stem and a positive yacht stern – which is also tapered – as well as a moderate beam and low freeboard, the Knierim boat has a timeless appearance and classic features. Designer Martin Menzner sums it up succinctly: “The boat should look good and sail fast.” Menzner classifies the boat as a gentlemen’s daysailer and a retro-classic sports boat.
High-performance features
The former may be a matter of personal taste. As for the second requirement, there are already hard figures: The boat is to weigh just two tonnes; the draught of the fixed-keel yacht, with its stainless-steel fin and T-shaped lead ballast, is generously measured at 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 are attached 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 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 54.5 m²
In keeping with the theme
Fridtjof Gunkel
Deputy Chief Editor YACHT
