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 √LWLA 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
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
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
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
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)
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)
The Hallberg-Rassy 31, designed by German Frers and introduced in 1992, has been one of Hallberg-Rassy’s most popular models for many years. The yacht strikes a harmonious balance between comfort, safety and performance as a go-anywhere cruiser on the smaller end of the offshore sailing spectrum.
The yacht enjoyed positive reviews in the press upon her introduction and through the years earned praise from hers owners. Bob Perry, one of the great names in cruising design, wrote in Sailing Magazine, “Frers has given us a nice boat. I like just about everything about this design, from its high cockpit seatbacks to the fractional rig.” While closer to home, Swedish yachting magazine Båtnytt wrote, “Extremely spacious, light and inviting interior. The sailing and sea-going qualities are in a class of its own.”
Hallberg-Rassy’s change to Frers as designer has given this 31 footer a much needed boost of speed over her predecessors, for a cruiser her speed through water and close windedness is excellent in most sea conditions. However she’s known to struggle in light winds and also short choppy seas. The boat is well balanced is easy to single hand with all her control lines lead aft to the cockpit.
Under heavy conditions the boat is sea-kindly and has safe docile characteristics, as one owner put commented, “it always feels nice arriving in carpet slippers and smoking jacket rather than a drenched oily.”
The design pairs a beamy medium displacement hull with an efficient fin keel and a balanced spade rudder. Her sweeping sheerline belies a low freeboard, which helps keeps her windage low, while interior headroom is achieved by a higher cabin-top. The low freeboard arrangement also manages to keep the crew dry and well protected by use of a high cockpit wall and Hallberg-Rassy’s trademark fixed-windscreen.
The rig also continues the theme of cruising practicalities and performance. Frers has opted for a fractional rig, a configuration more often seen in racers, but is devoid of the extra hassles of running backstays to support the head of the genoa, instead relying on its masthead backstay and an aft-swept spreader to provide forestay tension control.
Belowdecks is a layout that feels light and spacious with mahogany joinery that has become a Hallberg-Rassy trademark. There are two spacious double cabins, one forward and one aft, and a large head and shower compartment aft. The saloon is of a good size and there is ample space in the galley and the chart tables is full sized. Going against the “full-sized” theme, owners comment that the berths are quite small, best suited to those under 5′ 10″ in height. The cockpit is comfortable, well protected and can accommodate a decent crew without issues. Part of the starboard seat lifts up to give access to a very generous stowage area.
All put together the Hallberg-Rassy 31 is a solid cruising yacht featuring the popular qualities of larger Hallberg-Rassys in a small package. She can cope safely in all weather conditions, practical for cruising life, and easy to sail. With an extremely long production run from 1993 to 2009, prices can vary dramatically depending on age and wear and tear.
The Hallberg-Rassy 31 continues from a very popular line of 31-footers. The Swedish yacht maker Hallberg-Rassy has alway distinguished itself for building quality yachts on the high end of the market, many noting it as the Mercedes Benz of boatbuilders.
Not long after 1972 when Harry Hallberg and Christoph Rassy merged their boatyard operations to become Hallberg-Rassy, the company’s Olle Enderlein designed Monsun 31 quickly became the company’s most popular model, in fact it sold 904 boats between 1974-1982 making it the all-time best seller. This model was complemented and eventually superseded by the 312, a more modern design by Christoph Rassy and Olle Enderlein which saw the introduction of a fin keel. The 312 was also very popular with 690 boats built between the years 1979-1993.
The Hallberg-Rassy 31 was introduced in 1992 to replace the long running 312, keeping many of her traits but with a lighter beamier hull and refinements throughout. This time the design was by German Frers who has been the exclusive designer for Hallberg-Rassy since 1989, his designs have added much needed performance to the Hallberg-Rassy lineup.
By 2006, the design was updated with a MkII version, the changes were minor, the most significant is a rig change to a lighter twin-spreader mast and an engine update, there were also many improvements to the interior furnishings. Like her forebears Hallberg-Rassy 31 enjoyed a long production run, lasting 18 years and 356 boats, before being replaced by the Hallberg-Rassy 310 in last 2009 – a slightly smaller and lighter sailboat.
Great choice! Your favorites are temporarily saved for this session. Sign in to save them permanently, access them on any device, and receive relevant alerts.