Designer Jim Voyzey aimed to keep the combined weight of the boat and its trailer under one metric ton. While he technically met this goal, the one-ton limit excludes essential gear such as the outboard motor, fuel, water, and standard boating equipment.

Voyzey drew inspiration from Gary Mull, the acclaimed US designer behind the successful Sonata 6.7 and 8. However, while Mull’s designs are known for being wide, the Sonata 6.3 is notably narrow for a trailer yacht. This slender build reduces the hull’s weight to just 640 kg and boosts its speed, though it does compromise interior cabin space.

The boat sports a distinct appearance, featuring a Mull-inspired stern with a square transom, a high bow with a notable overhang, a moderate sheer, and a hull that transitions from rounded forward sections to a flat aft. Instead of a traditional swing keel, it utilizes a 182 kg ballasted, aerofoil-shaped daggerboard. Controlled by a 10:1 pulley system that runs through the cabin, this daggerboard adjusts the boat’s draft from 150 mm to 1.5 m. Additionally, the rudder is mounted on robust pintles and is buoyant, allowing it to float when released.

Sailing: “Because of its narrow beam, the little 6.3 is tippier at rest than other Sonatas but, the depth of the daggerboard and the low placement of the ballast gives it reasonable stability under sail. Our test conditions were light and the most noticeable thing about the boat was its speed: given the small sail plan and the light breeze, the speed was uncanny. I found no noticeable weather helm but stress again that the conditions were such that its behaviour in heavy air could not be determined. On the basis of similar boats I have tested and the comments of the designer, I think it reasonable to assume the boat would need a deft hand on the mainsheet in a blow, as the ability to depower the rig would be important. Voyzey says when overpressed, the boat skids sideways but does not round up and this makes sense to me on the basis of the feel of the craft in light air…A simple, fast and neat little boat, the Sonata 6.3 impressed with its concept and speed” (Australian Boating, 1983, pp. 60-61).

Specifications

John Crawford Marine 2012, Sonata 6.3, viewed 26 May 2026, https://www.johncrawfordmarine.com.au/advice/trailer-sailer/sonata-6-3

‘Sonata 6.3: Australian Boating Test No. 235’, Australian Boating, July 1983, p. 60. Historical photograph reproduced for identification and historical research purposes. Copyright remains with the original rights holder.

Quick tip: Keep in mind that trailer sailers can vary quite a bit, even within the same class. Take the RL28, for example: they might not all have outboard wells as designed. Some originally may have had inboard engines, and when those were removed, the owners swapped them for a standard outboard mounted on the stern.