Sonata 6 Information, Review, Specs

Sailing Performance & Handling

Under sail, the Sonata 6 is frequently described as having "dinghy-like" agility paired with the forgiveness of a ballasted keelboat. The vessel utilizes a swing keel (centerboard) configuration, which facilitates a draft of just 0.23 meters when retracted, making it ideal for the shallow estuaries and sandy bottom anchorages common in regions like the Gippsland Lakes or Moreton Bay. When the keel is fully deployed to 1.37 meters, the boat exhibits surprisingly good tracking and windward ability.

With a displacement of roughly 650kg and a ballast weight of approximately 180kg, the boat has a relatively high ballast-to-displacement ratio for a trailer sailer. This translates to a stiff feel in light-to-moderate breezes, though like most light-displacement hulls, it can become lively in a blow. According to technical assessments often cited by the Trailer Sailer Association of Australia, the Sonata 6 is capable of competing effectively in club racing under various handicap systems, often holding its own against larger, more modern designs due to its efficient sail plan and clean hull lines. The helm is typically balanced, providing enough feedback to keep a racing sailor engaged without being so twitchy as to intimidate a novice cruiser.

Interior Comfort & Variations

Despite its modest length, the interior of the Sonata 6 is an exercise in functional maritime ergonomics. The cabin layout generally features a "V-berth" forward, which is surprisingly long for a vessel of this size, and two quarter-berths that extend aft under the cockpit seats. This configuration allows for four adults to sleep aboard, though in practice, it is most comfortable for a couple or a small family with children.

The use of a full internal fiberglass liner in many builds—a premium feature at the time—provides a clean, easy-to-maintain finish and helps with structural rigidity. Storage is tucked beneath the berths, and a small, pull-out or fixed galley station is typically located near the companionway. While there is no standing headroom (a common trade-off for its sleek, low-profile cabin trunk), the wide beam of 2.3 meters provides a sense of volume that surpasses many of its 18-foot contemporaries.

In terms of variations, the Sonata 6 was largely standardized, but there are notable differences in the "Mk I" and later versions, primarily involving the cockpit layout and the placement of sail controls. The boat is also a close sibling to the larger Sonata 7 (often marketed as the 6.7), which shares the same Kevin Shepherd design DNA but offers an enclosed head and increased headroom.

Known Issues & Buyer’s Checklist

Prospective buyers should approach a Sonata 6 with a focus on the structural integrity of its mechanical systems and age-related wear common to 40-year-old fiberglass.

• Swing Keel Mechanism: The most critical inspection point is the keel pivot bolt and the lifting cable. In many older units, the pivot bolt can wear the hole in the keel casing, leading to a "thumping" sound while underway. Replacing the stainless steel wire and winch is a standard maintenance task that should be verified.
• Deck Compression: Like many boats of this era with deck-stepped masts, the area beneath the mast step should be checked for sagging or spiderweb cracking. This often indicates the internal compression post or the deck core has softened due to moisture ingress.
• Rudder Integrity: The original wooden rudders or early fiberglass blades are prone to delamination or warping. Modern replacements are often found on well-maintained boats.
• Window Leaks: The plexiglass windows are typically through-bolted or glued; over decades, the sealant tends to fail, leading to moisture damage in the cabin liners and berth cushions.

Community & Resources

The Sonata 6 benefits from a dedicated following in the Australian sailing community. Technical support and original specifications are frequently curated by the Trailer Sailer Association of Australia, which remains the primary authority for class ratings and maintenance advice. While there is no longer a dedicated manufacturer website, various regional sailing clubs maintain archives of the original Sonata Yachts brochures and rigging guides.

The Verdict

Pros:

• Ease of Trailering: Light enough to be towed by a wide range of vehicles and easily launched by two people.
• Shallow Draft: The swing-keel design is perfect for "gunkholing" and beaching.
• Build Quality: Generally well-constructed with a reputation for surviving tough coastal conditions.
• Resale Value: Remains a popular entry-level boat with a steady market for well-maintained examples.

Cons:

• Limited Headroom: The low cabin profile requires a "sitting only" lifestyle while below deck.
• Age-Related Maintenance: Buyers must be prepared to address typical fiberglass aging issues and hardware updates.
• Interior Space: While it sleeps four, it becomes cramped very quickly with more than two adults on multi-day trips.