Design Brief & Intent
Thorne designed the Timpenny 670 to be managed easily by a "husband and wife" crew, prioritizing light sheet loads, straightforward fractional rigging, and manageable deck gear. In a market saturated with heavy-displacement pocket cruisers, the 670 carved out a niche by offering genuine speed without requiring complex physical effort to sail. The interior finish demonstrates a clever approach to space planning. Rather than treating the centerboard trunk as an inconvenient barrier, Thorne integrated it as the structural support for the saloon table, allowing four adults to sit comfortably without knocking elbows. The layout features a surprisingly spacious double V-berth forward, separated by a privacy bulkhead with space for a chemical marine toilet underneath. A full-length starboard settee and quarter berths complete the accommodations, sleeping up to four adults. The compact galley is situated on the port side, neatly positioned against the forward bulkhead.
Variations & Configurations
While the fundamental hull shape remained consistent over its production run, owners will find a few distinct configurations on the used market. The standard version features a heavy, retractable drop-keel (often categorized as a wing keel in modern databases) that houses 485 pounds of ballast in a daggerboard-style plate. However, some hulls were built or later modified with a swing-keel configuration. This swing-keel variant was highly favored by owners cruising shallow, tidal regions where the ability to safely ground out on the sand was a priority. Additionally, many models feature a fiberglass "pop-top" companionway hatch. This highly desirable option significantly increases headroom when anchored, transforming the low-profile cabin into a comfortable space with standing room for food preparation and moving about.
Sailing Performance & Handling
Under sail, the Timpenny 670 behaves more like a light-displacement racing keelboat than a typical caravan-style trailer sailer. An exceptionally low displacement-to-length ratio of 103.0 highlights its easily driven hull, which accelerates rapidly in light air and turns with precision. With a high sail area-to-displacement ratio of 22.04, the 670 has plenty of horsepower to windward and performs beautifully under a spinnaker. This lively character is balanced by a ballast-to-displacement ratio of 25.58%. While the boat tracks well with the keel fully lowered to its 3.9-foot maximum draft, its light overall weight of 1,896 pounds means it is susceptible to rolling. This is reflected in a low comfort ratio of 10.14 and a capsize screening ratio of 2.34. At anchor or under power with the keel fully retracted, the hull is sensitive to crew weight distribution and passing boat wakes, making it essential to keep the keel partially lowered when moored in busy waterways.
Known Issues & Triage
The primary technical point of inspection on any vintage Timpenny 670 is the keel lifting system. Because the drop-keel is a solid, heavy 485-pound plate, raising and lowering it puts significant stress on the manual winch, wire cables, and guide pulleys. Over time, these stainless steel cables can fray inside the enclosed keel trunk, leading to sudden failure. Regular inspection of the winch mounts, cable termination points, and pulley sheaves is crucial. The keel trunk itself should also be checked for fiberglass stress fractures near the pivot points, which can occur from previous groundings. As with many balsa- or plywood-cored decks of this era, owners must also watch for soft spots around the chainplates, stanchion bases, and the mast step. If the original sealant has failed, water can seep into the deck core, requiring localized recoring and hardware re-bedding.
Modernization & Upgrades
Modern owners frequently update the deck layout to maximize single-handed capabilities. Common retrofits include installing self-tacking jib tracks and leading all halyards and reefing lines aft to the cockpit using modern clutches. To alleviate the physical strain of lifting the heavy ballast plate, some owners have successfully replaced the high-purchase manual block-and-tackle systems with modern, compact electric winches. The boat's light displacement also makes it an ideal candidate for electric propulsion conversions. Swapping out a heavy, legacy two-stroke outboard for a lightweight electric outboard saves weight on the transom, improves the boat's natural sailing trim, and removes the odor and hazard of carrying portable fuel tanks in the cockpit lockers. For technical guidance and documentation, owners often refer to resources provided by the Timpenny Trailable Yacht Association of Australia.
The Verdict
The Timpenny 670 remains an exceptionally designed classic trailer sailer that offers a rewarding, dinghy-like sailing experience with the basic overnight comforts of a pocket yacht.
Pros:
- Outstanding light-air performance and highly responsive helm feel.
- Efficient interior layout with a functional saloon table integrated around the keel trunk.
- Lightweight and easy to tow, launch, and retrieve compared to larger 25-foot trailer yachts.
- Strong, active class association providing robust community support and parts sourcing.
Cons:
- Low comfort ratio results in noticeable rolling and motion when subjected to wakes at anchor.
- The heavy 485-pound ballast plate requires substantial physical effort to raise manually.
- Strict coastal and inland limits due to a high capsize screening ratio of 2.34.
- Keel lift cables and internal trunk hardware require meticulous, ongoing maintenance.
