With a fin keel and transom-hung rudder, the A27 is best understood as a compact coastal cruiser-racer rather than a bluewater passagemaker. Her design ratios support that assessment.
Design and Construction
The A27 has a solid-fiberglass hull and a deck built with a balsa-core sandwich. She displaces 6,459 pounds and carries 2,296 pounds of lead ballast. That gives her a ballast ratio of 35 percent and a reasonably firm stance for a boat of this size.
Her length-to-beam ratio is 2.79, while the displacement-length ratio is 237. That figure places her among moderate racers rather than heavy-displacement cruisers.
The capsize screening value is 2.06, below the threshold accepted for ocean racing. This reflects the boat’s coastal orientation rather than identifying a defect.
Rig and Sail Plan
The A27 carries a masthead-sloop rig with 384 square feet of sail area. Her sail-area-to-displacement ratio is 17.7 with the reference sail and rises to 21.2 with a 135 percent genoa.
Yacht Database reports that she carries more rig than 82% of all similar sailboats. That makes her significantly overrigged for her size, favoring acceleration in light air but demanding more attentive rig management.
The running rigging follows period dimensions:
- Mainsail, jib, and spinnaker halyards: 27 meters at 8 mm
- Jib and genoa sheets: 8.2 meters at 10 mm
- Mainsheet: 20.4 meters at 10 mm
Handling and Performance
The A27 measures 26.82 feet overall, with a 23-foot waterline and a theoretical hull speed of 6.4 knots.
Her immersion rate is about 770 pounds per inch, so changes in load will show visibly in her draft and freeboard. Depending on load, the fin keel draws between 5.25 and 5.55 feet. That keeps her out of the thinnest shoals but allows access to most marinas.
A Motion Comfort Ratio of 20.2 points to a comparatively brisk, less damped motion than that of heavier cruisers, consistent with her moderate-racer classification.
Accommodations
The available material doesn’t provide an interior arrangement, berth count, or tankage figures for the A27. The known dimensions—a 9.61-foot beam and 27-foot length—frame a compact, two-person coastal interior typical of the era’s small Sparkman & Stephens cruisers, but no sourced description of the layout exists.
Known Issues
No construction defects, systemic failures, or recurring owner-reported faults have been established for the A27.
The Verdict
The Alpa A27 is a small, overrigged coastal sloop from a respected design office. She combines a solid-fiberglass hull, balsa-cored deck, and lead-ballasted fin keel with a sail plan that favors quick acceleration and light-air performance.
She should fit into most marina berths, but her capsize-screening and motion-comfort figures mark her as a fair-weather coastal boat rather than a passagemaker.
Pros
- Sparkman & Stephens design with a 35 percent ballast ratio and a firm stance
- Significantly overrigged for her size, favoring light-air performance
- Moderate draft allows access to most marina berths
Cons
- Capsize screening value of 2.06 falls outside ocean-racing acceptance
- Low Motion Comfort Ratio indicates a brisk, less damped ride
- No sourced interior or tankage details are available for evaluation
