Design and Construction
Sparkman & Stephens drew the 12.70 as one of the best Sparkman & Stephens projects of its period. Sparkman & Stephens drew a well-proportioned, fin-keel masthead sloop, and Alpa built her with great care at its own construction site. Only 15 examples were produced.
The hull and deck are solid fiberglass. At 41.5 feet overall, the boat has an 11.42-foot beam, a 6.82-foot draft, and a displacement of 18,637 pounds. She carries 9,700 pounds of lead ballast, giving her a 52 percent ballast-displacement ratio. Her capsize screening number is 1.72, and her comfort ratio is 33.66.
The deckhouse is one of the class’s distinguishing features. Alpa offered long- and short-deckhouse versions, but built only four boats with the short deckhouse. Those four are regarded as small masterpieces in their own right, reflecting both the rarity and the finely resolved form of the shorter trunk configuration.
Rig and Handling
The Alpa 12.70 won offshore races in her day. That record speaks to her sail plan and the hull’s behavior under load rather than to any concession to comfort.
Her masthead sloop rig carries 788 square feet of sail. Combined with her displacement, that produces a sail-area-to-displacement ratio of 17.93—modest by modern light-air standards, but well matched to the 7.33-knot hull speed suggested by her 29.92-foot waterline. A fin keel and skeg-hung rudder place her firmly in the performance-cruiser lineage that Sparkman & Stephens refined through the late 1960s.
Accommodations
Available descriptions distinguish between the two deckhouse layouts rather than detailing the cabins. The principal dimensions therefore tell the accommodation story in broad terms. A 41.5-foot hull with a 3.48-meter (11.42-foot) beam and 100 gallons of water capacity implies the cruising volume expected of a boat this size, which the long-deckhouse version would have exploited most fully.
The four short-deckhouse boats represent the more driver-oriented version of the same platform.
Known Issues
No structural defects, osmotic problems, rigging failures, or systemic construction faults are associated with the class.
Verdict
The Alpa 12.70 is a rare, carefully built Sparkman & Stephens design that earned offshore racing credentials without sacrificing the cruising volume implied by her size. With only 15 built—and just four in the coveted short-deckhouse form—she is a collector-grade example of late-1960s Italian GRP craftsmanship.
Pros
- Considered one of the best Sparkman & Stephens designs of its period
- Built by Alpa with notable care
- Proven offshore race winner in her era
- Only 15 examples produced
- Rare short-deckhouse version—four built—is considered a small masterpiece
Cons
- Very limited production restricts spares commonality and class support
- Modest sail-area-to-displacement ratio by modern light-air standards
