Design and Construction
Sparkman & Stephens laid out the 42 around a 39-foot-4-inch hull on a 37-foot-6-inch waterline, with a beam of just 11 feet 3 inches. That 3.50 length-to-beam ratio makes her slimmer than 69 percent of comparable designs, a figure that reads as a deliberate cruising compromise rather than a racer's hull. Her 26,455-pound displacement and 9,920 pounds of lead ballast give a 38-percent ballast ratio, higher than 42 percent of similar boats, and a displacement-length ratio of 223 places her among what one design database terms "moderate racers" — 66% of similar sailboat designs are categorized as heavier. The hull is solid fiberglass with a fin keel and skeg-hung rudder, with loaded draft ranging from 6 feet 1 inch to 6 feet 4 inches.
Rig and Handling
The 42 carries a ketch rig with a modest 764 square feet of sail area, leaving her with more rig than only 12 percent of similar sailboats — a significant underrigged condition by the numbers. The standing and running gear follows period ketch practice: mainsail and jib/genoa halyards of about 111 feet at a half-inch diameter, sheets around 39 feet for the headsails and 98 feet for the mainsail at roughly nine-sixteenths inch, and a spinnaker halyard matching the 111-foot length. Her wetted surface runs about 484 square feet, and the immersion rate is a substantial 1,473 pounds per inch, so she sits heavily and moves ballast and load with measurable effect on trim.
Performance Profile
On paper the 42 is a comfortable sea boat. Her Motion Comfort Ratio of 42.4 is said to exceed 96 percent of similar designs, and a capsize screening value of 1.51 would, by that formula alone, admit her to ocean racing. Theoretical hull speed is 8.2 knots. These indices argue for a stable, easy-riding hull rather than a lively performer, consistent with the slender, moderately ballasted cruiser her dimensions describe.
Accommodations and Layout
The known record describes the 42 as a large sailboat built in small numbers, with the ketch rig and solid fiberglass construction. Beyond the principal dimensions, the sources do not itemize berth counts, joinery, or galley arrangement, so the interior must be judged on viewing rather than described from the record.
The Verdict
The Alpa 42 is a narrowly produced, strongly pedigreed Mediterranean cruiser whose slender hull and heavy comfort index mark her as a stable offshore companion rather than a swift coastal racer. Her ketch rig and modest sail area suit a methodical crew, and the Sparkman & Stephens lineage gives her a place in the design history that outruns her rarity.
Pros
- Sparkman & Stephens design with a documented comfort ratio exceeding 96% of similar boats
- Solid fiberglass hull with lead ballast and a fin-keel/skeg-rudder underbody
- Capsize screening and comfort figures that support bluewater use
Cons
- Significantly underrigged for her size, with sail area low against peers
- Very small production run limits parts, class knowledge, and resale liquidity
- Sparse documented specification beyond principal dimensions and rig
