ALPA 11.50
Specifications
Hull
| LOA | 37.93 ft |
| LWL | 26.74 ft |
| Beam | 10.5 ft |
| Draft | 5.97 ft |
| Displacement | 13,669 lb |
| Ballast | 5,180.6 lb |
| Hull speed1.34·√LWL | 6.9 kn |
Rig & Sails
| Iforetriangle height | 43.3 ft |
| Jforetriangle base | 16.2 ft |
| Pmainsail luff | 37.72 ft |
| Emainsail foot | 10.72 ft |
| FLforestay | 16.2 ft |
| Mainsail | 569.1 sq ft |
| Jib (100%) | 350.7 sq ft |
| Spinnaker | 596.2 sq ft |
About the ALPA 11.50
S.A. (Reported) = Main + #1 Genoa. Thanks to 'rmanganaro' for providing important corrections. Sometimes attributed to S&S but actually designed 'in house'.
Designed by Danilo Cattadori and built by Alpa (ITA) from 1975–1979, the Alpa 11.50 is a 37.93 ft masthead sloop with a displacement of 13669.0 lb. While the exact hulls built count is unknown, the vessel is characterized by a heavy displacement hull form with a D/L ratio of 319.16 and a comfort ratio of 30.63.
- Best for:
- This boat suits coastal cruisers and those seeking a stable, comfortable passage-making experience, given its high comfort ratio and moderate sail area-to-displacement ratio of 22.52. It is less ideal for high-performance racing due to its heavy displacement and fin keel configuration.
- Bluewater capability:
- With a capsize ratio of 1.76 and a substantial ballast of 5180.6 lb, the Alpa 11.50 demonstrates strong inherent stability suitable for offshore passages, provided the critical issue of deck core integrity is addressed.
- Comparables:
- Comparable boats include other Italian-built heavy displacement cruisers from the mid-1970s, such as the Nautor's Swan 41 or similar designs by O'Dea, which share similar beam-to-length ratios and heavy ballast fractions. These boats are comparable because they prioritize sea-keeping and interior volume over pure speed.
Performance
ORC Performance Data(2 certificates)
Measured performance data from ORC (Offshore Racing Congress) certificates.
Polar Diagram
Boat speed (kn) vs. true wind angle. Source: ORC
Racing Ratings
Triple Number
ORC Measured
Sail Areas (ORC)
Speed Table (kn)
| TWA \ TWS | 4 | 6 | 8 | 10 | 12 | 14 | 16 | 20 | 24 |
|---|---|---|---|---|---|---|---|---|---|
| 52° | 3.4 | 4.6 | 5.5 | 6.1 | 6.4 | 6.6 | 6.7 | 6.7 | 6.7 |
| 60° | 3.6 | 4.9 | 5.7 | 6.3 | 6.7 | 6.8 | 6.9 | 7.0 | 7.0 |
| 75° | 3.8 | 5.0 | 5.9 | 6.5 | 6.8 | 7.1 | 7.2 | 7.3 | 7.3 |
| 90° | 3.6 | 5.0 | 6.0 | 6.6 | 6.9 | 7.2 | 7.3 | 7.6 | 7.7 |
| 110° | 3.7 | 5.1 | 6.2 | 6.9 | 7.3 | 7.5 | 7.7 | 8.0 | 8.1 |
| 120° | 3.6 | 5.0 | 6.1 | 6.8 | 7.2 | 7.6 | 7.8 | 8.3 | 8.6 |
| 135° | 3.2 | 4.5 | 5.6 | 6.5 | 7.0 | 7.4 | 7.7 | 8.4 | 9.1 |
| 150° | 2.6 | 3.8 | 4.9 | 5.7 | 6.4 | 6.9 | 7.2 | 7.8 | 8.4 |
| Beat VMG | 2.2 | 3.0 | 3.7 | 4.1 | 4.4 | 4.5 | 4.6 | 4.6 | 4.5 |
| Run VMG | 2.3 | 3.3 | 4.2 | 5.0 | 5.6 | 6.0 | 6.4 | 7.0 | 7.5 |
Market Price
Estimated Cost of Ownership
Based on 37.93ft LOA. Actual costs vary by condition, usage, and local rates.
Known Issues & Pre-Purchase Inspection
3 reported issues across 2 systems for the ALPA 11.50, compiled from owner reports in sailing forums and owner-association material.
Unlock the full inspection report
Thinking of buying a ALPA 11.50? This is an in-depth report on the faults this model is known for — so you know exactly what to check when you walk the boat. For the price of a coffee.
- ✓ All 3 specific issues — severity, symptoms & fixes
- ✓ Model-specific pre-purchase inspection checklist
- ✓ Downloadable PDF to take to your surveyor — yours to keep
One-time $2.99 · secure checkout by Stripe · instant access · 30 days online, PDF yours to keep
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