MAMBA 31
Specifications
Hull
| LOA | 30.68 ft |
| LWL | 26.25 ft |
| Beam | 10.07 ft |
| Draft | 5.41 ft |
| Displacement | 7,716 lb |
| Ballast | 3,505.4 lb |
| Hull speed1.34·√LWL | 6.9 kn |
Rig & Sails
| Iforetriangle height | 38.39 ft |
| Jforetriangle base | 10.99 ft |
| Pmainsail luff | 33.79 ft |
| Emainsail foot | 9.84 ft |
| FLforestay | 11 ft |
| Mainsail | 390.5 sq ft |
| Jib (100%) | 211 sq ft |
| Spinnaker | 358.6 sq ft |
About the MAMBA 31
Designed as IOR 1/2 ton.
The Mamba 31 is a Swedish-built cruiser designed by Harry Becker, Rolf Magnusson, and Bengt Karlsson, constructed by BK Marin (SWE) with a total production of 250 hulls in 1978. This single-year production run represents a specific vintage of European design, characterized by its masthead sloop rig and fin keel configuration.
- Best for:
- This vessel suits coastal cruisers and those seeking a manageable, moderately light-displacement boat for weekend trips or short passages, given its 19.95 comfort ratio and 15.5 sail area-to-displacement ratio. It is less ideal for heavy-weather bluewater voyaging due to its relatively low displacement of 7716.0 lb and single-year production history which may limit parts availability.
- Bluewater capability:
- With a capsize ratio of 2.04 and a displacement of 7716.0 lb, the Mamba 31 offers moderate offshore capability suitable for protected waters and short open-sea crossings, but its light displacement and single-year production suggest caution for extended bluewater expeditions without significant structural reinforcement.
- Comparables:
- Comparable boats include other late-1970s European cruisers like the Hallberg-Rassy 31 or Nauticat 31, which share similar beam dimensions (10.07 ft) and displacement ranges. These vessels are comparable due to their shared era of design philosophy emphasizing interior volume and moderate performance over heavy offshore robustness.
Performance
ORC Performance Data(1 certificate)
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 | 6 | 8 | 10 | 12 | 14 | 16 | 20 | 24 |
|---|---|---|---|---|---|---|---|---|
| 52° | 4.3 | 5.2 | 5.8 | 6.2 | 6.3 | 6.5 | 6.5 | 6.5 |
| 60° | 4.6 | 5.5 | 6.0 | 6.3 | 6.5 | 6.6 | 6.7 | 6.7 |
| 75° | 4.7 | 5.6 | 6.2 | 6.5 | 6.7 | 6.8 | 7.0 | 7.1 |
| 90° | 4.8 | 5.8 | 6.3 | 6.7 | 6.8 | 6.9 | 7.2 | 7.4 |
| 110° | 4.8 | 5.9 | 6.5 | 6.8 | 7.1 | 7.3 | 7.8 | 8.0 |
| 120° | 4.7 | 5.7 | 6.4 | 6.8 | 7.1 | 7.4 | 8.0 | 8.6 |
| 135° | 4.2 | 5.3 | 6.1 | 6.5 | 6.9 | 7.2 | 7.8 | 8.6 |
| 150° | 3.6 | 4.6 | 5.4 | 6.0 | 6.3 | 6.6 | 7.0 | 7.5 |
| Beat VMG | 2.8 | 3.5 | 3.9 | 4.3 | 4.5 | 4.6 | 4.6 | 4.5 |
| Run VMG | 3.1 | 4.0 | 4.7 | 5.2 | 5.5 | 6.0 | 6.6 | 7.1 |
Market Price
Estimated Cost of Ownership
Based on 30.68ft LOA. Actual costs vary by condition, usage, and local rates.
Known Issues & Pre-Purchase Inspection
10 reported issues across 7 systems for the MAMBA 31, compiled from owner reports in sailing forums and owner-association material.
Unlock the full inspection report
Thinking of buying a MAMBA 31? 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 10 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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