DOLPHIN 31
Specifications
Hull
| LOA | 31 ft |
| LWL | 26.51 ft |
| Beam | 10.33 ft |
| Draft | 4.82 ft |
| Displacement | 8,752 lb |
| Ballast | 2,396.3 lb |
| Hull speed1.34·√LWL | 6.9 kn |
About the DOLPHIN 31
Plan A has 'pullman' (2 tier) quarter berths aft with starboard-facing chart table. Plan B has convertible dinette. Thanks to DOLPHIN 31 owner Ari H. for providing additional information.
Designed by John Sharp and built by Carlisle & Williams (UK)/Rank Marine Int. (UK), the Dolphin 31 is a rare vessel with only 55 hulls built in 1977. This limited production run creates a unique market position for this 31.0 ft masthead sloop, characterized by a displacement of 8752.0 lb and a beam of 10.33 ft.
- Best for:
- This boat suits coastal cruisers and short-handed sailors who prioritize a comfortable motion, evidenced by a comfort ratio of 21.65, over high-performance racing. Its moderate displacement and fin keel configuration make it well-suited for protected waters and moderate offshore passages.
- Bluewater capability:
- With a capsize ratio of 2.01 and a displacement/length ratio of 209.72, the Dolphin 31 demonstrates adequate stability for offshore cruising, though its single-year production and specific structural vulnerabilities require careful vetting for serious bluewater use.
- Comparables:
- Comparable boats from this era include the Hallberg-Rassy 31 and the O'Day 32, which share similar displacement ranges and coastal cruising roles. These vessels offer similar interior volumes and stability characteristics, though the Dolphin 31's specific John Sharp design provides a distinct handling profile.
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 |
|---|---|---|---|---|---|---|---|
| 52° | 4.5 | 5.4 | 5.9 | 6.1 | 6.3 | 6.4 | 6.4 |
| 60° | 4.8 | 5.6 | 6.0 | 6.3 | 6.4 | 6.5 | 6.6 |
| 75° | 4.9 | 5.7 | 6.1 | 6.4 | 6.6 | 6.7 | 6.9 |
| 90° | 4.8 | 5.7 | 6.2 | 6.5 | 6.6 | 6.8 | 7.1 |
| 110° | 4.9 | 5.9 | 6.4 | 6.7 | 7.0 | 7.2 | 7.6 |
| 120° | 4.8 | 5.8 | 6.3 | 6.7 | 7.0 | 7.3 | 7.9 |
| 135° | 4.3 | 5.4 | 6.1 | 6.5 | 6.8 | 7.1 | 7.9 |
| 150° | 3.7 | 4.7 | 5.6 | 6.2 | 6.5 | 6.8 | 7.4 |
| Beat VMG | 3.0 | 3.6 | 4.1 | 4.4 | 4.5 | 4.6 | 4.7 |
| Run VMG | 3.2 | 4.1 | 4.8 | 5.5 | 6.0 | 6.4 | 7.0 |
Pricing
We don't have market pricing data for the DOLPHIN 31 yet. If you own one, help other buyers — what did you pay for it? Reports build a community price estimate over time.
Estimated Cost of Ownership
Based on 31ft LOA. Actual costs vary by condition, usage, and local rates.
Known Issues & Pre-Purchase Inspection
12 reported issues across 6 systems for the DOLPHIN 31, compiled from owner reports in sailing forums and owner-association material.
Unlock the full inspection report
Thinking of buying a DOLPHIN 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 12 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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Which engine powers your DOLPHIN 31?
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Brands sometimes mentioned for this model: Yanmar, Beta Marine, Petter, Volvo — is it one of these?
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Used sails that fit the DOLPHIN 31
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