Review of Swan 391
Basic specs.
If you have a photo you would like to share: Upload Image
Looking for a new boat? Find a Swan 391 or similar boat for sale
Both the hull and the deck is made of fibreglass. Generally, a hull made of fibreglass requires only a minimum of maintenance during the sailing season.
The interior is like most other boats made of teak. Teak has the advantage of being naturally very oily and therefore water-repellent, which is suitable on boats.
The boat is equipped with 8 berths, a galley, 300.0 liter fresh water capacity and toilet facility.
The Swan 391 is equipped with a masthead rig. The advantage of a masthead rig is its simplicity and the fact that a given sail area - compared with a fractional rig - can be carried lower and thus with less heeling moment.
Fin keel
The Swan 391 is equipped with a fin keel. The fin keel is the most common keel and provides splendid manoeuvrability. The downside is that it has less directional stability than a long keel.
The keel is made of lead. Compared with iron, lead has the advantage of being 44% heavier, which allows a smaller keel and hence less water resistance and higher speed.
The boat can only enter major marinas as the draft is about 2.20 - 2.30 meter (7.22 - 7.52 ft) dependent on the load. See immersion rate below.
The Swan 391 has been equipped with different engine alternatives.
Alternative 1:
Swan 391 may be equipped with an inboard Perkins 4.108 diesel engine at 40 hp (29 kW). The speed is 8.1 knots.
The transmission is a shaft drive. A shaft drive will in the long run require less maintenance than other types of drive e.g. a sail drive.
Alternative 2:
The boat may be equipped with an inboard Perkins diesel engine
The fuel tank, which is made of stainless steel, has a capacity of 180.0 liters (47 US gallons, 39 imperial gallons).
Sailing characteristics
This section covers widely used rules of thumb to describe the sailing characteristics. Please note that even though the calculations are correct, the interpretation of the results might not be valid for extreme boats.
What is Capsize Screening Formula (CSF)?
The capsize screening value for Swan 391 is 1.88, indicating that this boat could - if evaluated by this formula alone - be accepted to participate in ocean races.
What is Theoretical Maximum Hull Speed?
The theoretical maximal speed of a displacement boat of this length is 7.7 knots. The term "Theoretical Maximum Hull Speed" is widely used even though a boat can sail faster. The term shall be interpreted as above the theoretical speed a great additional power is necessary for a small gain in speed.
The immersion rate is defined as the weight required to sink the boat a certain level.
The immersion rate for Swan 391 is about 256 kg/cm, alternatively 1438 lbs/inch.
Meaning: if you load 256 kg cargo on the boat then it will sink 1 cm.
Alternatively, if you load 1438 lbs cargo on the boat it will sink 1 inch.
Sailing statistics
This section is statistical comparison with similar boats of the same category. The basis of the following statistical computations is our unique database with more than 26,000 different boat types and 350,000 data points.
What is Motion Comfort Ratio (MCR)?
The Motion Comfort Ratio for Swan 391 is 28.4.
What is L/B (Length Beam Ratio)?
The l/b ratio for Swan 391 is 3.21.
The ballast ratio for Swan 391 is 36%.
What is Displacement Length Ratio?
The DL-ratio for Swan 391 is 230 which categorizes this boat among 'light crusers & offshore racers'.
SA/D (Sail Area Displacement ratio)
Indicates how fast the boat is in light wind:
- Cruising Boats have ratios 10-15
- Cruiser-Racers have ratios 16-20
- Racers have ratios above 20
- High-Performance Racers have ratios above 24
Sail-area/displacement ratio (SA/D ratio): 19.53
Maintenance
When buying anti-fouling bottom paint, it's nice to know how much to buy.
The surface of the wet bottom is about 45m2 (484 ft2).
Based on this, your favourite maritime shop can tell you the quantity you need.
Note: If you use a paint roller you will need more paint than if you use a paintbrush.
If you need to renew parts of your running rig and is not quite sure of the dimensions, you may find the estimates computed below useful.
| Usage | Length | Diameter | ||
| Jib sheet | 12.2 m | (40.0 feet) | 14 mm | (0.55 inch) |
| Genoa sheet | 12.2 m | (40.0 feet) | 14 mm | (0.55 inch) |
| Mainsheet | 30.5 m | (100.0 feet) | 14 mm | (0.55 inch) |
| Spinnaker sheet | 26.8 m | (88.0 feet) | 14 mm | (0.55 inch) |
This section is reserved boat owner's modifications, improvements, etc. Here you might find (or contribute with) inspiration for your boat.
Do you have changes/improvements you would like to share? Upload a photo and describe what you have done.
We are always looking for new photos. If you can contribute with photos for Swan 391 it would be a great help.
If you have any comments to the review, improvement suggestions, or the like, feel free to contact us. Criticism helps us to improve.