Review of Najad 520 DS
Basic specs.
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The boat is equipped with a galley and 1000.0 liter fresh water capacity.
The Najad 520 DS 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.
Unknown keel type
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.
Najad 520 DS may be equipped with an inboard Yanmar 4LH-HTE diesel engine at 135 hp (100 kW). Calculated max speed is about 8.7 knots
The fuel tank has a capacity of 690.0 liters (182 US gallons, 151 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 Najad 520 DS is 1.71, 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 8.9 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 Najad 520 DS is about 417 kg/cm, alternatively 2338 lbs/inch.
Meaning: if you load 417 kg cargo on the boat then it will sink 1 cm.
Alternatively, if you load 2338 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 Najad 520 DS is 39.0.
What is L/B (Length Beam Ratio)?
The l/b ratio for Najad 520 DS is 3.43.
The ballast ratio for Najad 520 DS is 34%.
What is Displacement Length Ratio?
The DL-ratio for Najad 520 DS is 224 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): 14.63
Maintenance
When buying anti-fouling bottom paint, it's nice to know how much to buy.
The surface of the wet bottom is about 69m2 (742 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 | 15.8 m | (51.8 feet) | 16 mm | (5/8 inch) |
| Genoa sheet | 15.8 m | (51.8 feet) | 16 mm | (5/8 inch) |
| Mainsheet | 39.5 m | (129.6 feet) | 16 mm | (5/8 inch) |
| Spinnaker sheet | 34.8 m | (114.0 feet) | 16 mm | (5/8 inch) |
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