Review of Nauticat 521
Basic specs.
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The hull is made of hand laid fibreglass while the deck is made of fibreglass. Generally, a hull made of hand laid fibreglass requires only a minimum of maintenance during the sailing season.
The hull is a double hull which improves the indoor climate. Especially when the water is colder than the air in the cabin, then the double hull insulates against cold water and reduce the condense water in the cabin.
The deck is a double deck which improves the indoor climate.
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 0 cabins, 7/10/11 berths, a galley, 1700.0 liter fresh water capacity and toilet facility.
The Nauticat 521 is equipped with a ketch rig. A ketch rig is generally considered easier to handle, because the sails are smaller, and because it can sail on most points to the wind with one sail completely taken down for repair or while reefing. The sail configuration of a ketch allows for better comfort and stability when sailing downwind or on a broad reach.
Fin keel
The Nauticat 521 is equipped with a fin keel. A boat with a fin keel is more manoeuvrable but has less directional stability than a similar boat with a full 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.
Nauticat 521 may be equipped with an inboard Ford engine at 130 hp (96 kW). The speed is 10.0 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.
The fuel tank, which is made of stainless steel, has a capacity of 2000.0 liters (528 US gallons, 439 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 Nauticat 521 is 1.61, 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 8.4 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 Nauticat 521 is about 372 kg/cm, alternatively 2088 lbs/inch.
Meaning: if you load 372 kg cargo on the boat then it will sink 1 cm.
Alternatively, if you load 2088 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 Nauticat 521 is 50.6.
What is L/B (Length Beam Ratio)?
The l/b ratio for Nauticat 521 is 3.39.
The ballast ratio for Nauticat 521 is 32%.
What is Displacement Length Ratio?
The DL-ratio for Nauticat 521 is 377 which categorizes this boat among 'heavy cruisers'.
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): 18.45
Maintenance
When buying anti-fouling bottom paint, it's nice to know how much to buy.
The surface of the wet bottom is about 62m2 (667 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 | 15.6 m | (51.2 feet) | 16 mm | (5/8 inch) |
| Genoa sheet | 15.6 m | (51.2 feet) | 16 mm | (5/8 inch) |
| Mainsheet | 39.0 m | (128.0 feet) | 16 mm | (5/8 inch) |
| Spinnaker sheet | 34.3 m | (112.6 feet) | 16 mm | (5/8 inch) |
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