Review of Castle 550
Basic specs.
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The hull is made of fibreglass. Generally, a hull made of fibreglass requires only a minimum of maintenance during the sailing season. And outside the sailing season, just bottom cleaning and perhaps anti-fouling painting once a year - a few hours of work, that's all.
The Castle 550 is equipped with a fractional rig. A fractional rig has smaller headsails which make tacking easier, which is an advantage for cruisers and racers, of course. The downside is that having the wind from behind often requires a gennaker or a spinnaker for optimal speed.
DaggerBoard aka Sword
The Castle 550 is equipped with a daggerboard keel. A daggerboard is a lifting keel that can be lowered and raised, allowing the boat to enter shallow waters as well.
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 Castle 550 is 3.05, indicating that this boat would not 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 5.4 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 Castle 550 is about 78 kg/cm, alternatively 439 lbs/inch.
Meaning: if you load 78 kg cargo on the boat then it will sink 1 cm.
Alternatively, if you load 439 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 Castle 550 is 6.5.
What is L/B (Length Beam Ratio)?
The l/b ratio for Castle 550 is 2.28.
The ballast ratio for Castle 550 is 25%.
What is Displacement Length Ratio?
The DL-ratio for Castle 550 is 119 which categorizes this boat among 'ultra light racers'.
Maintenance
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 | 5.5 m | (18.0 feet) | 8 mm | (5/16 inch) |
| Genoa sheet | 5.5 m | (18.0 feet) | 8 mm | (5/16 inch) |
| Mainsheet | 13.7 m | (44.9 feet) | 8 mm | (5/16 inch) |
| Spinnaker sheet | 12.1 m | (39.6 feet) | 8 mm | (5/16 inch) |
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