Review of Granada 31
Basic specs.
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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. And outside the sailing season, just bottom cleaning and perhaps anti-fouling painting once a year - a few hours of work, that's all.
Both the hull and the deck is a sandwich construction 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 core material in the sandwich construction is balsa.
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 6 berths, a galley, 105.0 liter fresh water capacity and toilet facility.
The Granada 31 is built 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.
Fin keel
The Granada 31 is built 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 enter most marinas as the draft is just about 1.75 - 1.85 meter (5.74 - 6.04 ft) dependent on the load. See immersion rate below.
Granada 31 may be equipped with an inboard Volvo Penta MD7A diesel engine at 13 hp (9 kW). The speed is 7.0 knots.
The transmission is a saildrive.
The fuel tank, which is made of steel, has a capacity of 40.0 liters (10 US gallons, 8 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 Granada 31 is 1.91, 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 6.6 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 Granada 31 is about 151 kg/cm, alternatively 845 lbs/inch.
Meaning: if you load 151 kg cargo on the boat then it will sink 1 cm.
Alternatively, if you load 845 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 Granada 31 is 21.6 - 25.2.
What is L/B (Length Beam Ratio)?
The l/b ratio for Granada 31 is 3.08.
The ballast ratio for Granada 31 is 39%.
What is Displacement Length Ratio?
The DL-ratio for Granada 31 is 269 which categorizes this boat among 'light crusers & offshore racers'.
What is SA/D (Sail Area Displacement ratio)?
The SA/D for Granada 31 with ISO 8666 reference sail is 15.2, with a 135% genua the SA/D is 18.1.
What is Relative Speed Performance?
The Relative Speed Performance for Granada 31 is 62
Maintenance
As balsa wood is used as sandwich core material special care must be taken in relation to work that require penetration of the sandwich construction in order to to prevent water to get in contact with the balsa wood. Otherwise the balsa wood will eventually rotten and be expensive/impossible to repair.
When buying anti-fouling bottom paint, it's nice to know how much to buy.
The surface of the wet bottom is about 27m2 (290 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.
Dimensions of sail for fractional rig.
Are your sails worn out? You might find your next sail here: Sails for Sale
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 | ||
| Mainsail halyard | 29.6 m | (96.9 feet) | 10 mm | (3/8 inch) |
| Jib/genoa halyard | 29.6 m | (96.9 feet) | 10 mm | (3/8 inch) |
| Spinnaker halyard | 29.6 m | (96.9 feet) | 10 mm | (3/8 inch) |
| Jib sheet | 9.4 m | (30.8 feet) | 12 mm | (1/2 inch) |
| Genoa sheet | 9.4 m | (30.8 feet) | 12 mm | (1/2 inch) |
| Mainsheet | 23.5 m | (77.0 feet) | 12 mm | (1/2 inch) |
| Spinnaker sheet | 20.7 m | (67.8 feet) | 12 mm | (1/2 inch) |
| Cunningham | 3.2 m | (10.7 feet) | 10 mm | (3/8 inch) |
| Kickingstrap | 6.5 m | (21.3 feet) | 10 mm | (3/8 inch) |
| Clew-outhaul | 6.5 m | (21.3 feet) | 10 mm | (3/8 inch) |
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