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Review of Granada 31


Granada 31
Granada 31 anno 1980. Granada 31 from the masthead


Basic specs.

sail specifications
The Granada 31 is a sailboat designed by the maritime architect bureau Elvstrøm & Kjærulff in the late seventies. Several hundred boats have been produced. The Granada 31 is built by the Danish yard Gesten Glasfiber Bådeværft.

Looking for a new boat? Find a Granada 31 or similar boat for sale

Hull

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.

The hull 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.


Interior

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, 100.0 liter fresh water capacity and toilet facility.

Note: the boat has also been sold to be self-made/-interiored, which means that the quality of each boat may vary.


Rig

The Granada 31 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.


Keel
Keel
Keel of Granada 31 anno 1987. On lake Neuchatel, Switzerland

Fin keel

The Granada 31 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 iron. Many people prefer lead keel in favour of iron. The main argument is that lead is much heavier than iron and a lead keel can therefore be made smaller which again result in less wet surface, i.e. less drag. In fact iron is quite heavy, just 30% less heavy than lead, so the advantage of a lead keel is often overstated. As the surface of a fin type keel is just a fraction of the total wet surface, the difference between an iron keel and a lead keel can in reality be ignored for cruising yachts.

Granada 31 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.


Engine

The boat may be equipped with an inboard Volvo Penta MD7 diesel engine at 13 hp (9 kW). Calculated max speed is about 4.7 knots

The transmission is a saildrive.

The fuel tank, which is made of stainless steel, has a capacity of 50.0 liters (13 US gallons, 10 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.

Stability and Safety

What is Capsize Screening Formula (CSF)?

The capsize screening value for Granada 31 is 2.01, indicating that this boat would not be accepted to participate in ocean races.


Theoretical Maximum Hull Speed

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.


Immersion rate

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.

Motion Comfort Ratio

What is Motion Comfort Ratio (MCR)?

The Motion Comfort Ratio for Granada 31 is 21.6.

Low High 38% 0 50 100
Comparing this ratio with similar sailboats show that it is more comfortable than 38% of all similar sailboat designs. This comfort value is just below average.


L/B (Length Beam Ratio)

What is L/B (Length Beam Ratio)?

The l/b ratio for Granada 31 is 3.08.

Slim Wide 58% 0 50 100
Compared with other similar sailboats it is more spacy than 58% of all other designs. It seems that the designer has chosen a slightly more spacy hull design.


Ballast Ratio

What is a Ballast Ratio?

The ballast ratio for Granada 31 is 40%.

Low High 46% 0 50 100
This ballast ratio shows a righting moment that is higher than 46% of all similar sailboat designs. A righting moment (ability to resist heeling) just below average.


D/L (Displacement Length Ratio)

What is Displacement Length Ratio?

The DL-ratio for Granada 31 is 248 which categorizes this boat among 'light crusers & offshore racers'.

Heavy Light 54% 0 50 100
54% of all similar sailboat designs are categorized as heavier. A light displacement requires less sailarea and has higher accellerations.


SA/D (Sail Area Displacement ratio)

What is SA/D (Sail Area Displacement ratio)?

The SA/D for Granada 31 with ISO 8666 reference sail is 16.9, with a 135% genua the SA/D is 20.0.

Low High 58% 0 50 100
The SA/D ratio indicates that it is faster than 58% of all similar sailboat designs in light wind.


Over- / underrigged

Low High 38% 0 50 100
The Granada 31 has more rig than 38% of all similar sailboats, which indicates that the boat is slightly underrigged.


RSP (Relative Speed Performance)

What is Relative Speed Performance?

The Relative Speed Performance for Granada 31 is 62

Slow Fast 62% 0 50 100
The relative speed performance is 62 which means that a it is faster than 62% of all similar sailboat designs.


Maintenance

Hull / Deck

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.

Bottom Paint

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.


Rig

Dimensions of sail for masthead rig.

mainsail specifications genoa specifications spinnaker specifications

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.



Guiding dimensions of running rig
UsageLengthDiameter
Mainsail halyard 29.6 m(96.9 feet)10 mm(3/8 inch)
Jib/genoa halyard29.6 m(96.9 feet)10 mm(3/8 inch)
Spinnaker halyard29.6 m(96.9 feet)10 mm(3/8 inch)
Jib sheet 9.4 m(30.8 feet)12 mm(1/2 inch)
Genoa sheet9.4 m(30.8 feet)12 mm(1/2 inch)
Mainsheet 23.5 m(76.9 feet)12 mm(1/2 inch)
Spinnaker sheet20.6 m(67.7 feet)12 mm(1/2 inch)
Cunningham3.2 m(10.7 feet)10 mm(3/8 inch)
Kickingstrap6.5 m(21.3 feet)10 mm(3/8 inch)
Clew-outhaul6.5 m(21.3 feet)10 mm(3/8 inch)

Boat owner's ideas

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.



Finally

We are always looking for new photos. If you can contribute with photos for Granada 31 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.



References