Review of Guy 27

Guy 27 anno 1987.

Basic specs.

The Guy 27 is a sailboat designed by the Finnish maritime architect Guy-Christer Lönngren in the late seventies.

Looking for a new boat? Find a Guy 27 or similar boat for sale

Interior

The boat is equipped with 4 berths, a galley and toilet facility.

Rig

The boat has more than one rig.

One option is 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 genaker or a spinnaker for optimal speed.

Another option is 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.

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 Guy 27 is 2.21, 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 6.2 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 Guy 27 is about 122 kg/cm, alternatively 683 lbs/inch.
Meaning: if you load 122 kg cargo on the boat then it will sink 1 cm. Alternatively, if you load 683 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 Guy 27 is 15.4.

Comparing this ratio with similar sailboats show that it is more comfortable than 21% of all similar sailboat designs. This is a comfort value significantly below average.

L/B (Length Beam Ratio)

What is L/B (Length Beam Ratio)?

The l/b ratio for Guy 27 is 2.99.

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.

D/L (Displacement Length Ratio)

What is Displacement Length Ratio?

The DL-ratio for Guy 27 is 193 which categorizes this boat among 'light racers'.

73% 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 Guy 27 with ISO 8666 reference sail is 16.3, with a 135% genua the SA/D is 19.6.

The SA/D ratio indicates that it is faster than 54% of all similar sailboat designs in light wind.

RSP (Relative Speed Performance)

What is Relative Speed Performance?

The Relative Speed Performance for Guy 27 is 50

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

Maintenance

Rig

Dimensions of sail for masthead 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.

**Guiding dimensions of running rig**
Masthead rig
Usage	Length		Diameter
Mainsail halyard	23.4 m	(76.9 feet)	8 mm	(5/16 inch)
Jib/genoa halyard	23.4 m	(76.9 feet)	8 mm	(5/16 inch)
Spinnaker halyard	23.4 m	(76.9 feet)	8 mm	(5/16 inch)
Jib sheet	8.3 m	(27.1 feet)	10 mm	(3/8 inch)
Genoa sheet	8.3 m	(27.1 feet)	10 mm	(3/8 inch)
Mainsheet	20.6 m	(67.7 feet)	10 mm	(3/8 inch)
Spinnaker sheet	18.2 m	(59.6 feet)	10 mm	(3/8 inch)
Cunningham	2.4 m	(7.9 feet)	8 mm	(5/16 inch)
Kickingstrap	4.8 m	(15.7 feet)	8 mm	(5/16 inch)
Clew-outhaul	4.8 m	(15.7 feet)	8 mm	(5/16 inch)
Fractional rig
Usage	Length		Diameter
Mainsail halyard	23.8 m	(78.1 feet)	8 mm	(5/16 inch)
Jib/genoa halyard	23.8 m	(78.1 feet)	8 mm	(5/16 inch)
Spinnaker halyard	23.8 m	(78.1 feet)	8 mm	(5/16 inch)
Jib sheet	8.3 m	(27.1 feet)	10 mm	(3/8 inch)
Genoa sheet	8.3 m	(27.1 feet)	10 mm	(3/8 inch)
Mainsheet	20.6 m	(67.7 feet)	10 mm	(3/8 inch)
Spinnaker sheet	18.2 m	(59.6 feet)	10 mm	(3/8 inch)
Cunningham	3.0 m	(9.8 feet)	8 mm	(5/16 inch)
Kickingstrap	6.0 m	(19.7 feet)	8 mm	(5/16 inch)
Clew-outhaul	6.0 m	(19.7 feet)	8 mm	(5/16 inch)

Boat owner's ideas

This section is reserved boat owner's changes, 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 Guy 27 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

[Ref 1]: ISO 8666 Small craft — Principal data.
[Ref 3]: ISO 12215-5 Small craft — Hull construction and scantlings.