Review of Guyline 125

Basic specs.

The Guyline 125 is a large sailboat designed by the Finnish maritime architect Guy-Christer Lönngren in the early eighties.

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Interior

The boat is equipped with 8 berths.

Rig

The boat 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 genaker or a spinnaker for optimal speed.

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 even shallow marinas as the draft is just about 1.10 - 1.20 meter (3.61 - 3.91 ft) dependent on the load. See immersion rate below.

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 Guyline 125 is 1.90, indicating that this boat could - if evaluated by this formula alone - be accepted to participate in ocean races.

Immersion rate

The immersion rate is defined as the weight required to sink the boat a certain level. The immersion rate for Guyline 125 is about 273 kg/cm, alternatively 1528 lbs/inch.
Meaning: if you load 273 kg cargo on the boat then it will sink 1 cm. Alternatively, if you load 1528 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.

L/B (Length Beam Ratio)

What is L/B (Length Beam Ratio)?

The l/b ratio for Guyline 125 is 3.83.

Compared with other similar sailboats it is slimmer than 93% of all other designs. It seems that the designer has chosen a significantly more speedy hull design. This type of design is also referred to as 'needle'.

Ballast Ratio

What is a Ballast Ratio?

The ballast ratio for Guyline 125 is 35%.

This ballast ratio shows a righting moment that is higher than 27% of all similar sailboat designs. A righting moment (ability to resist heeling) just below average.

SA/D (Sail Area Displacement ratio)

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

The SA/D for Guyline 125 with ISO 8666 reference sail is 20.2, with a 135% genua the SA/D is 23.4.

The SA/D ratio indicates that it is faster than 85% of all similar sailboat designs in light wind.

Over- / underrigged

The Guyline 125 has more rig than 99% of all similar sailboats, which indicates that the boat is significantly overrigged.

RSP (Relative Speed Performance)

What is Relative Speed Performance?

The Relative Speed Performance for Guyline 125 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 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.

**Guiding dimensions of running rig**
Usage	Length		Diameter
Mainsail halyard	36.8 m	(120.7 feet)	12 mm	(1/2 inch)
Jib/genoa halyard	36.8 m	(120.7 feet)	12 mm	(1/2 inch)
Spinnaker halyard	36.8 m	(120.7 feet)	12 mm	(1/2 inch)
Jib sheet	12.5 m	(41.0 feet)	14 mm	(0.55 inch)
Genoa sheet	12.5 m	(41.0 feet)	14 mm	(0.55 inch)
Mainsheet	31.2 m	(102.5 feet)	14 mm	(0.55 inch)
Spinnaker sheet	27.5 m	(90.2 feet)	14 mm	(0.55 inch)
Cunningham	4.7 m	(15.4 feet)	12 mm	(1/2 inch)
Kickingstrap	9.4 m	(30.8 feet)	12 mm	(1/2 inch)
Clew-outhaul	9.4 m	(30.8 feet)	12 mm	(1/2 inch)

Boat owner's ideas

This section shown boat owner's changes, improvements, etc. Here you might find inspiration for your boat.

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Finally

We are always looking for new photos. If you can contribute with photos for Guyline 125 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.