Review of Guyline 105

Guyline 105 anno 1984.

Basic specs.

The Guyline 105 is a sailboat designed by the Finnish maritime architect Guy-Christer Lönngren in the mid eighties. The Guyline 105 is built by the Finnish yard Guyline.

Looking for a new boat? Find a Guyline 105 or similar boat for sale

Rig

The Guyline 105 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.

Keel

Swing keel

The Guyline 105 is equipped with a swing keel. A swing keel is a pivoting lifting keel, allowing to sail both coastal and inland waters.

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 1.40 - 1.50 meter (4.59 - 4.89 ft) dependent on the load. See immersion rate below.

Engine

The boat may be equipped with an inboard Yanmar diesel engine at 28 hp (20 kW). Calculated max speed is about 7.1 knots

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 105 is 1.91, indicating that this boat could - if evaluated by this formula alone - 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 7.2 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 Guyline 105 is about 176 kg/cm, alternatively 990 lbs/inch.
Meaning: if you load 176 kg cargo on the boat then it will sink 1 cm. Alternatively, if you load 990 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 Guyline 105 is 21.1.

Comparing this ratio with similar sailboats show that it is more comfortable than 24% 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 Guyline 105 is 3.50.

Compared with other similar sailboats it is slimmer than 79% of all other designs. It seems that the designer has chosen a significantly more speedy hull design.

Ballast Ratio

What is a Ballast Ratio?

The ballast ratio for Guyline 105 is 35%.

This ballast ratio shows a righting moment that is higher than 24% of all similar sailboat designs. A righting moment (ability to resist heeling) significantly below average.

D/L (Displacement Length Ratio)

What is Displacement Length Ratio?

The DL-ratio for Guyline 105 is 163 which categorizes this boat among 'light racers'.

85% 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 Guyline 105 with ISO 8666 reference sail is 20.3, with a 135% genua the SA/D is 23.3.

The SA/D ratio indicates that it is faster than 90% of all similar sailboat designs in light wind.

Over- / underrigged

The Guyline 105 has more rig than 79% 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 105 is 73

The relative speed performance is 73 which means that a it is faster than 73% of all similar sailboat designs.

Maintenance

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 35m² (376 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 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	34.5 m	(113.4 feet)	10 mm	(3/8 inch)
Jib/genoa halyard	34.5 m	(113.4 feet)	10 mm	(3/8 inch)
Spinnaker halyard	34.5 m	(113.4 feet)	10 mm	(3/8 inch)
Jib sheet	10.5 m	(34.4 feet)	12 mm	(1/2 inch)
Genoa sheet	10.5 m	(34.4 feet)	12 mm	(1/2 inch)
Mainsheet	26.2 m	(86.1 feet)	12 mm	(1/2 inch)
Spinnaker sheet	23.1 m	(75.8 feet)	12 mm	(1/2 inch)
Cunningham	4.4 m	(14.4 feet)	10 mm	(3/8 inch)
Kickingstrap	8.8 m	(28.9 feet)	10 mm	(3/8 inch)
Clew-outhaul	8.8 m	(28.9 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 Guyline 105 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.