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Review of Johnson 27


Johnson 27
Johnson 27 anno 1976.

Basic specs.

sail specifications
The Johnson 27 aka Clipper 29 is a sailboat designed by the Swedish maritime architect Bo Johnson. A few hundred boats have been produced. The Johnson 27 is built by the Swedish yard Johnson båtar AB.

Looking for a new boat? Find a Johnson 27 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.

Interior
The boat is equipped with a galley.
Note: the boat has also been sold to be self-made/-interiored, which means that the quality of each boat may vary.

Rig
The boat 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

The Johnson 27 is equipped with a fin keel. A boat with a fin keel is more manoeuvrable but has less directional stability than a similar boat with a long keel.

Johnson 27 can enter even shallow marinas as the draft is just about 1.30 - 1.40 meter (4.27 - 4.57 ft) dependent on the load. See immersion rate below.


Engine

The boat is typically equipped with an inboard Yanmar 12 diesel engine at 12.0 hp (8 kW), which gives a max speed about 4.8 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 Johnson 27 is 1.93, 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 6.4 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 Johnson 27 is about 126 kg/cm, alternatively 706 lbs/inch.
Meaning: if you load 126 kg cargo on the boat then it will sink 1 cm. Alternatively, if you load 706 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 Johnson 27 is 22.0.

Low High 58% 0 50 100
Comparing this ratio with similar sailboats show that it is more comfortable than 58% of all similar sailboat designs. This comfort value is just above average.


L/B (Length Beam Ratio)

What is L/B (Length Beam Ratio)?

The l/b ratio for Johnson 27 is 3.05.

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


D/L (Displacement Length Ratio)

What is Displacement Length Ratio?

The DL-ratio for Johnson 27 is 246 which categorizes this boat among 'light crusers & offshore racers'.

Heavy Light 50% 0 50 100
50% of all similar sailboat designs are categorized as heavier. This boat has a precise average ratio between displacement and length!


SA/D (Sail Area Displacement ratio)

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

The SA/D for Johnson 27 with ISO 8666 reference sail is 13.1, with a 135% genua the SA/D is 15.7.

Low High 15% 0 50 100
The SA/D ratio indicates that it is faster than 15% of all similar sailboat designs in light wind.


Over- / underrigged

Low High 50% 0 50 100
The Johnson 27 has more rig than 50% of all similar sailboats, which indicates that this rig is spot on average!


RSP (Relative Speed Performance)

What is Relative Speed Performance?

The Relative Speed Performance for Johnson 27 is 10

Slow Fast 10% 0 50 100
The relative speed performance is 10 which means that a it is faster than 10% 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 21m2 (226 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 20.6 m(67.4 feet)8 mm(5/16 inch)
Jib/genoa halyard20.6 m(67.4 feet)8 mm(5/16 inch)
Spinnaker halyard20.6 m(67.4 feet)8 mm(5/16 inch)
Jib sheet 8.3 m(27.4 feet)10 mm(3/8 inch)
Genoa sheet8.3 m(27.4 feet)10 mm(3/8 inch)
Mainsheet 20.9 m(68.4 feet)10 mm(3/8 inch)
Spinnaker sheet18.3 m(60.2 feet)10 mm(3/8 inch)
Cunningham2.9 m(9.5 feet)8 mm(5/16 inch)
Kickingstrap5.8 m(19.0 feet)8 mm(5/16 inch)
Clew-outhaul5.8 m(19.0 feet)8 mm(5/16 inch)

Boat owner's ideas

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

Do you have changes/improvements you would like to share? Upload a photo and describe what to look for.



Finally

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