Review of Johnson 27

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 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.

The Johnson 27 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.

Fin 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 full 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.

The boat may be equipped with an inboard Yanmar 12 diesel engine at 12 hp (8 kW). Calculated max speed is about 4.8 knots

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.

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.

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.

What is Motion Comfort Ratio (MCR)?

The Motion Comfort Ratio for Johnson 27 is 22.0.

What is L/B (Length Beam Ratio)?

The l/b ratio for Johnson 27 is 3.05.

What is Displacement Length Ratio?

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

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.

What is Relative Speed Performance?

The Relative Speed Performance for Johnson 27 is 10

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.

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.

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.

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.