Review of Bonin 34

Basic specs.

The Bonin 34 aka Bonin 36 is a sailboat designed by the Italian maritime architect Maurizio Cossutti together with Bonin also from Italy in the early 2000.

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Hull

The hull is made of fibreglass. Generally, a hull made of fibreglass requires only a minimum of maintenance during the sailing season.
The hull is a double hull which improves the indoor climate. Especially when the water is colder than the air in the cabin, then the double hull insulates against cold water and reduce the condense water in the cabin.

Interior

The boat is equipped with 7 berths and 140.0 liter fresh water capacity.

Rig

The Bonin 34 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.

Keel

Fin keel

The Bonin 34 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.

The boat can only enter major marinas as the draft is about 1.80 - 1.90 meter (5.91 - 6.21 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 Bonin 34 is 2.20, indicating that this boat would not be accepted to participate in ocean races.

EU classification

Bonin 34 holds a CE certification:

The boat is by European Union certified as Class B. OFFSHORE:

Designed for offshore voyages where conditions up to, and including, wind force 8 (Beaufort scale) and significant wave heights up to, and including, 4 m may be experienced.

Theoretical Maximum Hull Speed

What is Theoretical Maximum Hull Speed?

The theoretical maximal speed of a displacement boat of this length is 7.4 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 Bonin 34 is about 226 kg/cm, alternatively 1269 lbs/inch.
Meaning: if you load 226 kg cargo on the boat then it will sink 1 cm. Alternatively, if you load 1269 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 Bonin 34 is 18.1.

Comparing this ratio with similar sailboats show that it is more comfortable than 15% 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 Bonin 34 is 2.77.

Compared with other similar sailboats it is more spacy than 85% of all other designs. It seems that the designer has chosen a significantly more spacy hull design.

D/L (Displacement Length Ratio)

What is Displacement Length Ratio?

The DL-ratio for Bonin 34 is 150 which categorizes this boat among 'ultra light racers'.

86% 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 Bonin 34 with ISO 8666 reference sail is 18.3, with a 135% genua the SA/D is 21.6.

The SA/D ratio indicates that it is faster than 73% of all similar sailboat designs in light wind.

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 40m² (430 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.

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	28.8 m	(94.5 feet)	10 mm	(3/8 inch)
Jib/genoa halyard	28.8 m	(94.5 feet)	10 mm	(3/8 inch)
Spinnaker halyard	28.8 m	(94.5 feet)	10 mm	(3/8 inch)
Jib sheet	10.0 m	(32.8 feet)	12 mm	(1/2 inch)
Genoa sheet	10.0 m	(32.8 feet)	12 mm	(1/2 inch)
Mainsheet	25.0 m	(81.9 feet)	12 mm	(1/2 inch)
Spinnaker sheet	22.0 m	(72.1 feet)	12 mm	(1/2 inch)
Cunningham	4.2 m	(13.8 feet)	10 mm	(3/8 inch)
Kickingstrap	8.4 m	(27.6 feet)	10 mm	(3/8 inch)
Clew-outhaul	8.4 m	(27.6 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 Bonin 34 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.