Review of Bianca 27

Bianca 27 anno 1969.

Basic specs.

The Bianca 27 is a sailboat designed by the Danish maritime architect Svend Aage Leth Christensen in the mid sixties. Several hundred boats have been produced. The Bianca 27 is built by the Danish yard Bianca.

Looking for a new boat? Find a Bianca 27 or similar boat for sale

Hull

The hull 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

Interior of Bianca 27 anno 1974. Salongen på vår Bianca 27 som vi haft sedan ny.

The interior is like many other boats made of mahogany.
The boat is equipped with 4 berths, a galley and toilet facility.
The headroom is above average

Rig

Rig of Bianca 27.

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 Bianca 27 has been built with more than one type of keel.

One option is a long keel. A long keel provide a better directional stability than a similar boat with a fin keel; on the other hand, better directional stability means also that the boat is more difficult to handle in a harbour with less space.

Another option is 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.

The keel is made of iron. Many people prefer lead keel in favour of iron. The main argument is that lead is much heavier than iron and a lead keel can therefore be made smaller which again result in less wet surface, i.e. less drag. In fact iron is quite heavy, just 30% less heavy than lead, so the advantage of a lead keel is often overstated. As the surface of a fin type keel is just a fraction of the total wet surface, the difference between an iron keel and a lead keel can in reality be ignored for cruising yachts.

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

Bianca 27 is typically equipped with an inboard Bukh DV10 diesel engine at 10.0 hp (7 kW), which gives a max speed about 4.0 knots.

The transmission is a shaft drive. A shaft drive will in the long run require less maintenence than other types of drive e.g. a sail drive.

The fuel tank has a capacity of 40.0 liters (10 US gallons, 8 imperial gallons).

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 Bianca 27 is 1.66, 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 6.0 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 Bianca 27 is about 101 kg/cm, alternatively 567 lbs/inch.
Meaning: if you load 101 kg cargo on the boat then it will sink 1 cm. Alternatively, if you load 567 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 Bianca 27 is 30.8.

Comparing this ratio with similar sailboats show that it is more comfortable than 95% of all similar sailboat designs. This is a comfort value significantly above average.

L/B (Length Beam Ratio)

What is L/B (Length Beam Ratio)?

The l/b ratio for Bianca 27 is 3.38.

Compared with other similar sailboats it is slimmer than 86% 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 Bianca 27 is 45%.

This ballast ratio shows a righting moment that is higher than 73% of all similar sailboat designs. A righting moment (ability to resist heeling) just above average.

D/L (Displacement Length Ratio)

What is Displacement Length Ratio?

The DL-ratio for Bianca 27 is 380 which categorizes this boat among 'heavy cruisers'.

5% of all similar sailboat designs are categorized as heavier. A heavy displacement combined with smaller water plane area has lower acceleration and is more comfortable.

SA/D (Sail Area Displacement ratio)

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

The SA/D for Bianca 27 with ISO 8666 reference sail is 14.2, with a 135% genua the SA/D is 16.8.

The SA/D ratio indicates that it is faster than 27% of all similar sailboat designs in light wind.

Over- / underrigged

The Bianca 27 has more rig than 38% of all similar sailboats, which indicates that the boat is slightly underrigged.

RSP (Relative Speed Performance)

What is Relative Speed Performance?

The Relative Speed Performance for Bianca 27 is 8

The relative speed performance is 8 which means that a it is faster than 8% 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 18m² (193 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	22.9 m	(75.2 feet)	8 mm	(5/16 inch)
Jib/genoa halyard	22.9 m	(75.2 feet)	8 mm	(5/16 inch)
Spinnaker halyard	22.9 m	(75.2 feet)	8 mm	(5/16 inch)
Jib sheet	8.2 m	(27.1 feet)	10 mm	(3/8 inch)
Genoa sheet	8.2 m	(27.1 feet)	10 mm	(3/8 inch)
Mainsheet	20.6 m	(67.7 feet)	10 mm	(3/8 inch)
Spinnaker sheet	18.2 m	(59.5 feet)	10 mm	(3/8 inch)
Cunningham	3.4 m	(11.0 feet)	8 mm	(5/16 inch)
Kickingstrap	6.7 m	(22.0 feet)	8 mm	(5/16 inch)
Clew-outhaul	6.7 m	(22.0 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 Bianca 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

[Ref 1]: ISO 8666 Small craft — Principal data.
[Ref 3]: ISO 12215-5 Small craft — Hull construction and scantlings.