Review of Bacchant IV

Bacchant IV
Bacchant IV anno 1972.

Basic specs.

sail specifications
The Bacchant IV is a sailboat designed by the Swedish maritime architect Knud Hielmberg Reimers in the mid sixties. Less than 100 boats have been produced. The Bacchant IV is built by the Swedish yard Västerås Fiberplast.

Looking for a new boat? Find a Bacchant IV or similar boat for sale

The hull is made of fibreglass. Generally, a hull made of fibreglass requires only a minimum of maintenance during the sailing season.

Note: the boat has also been sold to be self-made/-interiored, which means that the quality of each boat may vary.

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 of Bacchant IV anno 1967.

The Bacchant IV 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.

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 most marinas as the draft is just about 1.60 - 1.70 meter (5.25 - 5.55 ft) dependent on the load. See immersion rate below.


Bacchant IV is typically equipped with an inboard engine.

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.

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 Bacchant IV is 1.48, 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 6.8 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 Bacchant IV is about 143 kg/cm, alternatively 804 lbs/inch.
Meaning: if you load 143 kg cargo on the boat then it will sink 1 cm. Alternatively, if you load 804 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 Bacchant IV is 40.6.

Low High 98% 0 50 100
Comparing this ratio with similar sailboats show that it is more comfortable than 98% 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 Bacchant IV is 4.00.

Wide Slim 99% 0 50 100
Compared with other similar sailboats it is slimmer than 99% of all other designs. It seems that the designer has chosen a significantly more speedy hull design. This type of design is also referred to as 'needle'.

Ballast Ratio

What is a Ballast Ratio?

The ballast ratio for Bacchant IV is 43%.

Low High 69% 0 50 100
This ballast ratio shows a righting moment that is higher than 69% 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 Bacchant IV is 368 which categorizes this boat among 'heavy cruisers'.

Heavy Light 10% 0 50 100
10% 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 Bacchant IV with ISO 8666 reference sail is 13.8, with a 135% genua the SA/D is 16.4.

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 58% 0 50 100
The Bacchant IV has more rig than 58% of all similar sailboats, which indicates that the boat is slightly overrigged.

RSP (Relative Speed Performance)

What is Relative Speed Performance?

The Relative Speed Performance for Bacchant IV is 2

Slow Fast 2% 0 50 100
The relative speed performance is 2 which means that a it is faster than 2% of all similar sailboat designs.


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 17m2 (182 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.

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
Mainsail halyard 27.6 m(90.4 feet)12 mm(1/2 inch)
Jib/genoa halyard27.6 m(90.4 feet)12 mm(1/2 inch)
Spinnaker halyard27.6 m(90.4 feet)12 mm(1/2 inch)
Jib sheet 10.9 m(35.9 feet)14 mm(0.55 inch)
Genoa sheet10.9 m(35.9 feet)14 mm(0.55 inch)
Mainsheet 27.3 m(89.6 feet)14 mm(0.55 inch)
Spinnaker sheet24.0 m(78.9 feet)14 mm(0.55 inch)
Cunningham4.2 m(13.9 feet)12 mm(1/2 inch)
Kickingstrap8.5 m(27.9 feet)12 mm(1/2 inch)
Clew-outhaul8.5 m(27.9 feet)12 mm(1/2 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.


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