Review of Karate Mk I

Basic specs.

The Karate Mk I is a sailboat designed by the maritime architect Michel Bigoin together with Jacques Duvergie in the late sixties. The Karate Mk I is built by the French yard Nautiques du Sud-Ouest.

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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. 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 2 cabins, 5 berths and 200.0 liter fresh water capacity.

Rig

The Karate Mk I 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 Karate Mk I 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.

Engine

The Karate Mk I has been equipped with different engine alternatives.

Alternative 1:

Karate Mk I may be equipped with an inboard Volvo Penta engine

Alternative 2:

The boat may be equipped with an inboard Farymann diesel engine

The fuel tank has a capacity of 50.0 liters (13 US gallons, 10 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 Karate Mk I is 1.80, 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 6.6 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 Karate Mk I is about 144 kg/cm, alternatively 807 lbs/inch.
Meaning: if you load 144 kg cargo on the boat then it will sink 1 cm. Alternatively, if you load 807 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 Karate Mk I is 27.9.

Comparing this ratio with similar sailboats show that it is more comfortable than 69% 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 Karate Mk I is 3.37.

Compared with other similar sailboats it is slimmer than 66% of all other designs. It seems that the designer has chosen a slightly more speedy hull design.

Ballast Ratio

What is a Ballast Ratio?

The ballast ratio for Karate Mk I is 38%.

This ballast ratio shows a righting moment that is higher than 34% of all similar sailboat designs. A righting moment (ability to resist heeling) just below average.

D/L (Displacement Length Ratio)

What is Displacement Length Ratio?

The DL-ratio for Karate Mk I is 322 which categorizes this boat among 'medium weight cruisers'.

18% 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)

SA/D (Sail Area Displacement ratio)
Indicates how fast the boat is in light wind:
- Cruising Boats have ratios 10-15
- Cruiser-Racers have ratios 16-20
- Racers have ratios above 20
- High-Performance Racers have ratios above 24
Sail-area/displacement ratio (SA/D ratio): 18.16

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 26m² (279 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

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
Jib sheet	9.9 m	(32.6 feet)	12 mm	(1/2 inch)
Genoa sheet	9.9 m	(32.6 feet)	12 mm	(1/2 inch)
Mainsheet	24.9 m	(81.6 feet)	12 mm	(1/2 inch)
Spinnaker sheet	21.9 m	(71.8 feet)	12 mm	(1/2 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 Karate Mk I 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.