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Review of Clipper Marine 21


Clipper Marine 21
Clipper Marine 21 anno 1971.

Basic specs.

sail specifications
The Clipper Marine 21 also known as Clipper MK 21 is a small sailboat designed by the British maritime architect William Ion Belton Crealock in the early seventies. The Clipper Marine 21 is built by the American yard Clipper Marine, Corp..

Looking for a new boat? Find a Clipper Marine 21 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.


Cockpit
Cockpit
Cockpit of Clipper Marine 21 anno 1971.
Rig

The Clipper Marine 21 is equipped with a fractional rig. A fractional rig has smaller headsails which make tacking easier, which is an advantage for cruisers and racers, of course. The downside is that having the wind from behind often requires a gennaker or a spinnaker for optimal speed.


Keel

Swing keel

The Clipper Marine 21 is equipped with a swing keel. A swing keel is a pivoting lifting keel, allowing to sail both coastal and inland waters.

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.

The boat can sail close to the beach as the draft is just 0.27 - 0.37 meter (0.89 - 1.19 ft) dependent of the load. See immersion rate below.


Engine

An outboard motor is often used on this boat. In that case the boat will typically require a power of 2 - 3 hp, alternatively 33 - 40 lbs thrust if you prefer an electrical motor. Electric outboards are becoming popular for sailboat owners who want clean instant power with less noise and no exhaust fumes.


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 Clipper Marine 21 is 2.47, indicating that this boat would not 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 5.7 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 Clipper Marine 21 is about 81 kg/cm, alternatively 454 lbs/inch.
Meaning: if you load 81 kg cargo on the boat then it will sink 1 cm. Alternatively, if you load 454 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 Clipper Marine 21 is 9.5.

Low High 21% 0 50 100
Comparing this ratio with similar sailboats show that it is more comfortable than 21% 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 Clipper Marine 21 is 2.87.

Wide Slim 62% 0 50 100
Compared with other similar sailboats it is slimmer than 62% 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 Clipper Marine 21 is 27%.

Low High 15% 0 50 100
This ballast ratio shows a righting moment that is higher than 15% of all similar sailboat designs. A righting moment (ability to resist heeling) significantly below average.


D/L (Displacement Length Ratio)

What is Displacement Length Ratio?

The DL-ratio for Clipper Marine 21 is 130 which categorizes this boat among 'ultra light racers'.

Heavy Light 79% 0 50 100
79% 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 Clipper Marine 21 with ISO 8666 reference sail is 23.4, with a 135% genua the SA/D is 27.9.

Low High 88% 0 50 100
The SA/D ratio indicates that it is faster than 88% of all similar sailboat designs in light wind.


Over- / underrigged

Low High 100% 0 50 100
The Clipper Marine 21 has more rig than 100% of all similar sailboats, which indicates that the boat is significantly overrigged.


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 14m2 (150 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 fractional rig.

mainsail specifications headsail 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
UsageLengthDiameter
Mainsail halyard 17.5 m(57.5 feet)8 mm(5/16 inch)
Jib/genoa halyard17.5 m(57.5 feet)8 mm(5/16 inch)
Spinnaker halyard17.5 m(57.5 feet)8 mm(5/16 inch)
Jib sheet 6.4 m(21.0 feet)10 mm(3/8 inch)
Genoa sheet6.4 m(21.0 feet)10 mm(3/8 inch)
Mainsheet 16.0 m(52.5 feet)10 mm(3/8 inch)
Spinnaker sheet14.1 m(46.2 feet)10 mm(3/8 inch)
Cunningham2.7 m(8.8 feet)8 mm(5/16 inch)
Kickingstrap5.4 m(17.6 feet)8 mm(5/16 inch)
Clew-outhaul5.4 m(17.6 feet)8 mm(5/16 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 Clipper Marine 21 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