Review of Prospect 900

Prospect 900 anno 1977.

Basic specs.

The Prospect 900 is a sailboat designed by the Dutch maritime architect E. G. van de Stadt. The Prospect 900 is built by the British yard Rydgeway Marine Ltd..

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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 5 berths, a galley, 136.0 liter fresh water capacity and toilet facility.

Rig

The Prospect 900 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 Prospect 900 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 enter most marinas as the draft is just about 1.50 - 1.60 meter (4.92 - 5.22 ft) dependent on the load. See immersion rate below.

Engine

Prospect 900 may be equipped with an inboard Volvo Penta MD5A diesel engine at 7 hp (5 kW). Calculated max speed is about 3.5 knots

The transmission is a saildrive.

The fuel tank has a capacity of 46.0 liters (12 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 Prospect 900 is 1.90, 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 6.4 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 Prospect 900 is about 128 kg/cm, alternatively 719 lbs/inch.
Meaning: if you load 128 kg cargo on the boat then it will sink 1 cm. Alternatively, if you load 719 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 Prospect 900 is 24.0.

Comparing this ratio with similar sailboats show that it is more comfortable than 62% 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 Prospect 900 is 3.11.

Compared with other similar sailboats it is slimmer than 54% 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 Prospect 900 is 52%.

This ballast ratio shows a righting moment that is higher than 95% of all similar sailboat designs. A righting moment (ability to resist heeling) significantly above average.

D/L (Displacement Length Ratio)

What is Displacement Length Ratio?

The DL-ratio for Prospect 900 is 286 which categorizes this boat among 'medium weight cruisers'.

34% 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.

RSP (Relative Speed Performance)

What is Relative Speed Performance?

The Relative Speed Performance for Prospect 900 is 42

The relative speed performance is 42 which means that a it is faster than 42% 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 22m² (236 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	8.7 m	(28.5 feet)	10 mm	(3/8 inch)
Genoa sheet	8.7 m	(28.5 feet)	10 mm	(3/8 inch)
Mainsheet	21.8 m	(71.4 feet)	10 mm	(3/8 inch)
Spinnaker sheet	19.1 m	(62.8 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 Prospect 900 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.