Udkik.dk

Review of Nauticat 25


Nauticat 25
Nauticat 25.

Basic specs.

sail specifications
The Nauticat 25 is a small motorsailer designed in the early seventies. Less than 100 boats have been produced. The Nauticat 25 is built by the Finnish yard Siltala Yachts Oy.

Looking for a new boat? Find a Nauticat 25 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
The interior is like many other boats made of mahogany.
The boat is equipped with one cabin, 4 berths, a galley and toilet facility.

Rig
Rig
Rig of Nauticat 25 anno 1979. Naam boot Sindbad

Keel

The Nauticat 25 is equipped with 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 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 enter even shallow marinas as the draft is just about 0.90 - 1.00 meter (2.95 - 3.25 ft) dependent on the load. See immersion rate below.


Engine

Nauticat 25 is typically equipped with an inboard Yanmar diesel engine at 12.0 hp (8 kW), which gives a max speed about 4.8 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 65.0 liters (17 US gallons, 14 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 Nauticat 25 is 1.70, 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 6.3 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 Nauticat 25 is about 107 kg/cm, alternatively 603 lbs/inch.
Meaning: if you load 107 kg cargo on the boat then it will sink 1 cm. Alternatively, if you load 603 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 Nauticat 25 is 27.6.

Low High 96% 0 50 100
Comparing this ratio with similar sailboats show that it is more comfortable than 96% 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 Nauticat 25 is 3.12.

Wide Slim 69% 0 50 100
Compared with other similar sailboats it is slimmer than 69% 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 Nauticat 25 is 18%.

Low High 1% 0 50 100
This ballast ratio shows a righting moment that is higher than 1% 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 Nauticat 25 is 268 which categorizes this boat among 'light crusers & offshore racers'.

Heavy Light 27% 0 50 100
27% 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.


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 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.


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
UsageLengthDiameter
Jib sheet 7.5 m(24.6 feet)10 mm(3/8 inch)
Genoa sheet7.5 m(24.6 feet)10 mm(3/8 inch)
Mainsheet 18.8 m(61.5 feet)10 mm(3/8 inch)
Spinnaker sheet16.5 m(54.1 feet)10 mm(3/8 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 Nauticat 25 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