Review of Neptun 25

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.

The Neptun 25 has been built with different keel alternatives.

Fin keel

The Neptun 25 is equipped with a fin keel. The fin keel is the most common keel and provides splendid manoeuvrability. The downside is that it has less directional stability than a long keel.

The boat can enter even shallow marinas as the draft is just about 1.25 - 1.35 meter (4.10 - 4.40 ft) dependent on the load. See immersion rate below.

DaggerBoard aka Sword

The Neptun 25 is equipped with a daggerboard keel. A daggerboard is a lifting keel that can be lowered and raised, allowing the boat to enter shallow waters as well.

The boat can enter even shallow marinas as the draft is just about 0.65 - 0.75 meter (2.13 - 2.43 ft) dependent on the load. See immersion rate below.

What is Capsize Screening Formula (CSF)?

The capsize screening value for Neptun 25 is 2.34, indicating that this boat would not be accepted to participate in ocean races.

What is Theoretical Maximum Hull Speed?

The theoretical maximal speed of a displacement boat of this length is 6.0 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.

The immersion rate is defined as the weight required to sink the boat a certain level. The immersion rate for Neptun 25 is about 103 kg/cm, alternatively 581 lbs/inch.
Meaning: if you load 103 kg cargo on the boat then it will sink 1 cm. Alternatively, if you load 581 lbs cargo on the boat it will sink 1 inch.

What is Motion Comfort Ratio (MCR)?

The Motion Comfort Ratio for Neptun 25 is 11.9.

Comparing this ratio with similar sailboats show that it is more comfortable than 15% of all similar sailboat designs. This is a comfort value significantly below average.

What is L/B (Length Beam Ratio)?

The l/b ratio for Neptun 25 is 3.00.

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.

What is Displacement Length Ratio?

The DL-ratio for Neptun 25 is 146 which categorizes this boat among 'ultra light racers'.

82% of all similar sailboat designs are categorized as heavier. A light displacement requires less sailarea and has higher accellerations.

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.

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.

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.

We are always looking for new photos. If you can contribute with photos for Neptun 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.

[Ref 1]: ISO 8666 Small craft — Principal data.
[Ref 3]: ISO 12215-5 Small craft — Hull construction and scantlings.