Review of Neptun 20

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 headroom is above average

The boat 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.

The boat can enter even shallow marinas as the draft is just about 0.50 - 0.60 meter (1.64 - 1.94 ft) dependent on the load. See immersion rate below.

What is Capsize Screening Formula (CSF)?

The capsize screening value for Neptun 20 is 2.55, 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 5.5 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 20 is about 79 kg/cm, alternatively 445 lbs/inch.
Meaning: if you load 79 kg cargo on the boat then it will sink 1 cm. Alternatively, if you load 445 lbs cargo on the boat it will sink 1 inch.

What is Motion Comfort Ratio (MCR)?

The Motion Comfort Ratio for Neptun 20 is 10.2.

Comparing this ratio with similar sailboats show that it is more comfortable than 31% of all similar sailboat designs. This comfort value is just below average.

What is L/B (Length Beam Ratio)?

The l/b ratio for Neptun 20 is 2.55.

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

What is Displacement Length Ratio?

The DL-ratio for Neptun 20 is 173 which categorizes this boat among 'light racers'.

54% 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)
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): 24.78

When buying anti-fouling bottom paint, it's nice to know how much to buy. The surface of the wet bottom is about 13m² (139 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 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.

We are always looking for new photos. If you can contribute with photos for Neptun 20 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.