Review of Neptune 99

The hull is made of fibreglass. A hull made of fibreglass requires only a minimum of maintenance during the sailing season.
Some boats have a hull made of Fibreglass.

The deck is a sandwich construction which improves the indoor climate. Especially when the water is colder than the air in the cabin, then the double hull insulates against cold water and reduce the condense water in the cabin. The core material in the sandwich construction is balsa.

The boat is equipped with 170 liters (44 US gallons, 37 imperial gallons) fresh water capacity and toilet facility.

Drop keel

The Neptune 99 is built with a drop keel. A drop keel is a lifting keel that can be lowered and raised vertically, allowing the boat to enter shallow 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 enter even shallow marinas as the draft is just about 1.00 - 1.10 meter (3.28 - 3.58 ft) dependent on the load. See immersion rate below.

The fuel tank has a capacity of 65 liters (17 US gallons, 14 imperial gallons).

Neptune 99 may be equipped with an inboard Nanni N3 diesel engine at 21 hp (15 kW). Cruise speed is 6.0 knots.

What is Capsize Screening Formula (CSF)?

The capsize screening value for Neptune 99 is 2.08, 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 7.1 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 Neptune 99 is about 203 kg/cm, alternatively 1138 lbs/inch.
Meaning: if you load 203 kg cargo on the boat then it will sink 1 cm. Alternatively, if you load 1138 lbs cargo on the boat it will sink 1 inch.

What is Motion Comfort Ratio (MCR)?

The Motion Comfort Ratio for Neptune 99 is 21.9.

Comparing this ratio with similar sailboats show that it is more comfortable than 34% of all similar sailboat designs. This comfort value is just below average.

What is L/B (Length Beam Ratio)?

The l/b ratio for Neptune 99 is 2.83.

Compared with other similar sailboats it is more spacy than 82% of all other designs. It seems that the designer has chosen a significantly more spacy hull design.

What is a Ballast Ratio?

The ballast ratio for Neptune 99 is 40%.

This ballast ratio is higher than 46% of all similar sailboat designs. Since the ballast ratio and the righting moment (i.e. better ability to resist heeling) is strongly correlated, a ballast ratio just below average indicates an ability to resist heeling below average.

What is Displacement Length Ratio?

The DL-ratio for Neptune 99 is 219 which categorizes this boat among 'moderate racers'.

66% of all similar sailboat designs are categorized as heavier. A light displacement requires less sailarea and has higher accellerations.

As balsa wood is used as sandwich core material special care must be taken in relation to work that require penetration of the sandwich construction in order to to prevent water to get in contact with the balsa wood. Otherwise the balsa wood will eventually rotten and be expensive/impossible to repair.

When buying anti-fouling bottom paint, it's nice to know how much to buy. The surface of the wet bottom is about 35m² (376 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.

Keels with moving parts need to be inspected and maintained on a regular basis according to advice given in owner's manual. Manufacturers usually advise which maintenance work can be done by the owner and which work should be carried out by a suitably experienced boatyard.

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 Neptune 99 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.