Review of Onyx 38

The hull is made of fibreglass. Generally, a hull made of fibreglass requires only a minimum of maintenance during the sailing season.

The hull 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 interior is like nearly all boats made of wood.
The boat is equipped with one cabin and 5-6 berths.

Note: the boat has also been sold to be self-made/-interiored, which means that the quality of each boat may vary.

Fin keel

The Onyx 38 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 keel is made of lead. Compared with iron, lead has the advantage of being 44% heavier, which allows a smaller keel and hence less water resistance and higher speed.

Onyx 38 can enter most marinas as the draft is just about 1.70 - 1.80 meter (5.58 - 5.88 ft) dependent on the load. See immersion rate below.

What is Capsize Screening Formula (CSF)?

The capsize screening value for Onyx 38 is 1.71, indicating that this boat could - if evaluated by this formula alone - 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 7.9 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 Onyx 38 is about 192 kg/cm, alternatively 1075 lbs/inch.
Meaning: if you load 192 kg cargo on the boat then it will sink 1 cm. Alternatively, if you load 1075 lbs cargo on the boat it will sink 1 inch.

What is Motion Comfort Ratio (MCR)?

The Motion Comfort Ratio for Onyx 38 is 21.5.

What is L/B (Length Beam Ratio)?

The l/b ratio for Onyx 38 is 4.29.

What is a Ballast Ratio?

The ballast ratio for Onyx 38 is 49%.

What is Displacement Length Ratio?

The DL-ratio for Onyx 38 is 101 which categorizes this boat among 'ultra light racers'.

What is Relative Speed Performance?

The Relative Speed Performance for Onyx 38 is 76

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.

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 Onyx 38 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.