Review of J/108

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 boat is equipped with 4 berths and 150.0 liter fresh water capacity.

The J/108 is equipped with a fractional rig. A fractional rig has smaller headsails which make tacking easier, which is an advantage for cruisers and racers, of course. The downside is that having the wind from behind often requires a gennaker or a spinnaker for optimal speed.

CentreBoard

The J/108 is equipped with a centreboard keel. A centreboard keel is a pivoting lifting keel, allowing to sail both coastal and inland waters.

The boat can enter even shallow marinas as the draft is just about 1.22 - 1.32 meter (4.00 - 4.30 ft) dependent on the load. See immersion rate below.

What is Capsize Screening Formula (CSF)?

The capsize screening value for J/108 is 2.05, indicating that this boat would not be accepted to participate in ocean races.

J/108 holds a CE certification:

The boat is by European Union certified as Class A. OCEAN:

What is Theoretical Maximum Hull Speed?

The theoretical maximal speed of a displacement boat of this length is 7.4 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 J/108 is about 218 kg/cm, alternatively 1224 lbs/inch.
Meaning: if you load 218 kg cargo on the boat then it will sink 1 cm. Alternatively, if you load 1224 lbs cargo on the boat it will sink 1 inch.

What is Motion Comfort Ratio (MCR)?

The Motion Comfort Ratio for J/108 is 21.2.

Comparing this ratio with similar sailboats show that it is more comfortable than 21% 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 J/108 is 3.06.

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 a Ballast Ratio?

The ballast ratio for J/108 is 39%.

This ballast ratio shows a righting moment that is higher than 46% of all similar sailboat designs. A righting moment (ability to resist heeling) just below average.

What is Displacement Length Ratio?

The DL-ratio for J/108 is 179 which categorizes this boat among 'light racers'.

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

What is SA/D (Sail Area Displacement ratio)?

The SA/D for J/108 with ISO 8666 reference sail is 19.0, with a 135% genua the SA/D is 22.3.

The SA/D ratio indicates that it is faster than 79% of all similar sailboat designs in light wind.

The J/108 has more rig than 66% of all similar sailboats, which indicates that the boat is slightly overrigged.

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 39m² (419 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.

Dimensions of sail for fractional rig.

Are your sails worn out? You might find your next sail here: Sails for Sale

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 J/108 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.