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Review of J/28


Basic specs.

sail specifications
The J/28 is a sailboat designed by the maritime architect Rodney S. Johnstone in the mid eighties.

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Hull
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.

Rig
The boat 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 genaker or a spinnaker for optimal speed.

Keel

The J/28 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 most marinas as the draft is just about 1.52 - 1.62 meter (4.99 - 5.29 ft) dependent on the load. See immersion rate below.


Engine

The boat is typically equipped with an inboard Yanmar 2GM diesel engine at 18.0 hp (13 kW).


Sailing characteristics

This section covers widely used rules of thumb to describe the sailing characteristics. Please note that even though the calculations are correct, the interpretation of the results might not be valid for extreme boats.

Theoretical Maximum Hull Speed

What is Theoretical Maximum Hull Speed?

The theoretical maximal speed of a displacement boat of this length is 6.6 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.


Immersion rate

The immersion rate is defined as the weight required to sink the boat a certain level. The immersion rate for J/28 is about 149 kg/cm, alternatively 837 lbs/inch.
Meaning: if you load 149 kg cargo on the boat then it will sink 1 cm. Alternatively, if you load 837 lbs cargo on the boat it will sink 1 inch.


Sailing statistics

This section is statistical comparison with similar boats of the same category. The basis of the following statistical computations is our unique database with more than 26,000 different boat types and 350,000 data points.

L/B (Length Beam Ratio)

What is L/B (Length Beam Ratio)?

The l/b ratio for J/28 is 2.84.

Slim Wide 76% 0 50 100
Compared with other similar sailboats it is more spacy than 76% of all other designs. It seems that the designer has chosen a significantly more spacy hull design.


Ballast Ratio

What is a Ballast Ratio?

The ballast ratio for J/28 is 38%.

Low High 38% 0 50 100
This ballast ratio shows a righting moment that is higher than 38% of all similar sailboat designs. A righting moment (ability to resist heeling) just below average.


Over- / underrigged

Low High 73% 0 50 100
The J/28 has more rig than 73% of all similar sailboats, which indicates that the boat is slightly overrigged.


Maintenance

Bottom Paint

When buying anti-fouling bottom paint, it's nice to know how much to buy. The surface of the wet bottom is about 25m2 (269 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.


Rig

Dimensions of sail for fractional rig.

mainsail specifications headsail specifications

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.



Guiding dimensions of running rig
UsageLengthDiameter
Mainsail halyard 28.7 m(94.2 feet)8 mm(5/16 inch)
Jib/genoa halyard28.7 m(94.2 feet)8 mm(5/16 inch)
Spinnaker halyard28.7 m(94.2 feet)8 mm(5/16 inch)
Jib sheet 8.7 m(28.4 feet)10 mm(3/8 inch)
Genoa sheet8.7 m(28.4 feet)10 mm(3/8 inch)
Mainsheet 21.6 m(71.0 feet)10 mm(3/8 inch)
Spinnaker sheet19.1 m(62.5 feet)10 mm(3/8 inch)
Cunningham4.0 m(13.0 feet)8 mm(5/16 inch)
Kickingstrap7.9 m(26.0 feet)8 mm(5/16 inch)
Clew-outhaul7.9 m(26.0 feet)8 mm(5/16 inch)

Boat owner's ideas

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.



Finally

We are always looking for new photos. If you can contribute with photos for J/28 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.



References