Review of Seal 28

Seal 28 anno 1977.

Basic specs.

The Seal 28 is a sailboat designed by the British maritime architect Angus S. Primrose in the mid seventies.

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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.

Interior

The boat is equipped with 3 cabins, 6 berths, a galley and toilet facility.

Rig

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.

Keel

The boat can enter even shallow marinas as the draft is just about 0.75 - 0.85 meter (2.46 - 2.76 ft) dependent on the load. See immersion rate below.

Engine

Seal 28 is typically equipped with an inboard Bukh DV20 diesel engine at 20.0 hp (14 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.

Stability and Safety

What is Capsize Screening Formula (CSF)?

The capsize screening value for Seal 28 is 2.04, indicating that this boat would not be accepted to participate in ocean races.

Immersion rate

The immersion rate is defined as the weight required to sink the boat a certain level. The immersion rate for Seal 28 is about 170 kg/cm, alternatively 952 lbs/inch.
Meaning: if you load 170 kg cargo on the boat then it will sink 1 cm. Alternatively, if you load 952 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 Seal 28 is 2.82.

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 Seal 28 is 40%.

This ballast ratio shows a righting moment that is higher than 50% of all similar sailboat designs. This righting moment (ability to resist heeling) is spot on average!

SA/D (Sail Area Displacement ratio)

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): 12.21

Maintenance

Rig

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**
Usage	Length		Diameter
Jib sheet	8.5 m	(27.8 feet)	10 mm	(3/8 inch)
Genoa sheet	8.5 m	(27.8 feet)	10 mm	(3/8 inch)
Mainsheet	21.2 m	(69.4 feet)	10 mm	(3/8 inch)
Spinnaker sheet	18.6 m	(61.1 feet)	10 mm	(3/8 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 Seal 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

[Ref 1]: ISO 8666 Small craft — Principal data.
[Ref 3]: ISO 12215-5 Small craft — Hull construction and scantlings.