Review of Alden 48

Alden 48
Alden 48. At Newport, RI 2015

Basic specs.

sail specifications
The Alden 48 is a large sailboat designed by the American maritime architect Niels C. Helleberg in the late eighties.

Looking for a new boat? Find a Alden 48 or similar boat for sale


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


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.


The Alden 48 is equipped with a centerboard keel. A centerboard keel is a pivoting lifting keel, allowing to sail both coastal and inland waters.

The boat can enter most marinas as the draft is just about 1.62 - 1.72 meter (5.31 - 5.61 ft) dependent on the load. See immersion rate below.

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 Alden 48 is 1.70, indicating that this boat could - if evaluated by this formula alone - be accepted to participate in ocean races.

Theoretical Maximum Hull Speed

What is Theoretical Maximum Hull Speed?

The theoretical maximal speed of a displacement boat of this length is 8.2 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 Alden 48 is about 311 kg/cm, alternatively 1742 lbs/inch.
Meaning: if you load 311 kg cargo on the boat then it will sink 1 cm. Alternatively, if you load 1742 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.

Motion Comfort Ratio

What is Motion Comfort Ratio (MCR)?

The Motion Comfort Ratio for Alden 48 is 37.8.

Low High 66% 0 50 100
Comparing this ratio with similar sailboats show that it is more comfortable than 66% of all similar sailboat designs. This comfort value is just above average.

L/B (Length Beam Ratio)

What is L/B (Length Beam Ratio)?

The l/b ratio for Alden 48 is 3.62.

Wide Slim 69% 0 50 100
Compared with other similar sailboats it is slimmer than 69% of all other designs. It seems that the designer has chosen a slightly more speedy hull design.

Ballast Ratio

What is a Ballast Ratio?

The ballast ratio for Alden 48 is 40%.

Low High 73% 0 50 100
This ballast ratio shows a righting moment that is higher than 73% of all similar sailboat designs. A righting moment (ability to resist heeling) just above average.

D/L (Displacement Length Ratio)

What is Displacement Length Ratio?

The DL-ratio for Alden 48 is 280 which categorizes this boat among 'medium weight cruisers'.

Heavy Light 31% 0 50 100
31% of all similar sailboat designs are categorized as heavier. A heavy displacement combined with smaller water plane area has lower acceleration and is more comfortable.

SA/D (Sail Area Displacement ratio)

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

The SA/D for Alden 48 with ISO 8666 reference sail is 17.1, with a 135% genua the SA/D is 20.3.

Low High 21% 0 50 100
The SA/D ratio indicates that it is faster than 21% of all similar sailboat designs in light wind.

Over- / underrigged


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 61m2 (656 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 masthead 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
Mainsail halyard 42.1 m(138.0 feet)14 mm(0.55 inch)
Jib/genoa halyard42.1 m(138.0 feet)14 mm(0.55 inch)
Spinnaker halyard42.1 m(138.0 feet)14 mm(0.55 inch)
Jib sheet 14.9 m(48.8 feet)16 mm(5/8 inch)
Genoa sheet14.9 m(48.8 feet)16 mm(5/8 inch)
Mainsheet 37.1 m(121.9 feet)16 mm(5/8 inch)
Spinnaker sheet32.7 m(107.3 feet)16 mm(5/8 inch)
Cunningham5.7 m(18.7 feet)14 mm(0.55 inch)
Kickingstrap11.4 m(37.5 feet)14 mm(0.55 inch)
Clew-outhaul11.4 m(37.5 feet)14 mm(0.55 inch)

Boat owner's ideas

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.


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