Review of LM 24

LM 24 anno 1979.

Basic specs.

The LM 24 is a motorsailer designed by the Danish maritime architect Palle Mortensen in the late seventies. Several hundred boats have been produced. The LM 24 is built by the Danish yard LM Glasfiber A/S.

Looking for a new boat? Find a LM 24 or similar boat for sale

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 interior is like many other boats made of mahogany.
The boat is equipped with one cabin, 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 LM 24 is equipped with a long keel. A long keel provide a better directional stability than a similar boat with a fin keel; on the other hand, better directional stability means also that the boat is more difficult to handle in a harbour with less space.

The keel is made of iron. Many people prefer lead keel in favour of iron. The main argument is that lead is much heavier than iron and a lead keel can therefore be made smaller which again result in less wet surface, i.e. less drag. In fact iron is quite heavy, just 30% less heavy than lead, so the advantage of a lead keel is often overstated.

The boat can enter even shallow marinas as the draft is just about 1.00 - 1.10 meter (3.28 - 3.58 ft) dependent on the load. See immersion rate below.

Engine

LM 24 is typically equipped with an inboard Volvo Penta MD 7A diesel engine.

The fuel tank has a capacity of 90.0 liters (23 US gallons, 19 imperial gallons).

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 LM 24 is 1.83, 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 6.0 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 LM 24 is about 100 kg/cm, alternatively 562 lbs/inch.
Meaning: if you load 100 kg cargo on the boat then it will sink 1 cm. Alternatively, if you load 562 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 LM 24 is 24.8.

Comparing this ratio with similar sailboats show that it is more comfortable than 95% of all similar sailboat designs. This is a comfort value significantly above average.

L/B (Length Beam Ratio)

What is L/B (Length Beam Ratio)?

The l/b ratio for LM 24 is 2.93.

Compared with other similar sailboats it is more spacy than 50% of all other designs. It seems that the designer has chosen an average hull design.

Ballast Ratio

What is a Ballast Ratio?

The ballast ratio for LM 24 is 40%.

This ballast ratio shows a righting moment that is higher than 54% 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 LM 24 is 306 which categorizes this boat among 'medium weight cruisers'.

12% 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 LM 24 with ISO 8666 reference sail is 12.4, with a 135% genua the SA/D is 14.4.

The SA/D ratio indicates that it is faster than 14% of all similar sailboat designs in light wind.
Don't panic! It is expected that motor sailers has a low SA/D value as this is the natural consequence of the design combining sailing and motor boat characteristics.

Over- / underrigged

The LM 24 has more rig than 42% of all similar sailboats, which indicates that the boat is slightly underrigged.
It is expected that motor sailers are underrigged as this is the natural consequence of combining sailing and motor characteristics.

RSP (Relative Speed Performance)

What is Relative Speed Performance?

The Relative Speed Performance for LM 24 is 1

The relative speed performance is 1 which means that a it is faster than 1% of all similar sailboat designs. As this boat is a motor sailer, it is expected that the performance of a motor sailer for sail alone is lower than a dedicated sailboat.

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 11m² (118 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 masthead 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.

**Guiding dimensions of running rig**
Usage	Length		Diameter
Mainsail halyard	20.9 m	(68.7 feet)	8 mm	(5/16 inch)
Jib/genoa halyard	20.9 m	(68.7 feet)	8 mm	(5/16 inch)
Spinnaker halyard	20.9 m	(68.7 feet)	8 mm	(5/16 inch)
Jib sheet	7.2 m	(23.6 feet)	10 mm	(3/8 inch)
Genoa sheet	7.2 m	(23.6 feet)	10 mm	(3/8 inch)
Mainsheet	18.0 m	(59.1 feet)	10 mm	(3/8 inch)
Spinnaker sheet	15.8 m	(52.0 feet)	10 mm	(3/8 inch)
Cunningham	3.2 m	(10.5 feet)	8 mm	(5/16 inch)
Kickingstrap	6.4 m	(21.0 feet)	8 mm	(5/16 inch)
Clew-outhaul	6.4 m	(21.0 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 LM 24 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.