Review of Mumm 30

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.

The boat can only enter major marinas as the draft is about 2.15 - 2.25 meter (7.05 - 7.35 ft) dependent on the load. See immersion rate below.

The boat is typically equipped with an inboard Yanmar diesel engine at 10.0 hp (7 kW), which gives a max speed about 5.8 knots.

What is Capsize Screening Formula (CSF)?

The capsize screening value for Mumm 30 is 2.41, indicating that this boat would not be accepted to participate in ocean races.

What is Theoretical Maximum Hull Speed?

The theoretical maximal speed of a displacement boat of this length is 7.0 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.

The immersion rate is defined as the weight required to sink the boat a certain level. The immersion rate for Mumm 30 is about 171 kg/cm, alternatively 959 lbs/inch.
Meaning: if you load 171 kg cargo on the boat then it will sink 1 cm. Alternatively, if you load 959 lbs cargo on the boat it will sink 1 inch.

What is Motion Comfort Ratio (MCR)?

The Motion Comfort Ratio for Mumm 30 is 11.4.

Comparing this ratio with similar sailboats show that it is more comfortable than 3% 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 Mumm 30 is 3.11.

Compared with other similar sailboats it is more spacy than 54% 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 Mumm 30 is 47%.

This ballast ratio shows a righting moment that is higher than 82% of all similar sailboat designs. A righting moment (ability to resist heeling) significantly above average.

What is Displacement Length Ratio?

The DL-ratio for Mumm 30 is 96 which categorizes this boat among 'ultra light racers'.

97% 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 Mumm 30 with ISO 8666 reference sail is 29.1, with a 135% genua the SA/D is 33.3.

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

The Mumm 30 has more rig than 99% of all similar sailboats, which indicates that the boat is significantly overrigged.

When buying anti-fouling bottom paint, it's nice to know how much to buy. The surface of the wet bottom is about 33m² (355 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.

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 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.

We are always looking for new photos. If you can contribute with photos for Mumm 30 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.