Review of Finngulf 391 DH

Basic specs.

The Finngulf 391 DH is a large motorsailer designed by the Swedish maritime architect Håkan Södergren in the late nineties. Only a few boats have been built. The Finngulf 391 DH is built by the Finnish yard Finngulf Yachts.

A deck house saloon version of the classic 391.

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Hull

Both the hull and the deck is made of fibreglass. A hull made of fibreglass requires only a minimum of maintenance during the sailing season.

Both the hull and the deck is a sandwich construction which improves the indoor climate. Especially when the water is colder than the air in the cabin, then the double hull insulates against cold water and reduce the condense water in the cabin.

Interior

The boat is equipped with 3 cabins, 6-7 berths, 100 liters (26 US gallons, 21 imperial gallons) fresh water capacity and toilet facility.

Rig

The Finngulf 391 DH is built with a fractional rig. The sail area for the mailsail + jib is 69.3 m² (745.7 ft²). 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 gennaker or a spinnaker for optimal speed.

Keel

Fin keel

The Finngulf 391 DH is built with a fin keel. A boat with a fin keel is more manoeuvrable but has less directional stability than a similar boat with a full keel.

The keel is made of lead. Compared with iron, lead has the advantage of being 44% heavier, which allows a smaller keel and hence less water resistance and higher speed.

The boat can only enter major marinas as the draft is about 1.95 - 2.05 meter (6.40 - 6.70 ft) dependent on the load. See immersion rate below.

Engine

The fuel tank, which is made of stainless steel, has a capacity of 100 liters (26 US gallons, 21 imperial gallons).

Finngulf 391 DH may be equipped with an inboard Volvo Penta diesel engine

The transmission is a saildrive.

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 Finngulf 391 DH is 1.88, 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 7.4 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 Finngulf 391 DH is about 218 kg/cm, alternatively 1221 lbs/inch.
Meaning: if you load 218 kg cargo on the boat then it will sink 1 cm. Alternatively, if you load 1221 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 Finngulf 391 DH is 26.7.

Comparing this ratio with similar sailboats show that it is more comfortable than 38% of all similar sailboat designs. This comfort value is just below average.

L/B (Length Beam Ratio)

What is L/B (Length Beam Ratio)?

The l/b ratio for Finngulf 391 DH is 3.38.

Compared with other similar sailboats it is slimmer than 58% 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 Finngulf 391 DH 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 Finngulf 391 DH is 243 which categorizes this boat among 'light crusers & offshore racers'.

54% of all similar sailboat designs are categorized as heavier. A light displacement requires less sailarea and has higher accellerations.

SA/D (Sail Area Displacement ratio)

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

The SA/D for Finngulf 391 DH with ISO 8666 reference sail is 19.6, with a 135% genua the SA/D is 22.7.

The SA/D ratio indicates that it is faster than 73% of all similar sailboat designs in light wind.

Over- / underrigged

The Finngulf 391 DH has more rig than 86% of all similar sailboats, which indicates that the boat is significantly 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 38m² (409 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.

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	40.0 m	(131.4 feet)	12 mm	(1/2 inch)
Jib/genoa halyard	40.0 m	(131.4 feet)	12 mm	(1/2 inch)
Spinnaker halyard	40.0 m	(131.4 feet)	12 mm	(1/2 inch)
Jib sheet	12.0 m	(39.3 feet)	14 mm	(0.55 inch)
Genoa sheet	12.0 m	(39.3 feet)	14 mm	(0.55 inch)
Mainsheet	29.9 m	(98.2 feet)	14 mm	(0.55 inch)
Spinnaker sheet	26.3 m	(86.4 feet)	14 mm	(0.55 inch)
Cunningham	5.0 m	(16.4 feet)	12 mm	(1/2 inch)
Kickingstrap	10.0 m	(32.8 feet)	12 mm	(1/2 inch)
Clew-outhaul	10.0 m	(32.8 feet)	12 mm	(1/2 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.

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Finally

We are always looking for new photos. If you can contribute with photos for Finngulf 391 DH 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.