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Review of Dehler 34 (1983)


Dehler 34 (1983)
Dehler 34 (1983) anno 1985. The Optima 101 version of the Dehler 34 can be identified by the tiny circular windows at the deck.


Basic specs.

sail specifications
The Dehler 34 (1983) is a sailboat designed by the Dutch maritime architect E. G. van de Stadt in the early eighties. A few thousand boats have been produced. The Dehler 34 (1983) is built by the German yard Dehler Yachtbau GmbH.

Looking for a new boat? Find a Dehler 34 (1983) or similar boat for sale

Hull

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


Interior

The boat is equipped with 3 cabins, 6 berths and 76.0 liter fresh water capacity.


Rig
Rig
Dehler 34 (1983) anno 1987 with spinnaker. in Kroatien, Gebiet Kornaten
Rig
Rig of Dehler 34 (1983) anno 1984. The Optima 101 version of the Dehler 34 can be identified by the tiny circular windows at the deck.

The boat has more than one rig.

One option is a fractional rig. 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

The Dehler 34 (1983) has been built with different keel alternatives.

Fin keel

One option is a fin keel. The fin keel is the most common keel and provides splendid manoeuvrability. The downside is that it has less directional stability than a long 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.

Dehler 34 (1983) can enter most marinas as the draft is just about 1.70 - 1.80 meter (5.58 - 5.88 ft) dependent on the load. See immersion rate below.

Fin keel

Another option is 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 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. As the surface of a fin type keel is just a fraction of the total wet surface, the difference between an iron keel and a lead keel can in reality be ignored for cruising yachts.

The boat can enter most marinas as the draft is just about 1.70 - 1.80 meter (5.58 - 5.88 ft) dependent on the load. See immersion rate below.

Fin keel

Another option is a fin keel. The fin keel is the most common keel and provides splendid manoeuvrability. The downside is that it has less directional stability than a long keel.

This keel is also made of iron.

The boat can enter most marinas as the draft is just about 1.75 - 1.85 meter (5.74 - 6.04 ft) dependent on the load. See immersion rate below.


Engine

Dehler 34 (1983) may be equipped with an inboard Yanmar diesel engine at 18 hp (13 kW). Calculated max speed is about 5.5 knots

The fuel tank has a capacity of 38.0 liters (10 US gallons, 8 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 Dehler 34 (1983) is 2.16, indicating that this boat would not 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 7.0 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 Dehler 34 (1983) is about 189 kg/cm, alternatively 1058 lbs/inch.
Meaning: if you load 189 kg cargo on the boat then it will sink 1 cm. Alternatively, if you load 1058 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 Dehler 34 (1983) is 17.8 - 18.8.

Low High 18% 0 50 100
Comparing this ratio with similar sailboats show that it is more comfortable than 18% of all similar sailboat designs. This is a comfort value significantly below average.


L/B (Length Beam Ratio)

What is L/B (Length Beam Ratio)?

The l/b ratio for Dehler 34 (1983) is 2.97.

Slim Wide 73% 0 50 100
Compared with other similar sailboats it is more spacy than 73% of all other designs. It seems that the designer has chosen a slightly more spacy hull design.


Ballast Ratio

What is a Ballast Ratio?

The ballast ratio for Dehler 34 (1983) is 40%.

Low High 46% 0 50 100
This ballast ratio shows a righting moment that is higher than 46% of all similar sailboat designs. A righting moment (ability to resist heeling) just below average.


D/L (Displacement Length Ratio)

What is Displacement Length Ratio?

The DL-ratio for Dehler 34 (1983) is 190 which categorizes this boat among 'light racers'.

Heavy Light 76% 0 50 100
76% 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 Dehler 34 (1983) with ISO 8666 reference sail is 18.9, with a 135% genua the SA/D is 21.8.

Low High 79% 0 50 100
The SA/D ratio indicates that it is faster than 79% of all similar sailboat designs in light wind.


Over- / underrigged

Low High 79% 0 50 100
The Dehler 34 (1983) has more rig than 79% of all similar sailboats, which indicates that the boat is significantly overrigged.


RSP (Relative Speed Performance)

What is Relative Speed Performance?

The Relative Speed Performance for Dehler 34 (1983) is 79

Slow Fast 79% 0 50 100
The relative speed performance is 79 which means that a it is faster than 79% of all similar sailboat designs.


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 32m2 (344 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.

mainsail specifications genoa specifications spinnaker 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
Fractional rig
UsageLengthDiameter
Mainsail halyard 32.0 m(105.2 feet)10 mm(3/8 inch)
Jib/genoa halyard32.0 m(105.2 feet)10 mm(3/8 inch)
Spinnaker halyard32.0 m(105.2 feet)10 mm(3/8 inch)
Jib sheet 10.1 m(33.1 feet)12 mm(1/2 inch)
Genoa sheet10.1 m(33.1 feet)12 mm(1/2 inch)
Mainsheet 25.2 m(82.8 feet)12 mm(1/2 inch)
Spinnaker sheet22.2 m(72.9 feet)12 mm(1/2 inch)
Cunningham4.2 m(13.8 feet)10 mm(3/8 inch)
Kickingstrap8.4 m(27.6 feet)10 mm(3/8 inch)
Clew-outhaul8.4 m(27.6 feet)10 mm(3/8 inch)
Fractional rig
UsageLengthDiameter
Mainsail halyard 30.8 m(101.0 feet)10 mm(3/8 inch)
Jib/genoa halyard30.8 m(101.0 feet)10 mm(3/8 inch)
Spinnaker halyard30.8 m(101.0 feet)10 mm(3/8 inch)
Jib sheet 10.1 m(33.1 feet)12 mm(1/2 inch)
Genoa sheet10.1 m(33.1 feet)12 mm(1/2 inch)
Mainsheet 25.2 m(82.8 feet)12 mm(1/2 inch)
Spinnaker sheet22.2 m(72.9 feet)12 mm(1/2 inch)
Cunningham4.1 m(13.4 feet)10 mm(3/8 inch)
Kickingstrap8.2 m(26.8 feet)10 mm(3/8 inch)
Clew-outhaul8.2 m(26.8 feet)10 mm(3/8 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.



Finally

We are always looking for new photos. If you can contribute with photos for Dehler 34 (van de Stadt) 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