ultramarin marine translations
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nl draaiproef    
de Drehkreisversuch Test zur Feststellung des Drehkreises eines Schiffs und des Verhaltens der Ruderanlage und der Steuerung des Ruders bei Kursveränderungsmanövern. Der Test wird üblicherweise nach beiden Seiten bei Höchstgeschwindigkeit mit Hartruderlagen und Ruderlagen von 15° ausgeführt. Der Drehkreis sollte sinnvollerweise über wenigstens 540° gehen, um die wichtigsten Parameter des Versuchs zu erheben.
Im Versuch lassen sich außerdem weitere Kennwerte bestimmen, so z.B.
- taktischer Durchmesser
- Vorausgang
- Seitenversetzung
- Geschwindigkeitsverlust bei stetiger Drehung
- Kursänderungsdauer über 90° und 180°
Gemessen werden überdies der maximale Vorausgang und die maximale Seitenversetzung.
en circle test
turning test
test used to determine the ship’s steady turning radius and to verify the behaviour of the steering machine and rudder control during course-changing manoeuvres. The test should be performed to both port and starboard at maximum speed, with a maximum rudder angle and with a rudder angle of 15 degrees. It is necessary to do a turning circle of 540º at least to determine the main parameters of this trial.
This manoeuvre is also used to determine other characteristic parameters such as:
- tactical diametre
- advance
- transfer
- loss of speed on steady turn
- times to change heading 90º and 180º respectively
The maximum advance and maximum transfer can also be measured.
fr essai de giration  
     
  The turning circle test is devised in the following phases:
Approach phase: The ship sails in advance, in a straight line at a constant speed U and with the rudder in neutral position.
Manoeuvre phase: This begins when the constant rudder angle d is applied at any of the sides. It is divided into three phases:
- First phase: Starts at the instant the rudder begins to deflect from the neutral position and finishes when it reaches the desired d value. During this stage, the speeds are practically null.
- Second phase: Here, the accelerations coexist with the speeds. In the last part of this stage, equilibrium is obtained between the forces intervening in the ship’s turning circle and the accelerations tend to reduce to zero.
- Third phase: When this equilibrium is reached, the ship begins to perform a turn of constant radius R. In this phase the ship’s speed is reduced by 60% from the speed it had when the turning circle was initiated.