She Turned Two Points In 37 Seconds

Introduction:

• Edward Wilding, a naval architect from Harland & Wolff, presented data on the turning characteristics of the Olympic and Titanic during the British Inquiry.
• Tests on the Olympic showed it took 37 seconds to turn two points (22.5°) at 21.5 knots.

Turning Characteristics:

• The Titanic’s turning circle was analyzed using data from sea trials and tests on the Olympic.
• Key parameters include advance, transfer, tactical diameter, and final diameter.
• The ship’s speed decreases during a turn due to increased hydrodynamic drag.

Phases of a Turn:

• There are several phases to a turn: approach, rudder deflection, build-up of hydrodynamic forces, and steady-state turn.
• The ship’s speed, heading angle, and drift angle change during these phases.

Modeling a Turn:

• A mathematical model was developed to simulate the Titanic’s turn.
• The model includes equations for speed, heading angle, and drift angle over time.
• The Titanic’s steady-state turning speed was about 17 knots, with a drift angle of 8° and a heel angle of 6°.

Zig-Zag Maneuver:

• The Titanic’s maneuver to avoid the iceberg involved a zig-zag turn, with the helm shifted from hard-astarboard to hard-aport.
• The model shows the ship’s heading and position during this maneuver, highlighting the time taken to check the swing and change direction.

Collision with the Iceberg:

• The classic story of the Titanic’s collision was analyzed, including the timing of the lookout’s warning, the helm orders, and the ship’s response.
• The ship turned about one point (11°) before striking the iceberg, not two points as previously thought.
• The iceberg was seen fine off the starboard bow, and the ship struck it about 20 to 25 seconds after the hard-astarboard order was given.

Engine Orders:

• There is conflicting evidence about whether Murdoch ordered the engines full speed astern.
• The engines played little or no part in the collision avoidance maneuver.

Iceberg Damage:

• The damage to the Titanic was along the forward starboard side over a distance of about 200 to 250 feet.
• The damage was caused by impulsive strikes along the hull, creating several non-continuous openings.

Summary:

• The Titanic’s turning characteristics and collision dynamics were analyzed in detail.
• The ship’s response to helm orders and the timing of events were reconstructed using mathematical models and eyewitness accounts.
• The analysis provides a clearer understanding of the events leading up to the Titanic’s collision with the iceberg.