|By Mary Zoccola
In December the sinking of the RMS Titanic was re-enacted in Carderock's Maneuvering and Seakeeping Basin (MASK). Star Dust Visual, Inc., a production company, staged the re-enactment for a two-hour Discovery Channel program entitled "Titanic Science," airing on April 25 at 8 p.m. and again on May 2 and May 3.
The goal was to determine the Titanic bow's path to the ocean floor. To do this, a camera crew recorded the model as it descended into the water. They used two types of position data: video with underwater camcorders and rectangular coordinates (three-axis position data) using the acoustic tracking system in the MASK.
Dave Bochinski (56) and Dan Gilbreath (56) were involved using the rectangular coordinates. The position information was transformed from a set of coordinate pairs to a 3D graphic format, resembling a match stick falling to the bottom. Ultimately, Star Dust officials will use this graphic format to generate a realistic looking, 3D animation of the ship's bow as it sank.
The tracking system uses 20 hydrophones located at the perimeter of the MASK. Hydrophones, located on the model, detect pings. A computer records the time of flight of the ping through the water. The data calculate the X, Y, and Z locations in the basin. This system is normally used on a Radio Controlled Submarine Model (RCM) during testing in the MASK.
The Carderock Division became involved in this endeavor following an inquiry from Carey Filling of Nichols Advanced Marine, Inc. requesting the use of the MASK. Filling said that the 35-foot deep part of the Seakeeping Basin would provide the necessary depth to approximate the scaled depth where the Titanic sank.
Nichols supplied an accurate hydrodynamic model of the forward section of RMS Titanic. The model was filmed descending into 35 feet of water during a lengthy series of sinkings in the MASK. The five-foot model was sunk repeatedly. The purpose was verification of how that part of the ship went to the ocean bottom. Tests covered the trajectory and terminal velocity as the forward portion sank two miles in the ocean.
Very little is known about the sinking dynamics of the Titanic and ships in general. The problem is to determine, from the bottom wreckage, the amount of damage caused on the surface, during the descent and the bottom impact.
Initially, other than the use of facilities, Nichols personnel asked for little or no technical assistance from the Carderock Division. In discussions with the company, Lew Motter, Head of the Seakeeping Department (55), explained the Division's capabilities and gained a clearer perspective of tasks involved in the re-enactment. With an understanding of the proposed tests, Motter offered technical suggestions to Nichols. Impressed with these ideas and our expertise, Nichols proposed increasing the Division's role in the project. Subsequently, the Maneuvering and Control Department (56) was tasked to track the model as it sank.
The Facility Engineering and Operations Department (51) ensured that the basin water was clear for underwater photography and provided power for lights and cameras. The Seakeeping Department (55) provided coordination for the operations. Divers, normally used by the Carderock Division, were hired by Star Dust to film underwater scenes and to recover the model.
The experiments were a great success after a rocky start. The model was delivered at the last minute. Since ballast information is impossible to determine accurately, several alternative ballast conditions were tried. The first few were obviously not correct. However, the good news is that for most of the ballast conditions the bow sank in a similar way. It sank with a cyclic motion. The bow would start down first and could go down in as much as a 60-degree angle. It could reach speeds up to 27 knots. At this point the bow would pitch up to as much as 10 degrees, and slow down.
The cycle would repeat until the vessel hit bottom. The period of the cycle varied with ballast condition. Velocity of the vessel on impact would vary depending on where in the cycle it was when it encountered the bottom.
From the first time Star Dust visited Carderock, they were impressed with the facilities. As noted earlier, they ultimately expanded the scope of their project to the delight of the Division. In addition to the actual model sinking test, Star Dust asked to film their War Room scene at Carderock. The filming of the war room scene took place on the side of the MASK using the basin as background.
It took more than 30 hours, compressed into two and a half days, to complete the work. The Public Affairs Office (001) provided support for the many visitors, including reporters from WJLA Channel 7 and the Baltimore Sun. Security did an outstanding job, quickly processing the many visitors and overcoming the problems of the film crew's unusual schedule. One notable person, and a star of the show, was the British naval architect Robin Williams. The team of experts also included members of the SNAME Forensics Panel.
Editor's Note: Lew Motter, Tom Warring and Jim Scott assisted with this article.
For More Information Contact:
Mary Zoccola at ZoccolaMA@nswccd.navy.mil or (301) 227-1165.