It Would Take a Titanic Raft of Flotsam to Float Two Actors


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Actual lifeboat from the Titanic, photo taken by a passenger of the rescuing ship: Image courtesy of the National Archives

Building a Raft Large Enough for Kate

Let’s assume that the door was actually twice as wide; perhaps it slides rather than swings. Then, the volume would be 2 x 1.6 x 0.0127 = 0.04064M^3, which would displace 41.656Kg of water. That’s still far less than Kate’s weight!

So, let’s also triple the door’s thickness; perhaps it was designed for security against burglars or gale-force winds. This new volume would be 2 x 1.6 x 0.0381 = 0.12192M^3, displacing 124.968Kg of water. Subtracting the new door’s weight, we have 124.968 – 54.864 = 70.104Kg.

Since Kate weighs a dainty 61Kg, her much larger door has an excess buoyancy of 9.104Kg to float her above the water. Jack, however, is still in the deep blue sea, and Rose would be too, if he tried to climb aboard.

Designing a Titanic Raft for Two Survivors

Kate’s door had the capacity to support 70.104Kg, which is almost 2Kg less than Jack’s weight. Since it had 9Kg excess buoyancy for Kate, let’s take an engineering shortcut and simply nail two of these super-sized doors together. Even with the nails, this arrangement would buoy both soulmates as they await rescue.

To duplicate the buoyancy required to support both characters, the pair would need a dozen of the original doors, in order to make a raft that meets our simplified standards for success.

We leave the calculations for the weight of all the extra nails to our industrious readers.

To Finally Sink this Titanic Raft

An inflatable raft weighs very little, and is very buoyant. Image by Klearchos Kapoutsis

Although any object that floats might assist a poor swimmer, the goal of staying afloat and above water on a “raft” depends on the volume and density of that raft.

In the “Titanic” film, Kate would not have been able to use a single door to remain above water, much less save Jack as well. These math calculations show that Jack would have had to nail together about a dozen standard doors into one improvised raft to have any hope of saving them both without lifeboats from the sinking Titanic.


The New York Times Store. Rare Piece of Titanic Door Recovered at Disaster Site in 1912. Accessed June 7, 2012.

Benson, T. Buoyancy: Archimedes Principle. NASA. (1996). Accessed June 7, 2012.

California Science Project at California State University Northridge. Density of Liquids. (Page 2). PDF. Accessed June 7, 2012.

The Engineering Toolbox. Water – Density and Specific Weight and Wood Densities. Accessed June 7, 2012.

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