Hi!I am a ship science student in Southampton and I am writing an assignment on SS Framce but I can`t find much information about the hull structure and propulsion system. Do anyone of you now where to get this information?
Thank you so much for the information, Raoul. I am just wondering, since she was build to be one of the fastest ocean liners, what extra feature did they do with the hull and propulsion system to give her this advance?
While the SS France was fast, she wasn't that fast. 35 knots top speed is not that much faster than what the older Queen Mary and Queen Elizabeth could do. They could reach a top speed of 31.75 knots while pushing 80,774 tons through the water on 4 steam turbines rated at 160,000 shaft horse power.
What made the SS France faster than the Queens was the 175,000 shaft horespower pushing only 66,348 tons through the water. Although longer, the SS France was lighter in weight.
Just like racing cars, the stronger engine pushing less weight is usually faster.
Meanwhile, the SS United States was significantly faster than the SS France, or any other monohull ship ever built. The SS US had 8 Foster Wheeler 1,000 psi boilers, 4 Westinghouse turbines and 4 propellers rated at 248,000 shaft horsepower (185 MW) pushing just 53,259 tons. It could reach a reported top speed of 44.7 knots during sea trials. On its maiden trans Atlantic voyage, the SS US average 35.59 knots.
The Maiden Voyage
During the builder's trials in June 1952, which were followed by U.S. Navy trials, the SS United States exceeded all expectations. Print media reporters observing the trials from nearby ships noted in their stories that there could be no doubt that the new liner would snatch back the Blue Ribbon for the United States. On July 3, 1952, the SS United States backed away from United States Lines' Pier 86 in New York City and headed for glory. Captain Harry Manning, Commodore of the United States Lines, was noncommittal about a record-breaking run. Disappointment temporarily ensued when the SS United States encountered fog during her first day out, and Manning prudently reduced speed. When the fog lifted, Manning ordered full power and the liner leapt ahead into the North Atlantic. Despite the delay, as well as gale force winds and heavy seas approaching the coast of Europe, the SS United States reportedly handled like a thoroughbred with its neck stretched toward the finish line. The liner steamed seemingly without effort in heavy swells, for a time exceeding 36 knots with no apparent vibration in the stern. By the time the SS United States reached Bishop Rock, England, there was no doubt that the North Atlantic speed record had been smashed. The SS United States easily bested the record held for 14 years by the Queen Mary. The eastbound crossing had an average speed of 35.59 knots.
What made the SS United States so much faster? More Horsepower and Less Weight.
Thank you, your information is really helpfull. I get real confused with all that I read.
So what made it lighter was that most of the superstructure and some parts of the hull was made of alliminium, right? But what made United states so much lighter?
Strange that they wrote that SS France had such an advance in the hull design and populsion system when really it was only lighter than the rest, untill SS United States came. How much later was that actually?
So how was the design of the hull? I read that it was a modified version of the Normandie`s with similar arched "whale back" bow, but with an updated stern. Do any of you have any more detailed knowledge about the hull design?
I really appreciate all the knowledge and information you shear with me.
My point was, MORE propulsion horsepower and less weight is what these ships faster.
All these ships have steel hulls. The SS France and the SS US had aluminum superstructures, which made them weigh less than the Queens.
Hull design helps top speed some, but the major increases in speed comes from engine horsepower.
Most ships hull designs have a best fuel efficient speed around 19 to 20 knots.
Improving the hull design may change the best fuel efficient speed a couple of knots at most. When the ship is traveling faster than its best fuel efficient speed, the horsepower required to make it go faster shoots up dramatically.
How dramatically? The SS France could attain speeds of 35+ knots on 175,000 shaft horse power. The same ship modified into the SS Norway could attain a top speed of 25+ knots on half the horsepower, resulting from losing half the propulsion. Therefore, it only required 87,500 shaft horsepower to reach 25 knots. The last 10 knots in speed, to get to 35+ knots, required another 87,500 shaft horsepower.
you could see this better if one were to draw a graph. On the vertical axis, draw two equally spaced points, on the horizontal access, draw seven equally spaced points.
Starting at the crossing point (zero), make a point 5 points to the right, and one point up. Then make another point seven spaces to the right, and two points up. Then draw an exponential line from zero through both points.
The point of this exercise is to show that the first 5 points to the right consumed the same amount of horsepower as the final two points to the right. So one could say for the SS France to travel at 35 knots, it was consuming 200% more horsepower or fuel than traveling at 25 knots.
Sufficent horsepower is the main factor to acheive higher speeds.
Alright, think I understand what you mean, thank you My drawings wasn`t the best but I get the consept.
But do you know if the hull was welding or ribotting? Since this also affect the weight, right? And also, is it still under Bureau veritas?