The Propeller Blade Mysteries
Question: How many blades did Titanic‘s propellers have, and what were their sizes?
Answer: Her center prop seems to have had three blades not four, as is commonly imagined; each of her wing props had three blades each, as well.
The two outboard wing propellers on the Titanic were each 23 ft 6 inches in diameter, sporting 3 blades each, with the blades bolted onto the heads. Their pitch was 35 ft. By way of comparison, the Olympic‘s original wing propellers were the same size and had the same number of blades, but had a pitch of only 33 feet. The Olympic, when first completed, sported a 16 ft 6 inch center propeller. It was made of a single cast, and had 4 blades. It has been often assumed that the Titanic‘s center propeller was essentially of the same, or of the exact same, design as her sister’s, especially since the Britannic was eventually fitted with a 4-bladed propeller identical to Olympic‘s.
This photograph is often said to be the Titanic in early 1912. It is not. This photograph actually is of the Olympic, and it was taken on January 29, 1924, nearly a dozen years after the Titanic sank. There are no known photographs of Titanic showing her central propeller in place; all of the ones available at this time are actually of the Olympic. If they are labeled “Titanic“, they are mis-captioned. As such, the photographs of Olympic‘s propellers can not be used as proof that the Titanic had a four-bladed central propeller. (Harland & Wolff photo 1796, Courtesy Jonathan Smith Collection)
However, maritime researcher and author Mark Chirnside has recently written an article entitled, “The Mystery of Titanic’s Central Propeller.” (Published in Titanic International Society’s quarterly journal Voyage, No. 63.) Therein, he cites original documented evidence from a period Harland & Wolff engineering notebook which gives the propeller and engine specifications for a number of vessels, including Olympic and Titanic. This evidence seems to suggest that Titanic was fitted with a 3-bladed center propeller with a diameter of 17 ft 0 in. In light of further photographic evidence (either of the wreck, or in original photographs from the period, either contradictory or supportive), this is the best evidence that we have on the design of TItanic’s center propeller. I would highly recommend picking up a copy of Mr. Chirnside’s full article so that you can review this new and fascinating information for yourself. — My thanks to Bruce Beveridge for his willingness to answer a couple of questions on this particular subject, and to Mr. Chirnside for producing the original research on this matter.
Recommended Reading:
- “TITANIC’S CENTRE PROPELLER: DOSSIER” by Mark Chirnside (updated 2016)
- “Unraveling the Mystery of Titanic’s Center Propeller“, by Bob Read (requires Adobe Acrobat PDF reader)
- On A Sea of Glass: The Life & Loss of the RMS Titanic by Tad Fitch, J. Kent Layton and Bill Wormstedt
- Report Into the Loss of the SS Titanic, by Sam Halpern, et al.