Why Queen Mary 2 carries spare propeller blades everywhere she goes? QM2 technical explainer!

Why does QM2 carry spare propeller blades everywhere she goes? In this video we will find out why! — 🚢 My Cunard History Website: https://www.chriscunard.com/ 📚 Buy my books: https://www.chrisframe.com.au/books 👕 Buy cruise merch: https://chrisframeofficial.Teemill.com/ 🎶 Listen to The Big Cruise Podcast: https://thebigcruisepodcast.com/ 🛳️ Learn more about cruising at my Blog: https://www.chrisframe.com.au/ — CHAPTERS: 00:00 Queen Mary 2’s propellers 00:27 Why ships carry spare propellers 01:06 Custom Designed Propellers 01:24 Cavitation & its impact on propellers 02:14 Changing Propeller Blades 02:41 Benefits for QM2 to carry spares 03:04 Other ships that carry spares 03:27 Outro — QM2’s spare propeller blades are stored in a passenger area, at the forward end of Deck 7. They are sometimes referred to as ‘the Captain’s cufflinks’ and look like they could be an art piece. But they are actually functional and necessary pieces of equipment. Carrying spare propeller blades with the ship is a little like having a spare tyre for your car. If something happens to your tyre, you are able to swap the tyre out and hopefully continue on your journey. For QM2, which often travels to distant ports, it makes sense to carry a few spares. Especially since the ship’s propellers are custom designed. If a blade falls off or gets damaged, the spares are able to be fitted to the ship and the ship can continue on its way. When the ship is far from the shipyards where the usual maintenance is undertaken, it is far easier to have the spares already with the ship, than to have to send them to the ship. This is very important because, unlike with car tyres, you can’t just put a ‘standard propeller’ onto a ship. There’s not really such thing as a ‘standard propeller’ that fits most ships. And the reason for this is that every ship is different, and they are all subject to vibration and cavitation. The spinning of a ship’s propellers causes vibrations in the ship, particularly in the stern. Cavitation, which is the process by which air bubbles form on the propeller blades when they spin, eventually imploding when an area of low pressure is formed, makes these vibrations much worse. Cavitation can also cause damage to the propeller blades themselves, further increasing the level of vibrations. If you’re interested in learning more about cavitation, Casual Navigation has a great video explaining how it works here: https://www.youtube.com/watch?v=2cnKzCTJC_8 To counter these effects, the propeller blades for a ship have to be designed in such a way as to limit both vibration of the ship from the movement of the blades and cavitation. And for that reason, the blades are custom designed for the ship they are going to be used on. QM2 isn’t the only ship to carry spare propeller blades. If you can think of another passenger ship where the spare blades are carried in plain view, then please let me know in the comments. — Tags: #qm2 #queenmary2 #cunard #cunardline #shipbuilding #cruiseship #oceanliner — Imagery References: • Norwegian Sky / Norwegian Sun: NCL Media Kit • Silver Wind: Silversea Media Kit • Various contributors via Unsplash: -- Propeller by Darren Halstead: https://unsplash.com/photos/VAFwHaR8YA4 -- Car Tyre by Chinmay Jade: https://unsplash.com/photos/XNN9C8MG4KM -- Changing Tyre by Marc Kleen: https://unsplash.com/photos/GeeZAavtFy4 • QM2 drone footage all shot by Luke Morrison who obtained approval for a flight path near the ship. • Cavitation Damage / Erik Axdahl / CC BY SA 2.5 Generic / https://tinyurl.com/http0009 • QE2 in Bremerhaven / Dashers / CC BY SA 3.0 / https://tinyurl.com/httpqe2 • Lusitania alongside NYC / Library of Congress / Public Domain / https://tinyurl.com/http1907 • Cavitating Propeller / Public Domain / https://tinyurl.com/http9989