I reckon that the propellers were perhaps the most expensive single part of the ship just for the weight of all that material alone and then there was all the precision engineering and balancing. I bet the bosses hated it when a prop was dropped.

Silicon bronze was invented for ship propellers as it resists corrosion. As a side benefit, it also flows much better than traditional bronzes in casting, and today it is the most widely used bronze for sculpture.

@auntbarbara5576

Жыл бұрын

Aunt Barbara adores you! and silicone.

Done that a few times and it's near enough a manual operation today, though the prop is in one piece unless it's controllable pitch. The prop is pretty tight on the shaft and box wedges were and are still used to force it off. The nut - called a pilgrim nut - may be hydraulically fitted these days and as the keyway was a stress-raiser, most today are keyless and rely on hydraulic tensioning or glue. Not much has changed. One shipping company's crew changed a prop at sea in the good old days of general cargo, but that's pretty impossible today.

Thanks to "The Great Big Move" for helping to keep nautical history alive for others to view and enjoy. People think that changing a tire on their car is hard, I would hate to be on the propeller changing team. lol Thanks again for your time and work.....

Nice topic that I’ve never put much thought into, but changing propellers is more common than expected. Great video!

I'd wondered for decades how they fitted propellers? it simply hadn't occurred to me that the original design/building work would involve fitting lugs to the hull, it does at least make an impossible job approachable..... For me a brilliant and really educational video, thanks for posting. :)

It’s my birthday tomorrow! What a great gift - a new upload from GBM!!!!! This made me smile since this is still my favorite channel!!!

I worked in a shipyard back in the 90's and would occasionally need to make the wrench used to tighten/loosen the collar nut. The wrenches had an inside span of ~4 feet and was cut out of 2" thick steel.

@beachbum4691

Жыл бұрын

quote > "The wrenches used had an "inside span of ~4 feet" and was cut out of 2" thick steel" that really gives you an idea of the scale of what was going on and something of an insight into the hazards associated with great weight.......... thanks for your comment EriK. :)

@eherrmann01

Жыл бұрын

@@beachbum4691 Thanks for the reply. I saw and did some very cool things during my time in the 'yard. Unfortunately, I also saw some terrible accidents. Shipbuilding is an extremely dangerous occupation and tons of steel are very unforgiving of those who are not alert and safety conscious at all times.

I could make SOOO much hummus with these

I never even thought about this, but still extremely interesting

Brilliant. Thank you for sharing.

Very interesting process, always a big fan of the mechanics of the whole thing.

I never realized that ships would or could lose a prop while at sea. Makes sense though.

@auntbarbara5576

Жыл бұрын

Aunt Barbara adores you! 😘

Great Video, what a dangerous job.

Holy cow! You are back!!!

I've always wanted to learn about this

I love the thumbnail of the Olympics propellers

great short video - thanks

I'd always wondered about this! Thanks for the quality content as always TGBM!

I was waiting for the photo of Olympic. Most people refer to it as Titanic and I was expecting the same here, but I'm happy that you didn't.

Today some ship keep spare propeller blades on deck, the famous Queen Mary 2 is such an example.

Could you do a video about the S.S. Deutschland (1900) and the Kaiser-class Ocean Liners? And also the S.S. Lapland?

You should do a video on how to dry dock a ship

you’re back!!! i thought you fell overboard lol.

I still want to know how was the space between the propellers and the shaft water tight, why didnt water just spew/leak in?

@kilianortmann9979

Жыл бұрын

The space between the prop and the shaft does not need to be water tight, the shaft itself has a seal, where it enters the hull of the ship. These seals are called stuffing box, they are essentially rings of fibrous material like flax or hemp, impregnated with wax or tallow. The rings can be compressed in the axial direction, so that they expand around the circumference of the shaft. This type of seal may leak a little bit, but the bilge pumps can take care of that easily.

@mrb.5610

Жыл бұрын

@@kilianortmann9979 There's one on the older style of water stop cocks - it's under that nut where the shaft comes out of the tap's body !

quote "Erik_H" below > "The wrenches used had an "inside span of ~4 feet" and was cut out of 2" thick steel" (Me>)that really gives you an idea of the scale of what was going on and something of an insight into the hazards associated with great weight.......... thanks for your comment EriK. :)

How fascinating! Probably a stupid question, but how do the propellers get so beat up? I noticed the gouges in some of them. Friction from water??

@thetman0068

Жыл бұрын

It can be many things. Over long periods, water itself can beat up the blades. There is a phenomenon called cavitation which put simply, are tiny air bubbles that form when a propeller spins at a high linear speed. When the bubbles pop the water around it rushes to fill the space, which creates a tiny jet of water that can damage propellor blade surfaces. Over the course of thousands upon thousands of revolutions over the course of a ship’s career, this tiny point of damage can spread. But more often, propellers would become damaged by striking underwater rocks, reefs, sandbars, or semi-submerged debris.

@allangibson8494

Жыл бұрын

@@thetman0068 Cavitation is actually vacuum bubbles not air. They collapse at very high speed and generate temperatures of tens of thousands of degrees when that happens. The metal boils under those conditions. Rinse and repeat to form a hole.

i thought it might be cool to raise one of titanics propellors....but that now we see how they are installed.....and being half buried in mud....thats probably not possible XD

Aunt Barbara adores you!

How were they able to drop the propeller blades while out on the open sea?!

Any info on how they kept sea water from entering the ship through the propeller shaft?

@Marc816

Жыл бұрын

Very good sealing & powerful pumps for the water that did get through.

@superkamehameha1744

Жыл бұрын

@@Marc816 how to seal a shaft that's spinning?

@Marc816

Жыл бұрын

@@superkamehameha1744 It's done that way on cars all the time.....water pump shafts, power steering pump shafts, front and rear main bearings in car engines. It's the same for ship propellers.

i read your name as the great big minute

I always wonder why triple screw ships are so rare? compared to twin or quadruple screw ships

@thabg007

Жыл бұрын

maybe its like a twin engine plane, twin prop 1 rotates clockwise, 1 rotates counter clockwise to cancel out gyroscopic forces

@cybergothiche2

Жыл бұрын

​@@thabg007 I think you're right. There will always be two props rotating in one direction and one in the other, making the ship easy to turn one way, and sluggish the other.

@ryanhelton1865

Жыл бұрын

Not in recent years. I think there’s only QM2 what has quadrupled. The majority of royal Caribbean ship have triple and rest of cruise ships rend to too have twin.

I love those ships!!!!!!!!!!!! bring back those Glory Days!!!!!!!!!!!!! and to hell with this modern world!!!!!!!!!!!!!