How small tugboats move massive ships

When compared to big vessels, tugboats are quite tiny and might seem weak to the eye.

But it's the function that matters, not the size. Discover how small tugboats actually move massive ships.

#engineering

[Interestingengineeringofficial]

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[ermytanio]

I'm more amazed by the cable they using to pull those massive ship

[Closet__Dweller]

To quote Tugs, "The tugboat, for its size, is the most powerful craft afloat."

[calebc.]

The tugboat, for its size, is the most powerful craft afloat. And the tugs are the power behind the docks and waterways that make up the a Big City Port.

[MrMijnaccount]

On tugboats you want thrust.
Thrust: This is created with surface of the prop. Surface is created with diameter and the size of the blades.
Pitch: The angle of the prop on the shaft which creates the theoretical movement forward with one rotation of the prop.
Slip/Efficiency: The difference between the theoretical and practical movement forward with one rotation of the prop. Less pitch is less slip and by that more efficient.
The power of a prop is a combination of surface and pitch. If you have a lot of surface you can't combine this with a lot of pitch of the blades because of the limited power of your engine.
So the conclusion:
1. A tugboat uses large props with a little pitch and low RPM what creates a lot of thrust with minimal slip but not so much speed.
2. A speedboat will use small props with a lot of pitch and high RPM what gives a lot of slip before the speedboat will reach higher speeds, the prop will be more efficient at higher speed.

Edit:
This is without talking about cavitation or ventilation. Which are very important things and can also give a lot of trouble.

Second edit:
Nobody asked. I just hated that when you talk about tugs you don't talk about the most important part which is the prop.

[laeeqkhan]

"Become a tug boat. Move shit that's 1000 times physically larger than you" - grizillionaire mindset

[XYZ_is_taken]

Well you know what they say

The tugboat, for its size, is the most powerful craft afloat.

[Thebreakdownshow]

I was watching this tug boat pull like a kilometre long log train through the river

[adi]

This is why diesel engines are the torque monsters in the car world, construction diggers and even at sea. High torque at low rpm is the goal here.

[gordieboi]

The tugboat, for its size, is the most powerful craft to float

[jaiden]

Damn I'm feeling really down
Tug boat: don't worry I am always here if you need help

[yash.]

Wow i learnedsomething new today, Thanks!
Tug-boats are the little big heros of the seas.

[catholicfemininity]

LoL, I'm here because I remember my childhood shows, Tugs and also theodore tugboat. lmao xD

[ks_]

It also helps that they're built with just enough boat to float the biggest engine they can fit.

[TheWarbonnet]

“The tugboat, for its size is the most powerful craft afloat. Captain Star and his tugs are the power behind the docks and waterways that make up Bigg City Port, This is tugs!”

[mishrachabra]

Finally ... one of the biggest mystery to my mind has now been answered 🤣🤣

[Dr_Mario]

Of course, tugboats are already quite powerful, as they use either medium size boat diesel engines, or even actual train (locomotive) diesel engines, to provide crapload of torque to the propellers (propeller design matters a lot too), just so they can push themselves through the water HARD, in order to be able to pull large ships out. Not to mention they have to use rather strong ropes to be able to tow without snapping. Extra horsepower and torque also make them much more versatile than just to tow, especially when fighting fires, as water would be under so much pressure which is necessary to be able to reach much further than the typical firefighter hoses if they have to fight fire from afar, to name a few reasons why strong engines make them more useful.

[adimeter]

designated spots where it's safe for tugboats to push - an example of info I came to learn. Thank you.

[mohammadkarim]

The tugboats don't move the vessel, they help the vessels move.

[jameskvo]

I love seeing the Svitzer tugs push huge oil and LNG tankers in the harbour near where I live