How much fuel does a ship burn in an hour?

 At economical speed, the engine of a large container ship consumes 1,660 gallons (6,284 liters) of heavy fuel oil an hour. The answer varies enormously depending on the vessel.

A large container ship like the Emma Maersk is powered by a Wartsila Sulzer RTA96-C 14-cylinder diesel engine, the largest single diesel unit in the world, delivering a maximum power of 108,920 hp. The thermal efficiency of the engine is over 50% at maximum economy. Fuel consumption of large marine diesel engines would be more than 100 metric tonnes per day, depending upon the load, speed, and the weather and sea conditions.

Cruise ships operate differently from cargo vessels. A medium-sized cruise ship carrying 1,500 passengers, running on three diesel generators at 18.5 knots, burned 3.75 tonnes of heavy fuel oil per hour, or 38 US gallons of fuel oil per mile. A large container ship burning the low-sulfur diesel equivalent would see usage jump to 1,880 or more gallons per hour, since heavy fuel oil carries significantly more energy per gallon than road diesel.

Warships burn fuel at different rates depending on speed and power plant configuration. The USS Midway burned about 260 gallons per mile at cruising speed, and at maximum speed of 33 knots that figure would quadruple.

A large ocean liner like the Queen Elizabeth II consumed a gallon of diesel fuel for every thirty inches of passage at maximum speed in rough seas. At its maximum speed equivalent of 34 knots, it would have consumed over 82,000 gallons of fuel over the course of one hour, though it generally cruised at 28.5 knots, burning a gallon of fuel to go about 50 feet.

The easy conversion for estimating purposes is horsepower multiplied by 0.055 equals gallons per hour at full throttle, so an 80,000 hp engine consumes roughly 4,400 gallons per hour, not including generators.

Why is a submarine called a boat and not a ship?

 It is a historical convention that goes back to definitions: ships carry boats. Since early submersibles could be carried by ships, and were often tended by ships called "submarine tenders", they were boats, and the naming convention held.

The earliest modern submarines, dating to about 1912, were much smaller than those used in WWII and later, and were often carried by ships to a place near their objective because they typically lacked the fuel needed to make long return trips.

The first practical submarines were developed in the 19th century as small vessels for 1-4 crew that were typically transported aboard larger vessels and deployed from them. Even when submarines became large enough to be considered more ship than boat, there remained a self-deprecating pride among the crews to continue using the diminutive term. The German term for a submarine is unterseeboot which became anglicized to U-Boat, a term that was popularized in WW1 and WW2.

Submarines are very much considered ships however the earliest submarines to enter naval service were formally titled Submarine Torpedo Boats. Submarine Torpedo Boat was rapidly shortened to Submarine officially but the monicker "Boat" stuck as an informal type name and submarines have been known as boats ever since. The Navy's official designation is Ship, Submersible, Nuclear for fast attack subs, and Ship, Submersible, Nuclear, Ballistic for the ballistic missile launching subs.

By the time submarines had grown into ships, the tradition of calling them "boats" had been established and has remained until today, at least to some extent. Make no mistake, a vessel that is 377 feet long and displaces 8700 tons is indeed a ship, regardless of tradition.

Isn’t it strange that a ship made of heavy iron floats?

 It’s just water displacement. Remember that water exerts increasing amounts of force as you go deeper—and rapidly so.

The most fascinating example if that of the aircraft carrier. When you look at it, you’d never guess that it would float.

The trick has to do with the weight at the bottom of the ship.

It is a giant weight that’s constantly trying to pull the boat down. But the displacement of water makes the ship float perfectly, causing this tension to stabilize the ship perfectly.

Think of a balloon with a weight tied to it. It might go down. It might go up. But it will never flip over. That subsurface protrusion was discovered in the 19th century as a way of drastically reducing drag on the ship.

Regardless, oceanic vessel engineering is highly underappreciated.

Which would win: the weakest warship in service today or the strongest ship 300 years ago?

 One of the most powerful ships in the world in 1720 was HMS Royal Sovereign . She was a hundred-gun ship of the line and the flagship of the Royal Navy.

The heaviest gun on board was the 32-pounder. Its theoretical range was approximately 3,700 meters, but its practical range was 650 meters. They were hand-loaded and fired, and please note that they were aimed either straight ahead or directly to one side.

No turrets here! They can be swung to either side, but their firing arc is rather limited.

There are currently many options for the weakest ship, but one of the weakest ships in the French Navy in terms of firepower is the

French Navy's

training ship. The example shown is the

Guépard ( Léopard class ).

Its heaviest weapon is the 20mm Oerlikon cannon in a turret. Its effective range is 3000 meters, with a maximum range of 6800 meters.

Note also that one is powered solely by sail, with a speed of approximately 10 to 14 knots. The other is motorized, with a speed of over 25 knots.

So, theoretically, the Cheetah could simply surround HMS Royal Sovereign , strike it from all angles, and well beyond the range of the British guns. Those 20mm cannons would tear through the wooden hull, start fires, and simply devastate the crew.

Canon Oerlikon 20mm

If, by some miracle, a cannonball were to strike the Cheetah , it would bore a solid hole in it, but unless it struck something flammable or even hit a hole in the ship to let water in, it would be unlikely to sink it.

There were even angles where the English gun couldn't even hit the Cheetah , but the 20mm guns easily raked HMS Royal Sovereign from any angle. A 20mm would probably be able to hit the stern and penetrate through the bow of HMS Royal Sovereign , and ships of the line had few guns at the bow or stern.

There simply is no competition.

Can a whale flip a cruise ship?

 Kind of the opposite as cruise ships can and do run into whales and kill them

The only whale that would be able to flip over a cruise ship is a kaijiu, but sadly for us it isn’t real.

This would be the only whale that can flip over a cruise ship or cause it to entirely sink.