Bigger, Bigger, Bigger - Oil Tankers

[Kitsune]

I was reading that the Batillus class supertankers were the largest (weight wise) Tankers that were ever built. The Knock Nevis supertanker is the longest overall. The four sisters were scrapped after less than ten years for most of them with the final having been scrapped in 2003. The Knock Nevis is now a stationary platform.

What I am curious about is what happened to the ever biggest supertanker? Is there a reason why ever larger vessels are not economical?

[Stuart]

I was reading that the Batillus class supertankers were the largest (weight wise) Tankers that were ever built. The Knock Nevis supertanker is the longest overall. The four sisters were scrapped after less than ten years for most of them with the final having been scrapped in 2003. The Knock Nevis is now a stationary platform.

What I am curious about is what happened to the ever biggest supertanker? Is there a reason why ever larger vessels are not economical?

The primary reason why the Batillus class went to the breakers was that they were steam turbine powered. That made them expensive to operate, temperamental and requiring the services of engineers who are getting to be in short supply. Most merchant ships are diesel-powered and steam is really unusual these days, Also, ships this large have severe navigational restrictions and that limits their flexibility,

[Sea Skimmer]

Batillus was the heaviest class as originally built, but once Knock Nevis was jumboized she became heavier as well as longer. Only a handful (7 or 8 I think) of ships above 400,000 deadweight tons were ever built because the economies of scale start to run out at that point. Bigger ships are ever cheaper to operate when moving, but loading and unloading times become excessive, reducing the number of possible trip between overhauls, and it all interferes with the schedules of smaller ships using the same terminals.

[Kanastrous]

I should think that the difficulties of transiting certain waterways and being able to dock at certain facilities with super-insane-ginormous ships would be a problem for operators, too.

[Ma Deuce]

Only a handful (7 or 8 I think) of ships above 400,000 deadweight tons were ever built because the economies of scale start to run out at that point.

You mean 500K DWT right? Because in that weight class I can name the 4 Batilluses, the 2 Esso Atlantics, and of course Jahre Viking/Knock Nevis.