I have been reading a book called: Ships: A Visual Encyclopedia; by David Ross-Amber Books Limited-London.
I originally bought the book because it had a good cross-section of all the submarines built over the last 150 years. I like submarines. It turned out to be much more of a philosophical journey than I was expecting.
A Ship, any Ship, costs a Kings Ransom to built. Once built, it costs another Kings Ransom to run. They are very expensive in every way. Every ship ever built had an intended purpose. Some, actually many, were built where their intended purpose became essentially obsolete before or immediately after they were built and were used very little. Many others, of debatable design, had extraordinarily long service lives. Still others, of very good to excellent design, sank at anchor or were piled up by poor seamanship when they were fairly new.
I could write a book on my speculations but I want it to fit on this post. I believe there is a reasonably simple formula to explain these curious statistics. Tonnage: Ships are measured in 1000’s of tonnes. Ships were given designations based on tonnage, speed, storage capacity, and a armament’s. Reliability was always important. Really unreliable ships saw much less sea time. Tonnage generally increased over time. For example: a very large warship in 1760 might be 2500 tonnes. That would be a medium sized destroyer or a small frigate today. In 1900, a Battleship would weight between 3000 and 10,000 tonnes. Today, that would be a cruiser at most. At the end of WW2, the first 50,000 tonne aircraft carrier had not been built. Today, they use old 100,000 tonne carriers for breakwaters.
In reading the book, I noticed that the armor plating and armament’s seemed to have a lot to do with a ship’s longevity, along with speed. The armament’s are a curious chess game. A fast ship with little armor plating and armament’s is less likely to survive war than a heavily armed but slow ship. A slow, heavy armored ship may not survive peace.
I noticed in my reading a pattern of armament. In war, bigger is better. Bigger, faster, more Ordinance. Unfortunately, these monsters will rust and die at anchor in peacetime. The trick for a long lived navy ship seems to be a careful balance of armament and functionality. They must be able to survive War, or they won’t be around for the peace. Also they cannot be so heavily armed that there is no room for peacetime, civilian emergencies.
Speed: Speed costs. To put it in perspective. A civilian freighter of 20,000 tonnes of very good design might be capable of twenty knots with a 6,000 horsepower engine. A warship of similar tonnage would have an engine equivalent of perhaps 50,000 to 120,000 horsepower. There are logical reasons for this, but it suffices to say that while in Wartime money is no object. In peace, the cost of running a big heavy hotrod will not be tolerated for very long. Peacetime wants a more economical car/ship.
Political/Philosophical considerations: Perfectly good ships sometimes go out of fashion before they are completely worn out. Government bodies seem to enjoy building ships much more than running them. A stranger phenomenon is one that sees a really good ship mothballed almost immediately after construction because keeping and using it would cause an Arms race. For example: Italy built some of the best ships ever made. They used ship designs 130 years ago that with logical upgrades could still be used today. However, during WW2, some of their best ships were scuttled for fear they would be stolen. One of their ships, used for fifty years was actually purchased from England. England, for example, had one of the best submarines of the allied forces in 1938, it was scraped while almost new six months before the start of WW2. No country ever made serious use of Aircraft carriers except the USA and Japan. And after WW2 it was only the USA. No country except the USA has more than one active Aircraft carrier. Most countries have none.
Conclusion: While technological advancement was certainly a consideration. Seamanship and seaworthiness of ships was strangely low on the priority list. Navy Warships are always political creatures.