Tyloe Mon May 18, 2015 5:11 pm
They're both likely competing proposals, along with other concept designs shown before, aimed for a future destroyer program like the Leader-class project. But for now none of the designs seem to have officially been chosen. And it'll be a while until the Navy starts the program since the current priority for surface ship acquisition is getting the new frigates constructed and commissioned for the next 5 years or so. This mean there might be more design proposals down the line, if there are specific requirements given such as its potential mission suite, tonnage, dimension, or cost limit.
If the VMF has already started examining designs for the Leader program then a design like Project 21956 proposal seems like a realistic option to construct 10+ units from, and a fitting successor to the Udoloy, Sov destroyers and Slava cruisers. At 9000+ tonnes its very likely a less burden on spending and can easily allow intergration of modern systems from the Gorshkov and Grigorovich frigate classes. By the time the destroyer program starts, the new frigate's systems and technologies will be matured.
In comparison, a class like 23560 will likely lead to a very expensive program and you might be able to afford two 9000 ton destroyers for the price of one cruiser or heavy destroyer. Technologies and systems to support 23560 likely needs extensive time for testing as well. Unless there's another long term program for a Kirov successor, a 15-18000 ton destroyer design can only be built for a few units and not a sufficient number to succeed the older vessels. The Zumwalt program and the cancellation of the DD-21 is an example how running costs can bite on such over-demanding naval projects. The U.S wanted the DD-21 to replace the Tico cruisers and the Zumwalt to replace the Arleigh Burkes, but ultimately those plans ended until the construction of only 3 units of Zumwalt destroyers.