Russia has been trying, since the late 1990s, to build replacements for Cold War era warships. Many of these have reached the end of their useful lives and many of them, while still listed as in service, rarely, if ever, seem to leave port. Russian admirals have been aware of the fact that they won't have much of a navy by the 2020s unless these older ships are replaced. The problem is that the older ships cannot be refurbished or upgraded because that would cost more than buying new ones, These older ships are not just falling apart, but because there was not any money available right after the Soviet Union dissolved in 1991, there were few repairs and no upgrades during the 1990s.
The Russian parliament finally came up with more money after 2000 to build enough surface ships to maintain a respectable fleet. But there's the other problem. Most of Russia's warship building capability (experience and kills) disappeared during 1991. Before 2014 the government thought it had a solution and that was to make a deal with France to import modern warship building techniques, by purchasing two Mistral amphibious assault ship/helicopter carriers, and the right to build two more in Russian shipyards. During that process, Russian shipbuilders would learn how it's done in the West. Since the late 1990s, most of the Russian construction effort went into finishing a few subs and building some surface ships for export. Even these subs had serious construction problems. Mainly it was quality control and the navy refused to accept ships, especially subs that could not pass sea trials. Apparently, the ship yards were ordered to put all their efforts into the subs and eventually some of these limped into service. But the deal to import French shipbuilding techniques disappeared when Russia invaded Ukraine in 2014. France refunded the billion dollars paid for the two Mistrals (and later sold them to Egypt) leaving the Russians on their own.
Now the Russian navy is in desperate shape. The latest example of how this is working out can be seen in the continuing delays getting the new class of 4,500 ton frigates (the Gorshkov class or "Project 22350") into service. Construction on these began in 2006 but by 2010 only one had been launched and it was still only half complete. The navy wanted twenty Gorshkovs to replace the Cold War era Sovremenny class destroyers and Burevestnik class frigates. The government has only promised money for twelve Gorshkov sand has since raised that to fifteen. But so far the first Gorshkov has not passed sea trials. This ship was commissioned in 2017 but could not enter service until it passed the sea trials. So far the Gorshkov has not done so. The latest delay is the failure of the anti-aircraft missile system to function properly. There are also problems with the engines. The builder says all will be ready by July. A second Gorshkov was launched in 2014 and is to be ready for sea trials in 2018. A third Gorshkov is under construction but the launch date is unknown because another side effect of the Ukraine invasion was Ukraine refusing to supply any more naval turbines. Russia said it was having a Russian firm begin construction but that is behind schedule and now it looks like no more Gorshkovs (aside from the first two) will be available for completion until the early 2020s.
The Gorshkov's are armed with a 130mm gun, two Kashtan autocannon systems for missile defense, 8 Yakhont 3M55 or PJ-10 BrahMos anti-ship missiles (both are three ton supersonic missiles, with the BrahMos being an advanced version of Yakhont developed in cooperation with India), a launcher for 24 Uragan 1 (SA-N-12) anti-aircraft missiles (30 kilometers range, 70 kg/154 pound warhead), four 533mm (21 inch) torpedo tubes, four RPK-9 (SS-N-29) anti-submarine rockets and a helicopter. These ships require a crew of 210 sailors and will have the latest electronics the Russians have available for anti-air and anti-submarine work. These ships cost about $400 million each and will replace larger ships like the 7,900 ton Sovremenny class destroyers. These older, larger, ships, were designed for high seas operations far from Russian shores. The new fleet will be a return to the traditional Russian navy job of defending coastal waters. Even accomplishing that mission is in doubt if Russian cannot get its shipyards up to speed. Russia has been able to build some new corvettes but these are smaller and much less capable ships than the Gorshkovs.
The Gorshkovs are not an isolated example. The same problems have been encountered with the Su-57 stealth fighter, the radical new T-14 tank, the new Borei SSBN and the Bulava ballistic missile it uses. In general Russian defense, industries continue to have problems developing new engines. The Russian space program is having similar problems with its rockets. The list goes on and on. Russia plays down all these problems but the net result is they have very little locally produced stuff to replace their Cold War designs. Worse, China is now producing improved and more reliable versions of those Cold War era weapons, along with new Western tech (like large, missile armed UAVs) that Russia cannot master.