MILDEN

The boat that ends the German license — MILDEN ("National Submarine") is Turkey's first indigenously designed attack submarine: a ~2,700-tonne, methanol-reformer AIP boat whose first weld was laid at Gölcük Naval Shipyard on 2 January 2025 and whose lead unit was named Atılay — after the first submarine ever built in Turkey — that December. Every current Turkish submarine is a German design built under license; the Atılay class is built to make that sentence past tense. Nothing has been launched, nothing tested at sea: this is a sovereignty program in the block-assembly stage, with delivery promised for the first half of the 2030s.

Overview

MİLDEN (Milli Denizaltı) is the underwater apex of Turkey's naval-sovereignty pyramid — announced the same day, 2 January 2025, as first steel for the MUGEM aircraft carrier and TF-2000 destroyer, and by the Navy's own framing the program that puts Turkey "among the ten countries in the world capable of designing and constructing their own submarines." The design (all figures Turkish official claims) is a ~2,700-tonne surfaced, 80-plus-meter diesel-electric attack boat — substantially larger than the ~1,850-tonne German-designed Reis class (Type 214TN) it follows — with an indigenous air-independent propulsion system of six PEM fuel-cell modules fed by a methanol reformer plus lithium-ion batteries, a crew of an estimated 40–50 through automation, and greater diving depth and weapons load than anything Turkey now operates. Armament is the national catalog: eight 533 mm tubes for Roketsan's Akya heavyweight torpedo, the sub-launched Atmaca anti-ship missile and, later, the Gezgin land-attack cruise missile, under an Aselsan sonar suite and Havelsan combat-management architecture, with a non-penetrating optronic mast in place of a periscope. The strategic purpose is explicit: the six Reis-class boats building at Gölcük under HDW/TKMS license were declared Turkey's last submarine imports, and MILDEN — plus the nuclear-powered boat the Navy openly names as the step after it — is what comes next. The discipline this entry keeps: it is a program of welds, ceremonies and claims, with the S-80's decade of sovereign-submarine pain as the standing cautionary tale.

Development

The program traces to the Navy's design offices around 2010–2012 (sources diverge on the start year), maturing through a 2017 STM concept (the 1,740-tonne x-TS1700 shown at IDEF) that the Navy's own larger design superseded, to concept-design approval in January 2022, per Naval News — whose August 2022 interview at Gölcük fixed the public parameters: ~2,700 tonnes, over 80 meters, AIP, construction from 2025, delivery in the early 2030s. The milestones since have come as a staged — and in Turkish messaging, somewhat blurred — sequence: a test block reportedly in fabrication from late 2024; the first-weld ceremony on 2 January 2025 at Gölcük Naval Shipyard (the MUGEM carrier and TF-2000 destroyer cut steel at Istanbul Naval Shipyard the same day), per Naval News and Shephard; confirmation in the MoD's December 2025 briefing that first submarine blocks were in assembly — the industrial phase, per Militarnyi; and the keel-laying and naming of the lead boat as Atılay that same month, per TURDEF — recycling the name of Turkey's first home-built submarine of the 1930s, and of the retiring Type 209 class. In May 2025 the Navy chief confirmed export intent and framed MILDEN as the "crucial step towards constructing nuclear-powered submarines"; by April 2026 the state firm ASFAT was pitching an Atılay-class model at DSA in Kuala Lumpur, per Army Recognition. Official delivery target: the first half of the 2030s.

🔒 The rest of the MILDEN file is for BattlePolicy Pro members. Stop here and you miss the part that actually matters: the methanol-reformer AIP bet, the Reis-class bridge that made it possible, how it stacks up against the S-80, Hai Kun and KSS-III sovereign-submarine programs, the complete specifications table, and our analysts' program and assessment notes. Unlock the full file with BattlePolicy Pro →