Given recent article and speculation on RCN potential Type-212CD batches (if the TKMS contract is negotiated and signed), it makes me wonder if the Type-212CD may have differences between batches? I note the Type-212A had some differences between batches.
I found this recent video on the older Type-212A submarine of interest:
In particular I noted it claimed the initial Type-212A had some issues that had to be fixed - So I surfed a bit to see what changed in the Type-212A, and frankly, I did not find as much detail as I had hoped to find (All my information is from unclassified sources so there could be some speculation/error in the below) :
I read that the Type-212A’s air-independent propulsion (AIP) system relies on nine Siemens BZM 34 (34 kW) Proton Exchange Membrane (PEM) fuel-cell modules operating in parallel, using liquid oxygen and metal hydride hydrogen storage. Operating nine separate modules within a compact hull requires an intricate array of reactant supply lines, coolant circuits, and nitrogen purging valves. This fundamental nine-module BZM 34 architecture was retained across both German and Italian production batches of the Type-212A. I don’t know to what extent the type-212CD will have the same in regards to number of modules.
The Type-212A incorporated a non-magnetic austenitic steel hull, an X-shaped stern rudder configuration for shallow-water operations, integrated flank array sonars, and a water-ram torpedo expulsion system. Internal machinery—including the single MTU diesel generator—was installed on double-resilient raft-mounted platforms to minimize structural noise transmission to passive sensors.
The Type-212A being the first series-produced submarine class equipped with a fuel-cell AIP system, early operational deployments of the Type-212A likely involved an initial learning curve in managing marine fuel-cell logistics and auxiliary balance-of-plant maintenance. I think it is reasonable to infer that ongoing refinement of operational protocols and servicing routines helped establish the system's reliability, supporting confidence in long-term deployment across both of the German and Italian navies.
The German Batch 2 Type-212A boats (U35, U36) differed from Batch 1 (U31–U34) in several respects. Overall length increased from 56.0 m to 57.2 m, with both the sail structure and pressure hull reported longer; German Wikipedia attributes this to new equipment in the sail without specifying which item.
To me, that is a big change. The enlarged sail houses a four-person combat-diver lockout chamber. An optronic mast replaced one of the two periscopes. The enlarged sail was also fitted for (but not with) the Callisto B communications system, a hoistable mast and towed buoy intended to allow communication when submerged; the German Federal Audit Office reports that the Bundeswehr ended the Callisto programme in June 2022 after 19 years of development without a usable result. The boats also received an updated combat system and integrated sonar, with Link 11/16 data-link capability.
Type-212CD:
Building on the operational evolution of the 212A—which Batch 1 displaced ~1,524 tonnes surfaced and ~1,830 tonnes submerged—the Type-212CD (Common Design) represents a structural expansion, displacing ~2,500 tonnes surfaced and a reported ~2,800 tonnes submerged. The 212CD features a distinctive diamond-shaped outer casing designed to reduce active sonar returns. The machinery plant shifts from the 212A's single MTU 396-series diesel to twin MTU 4000-series diesel generators, lithium-ion batteries (originally lead-acid on the Type-212A), and 4th-generation PEM fuel cells in the Type-212CD. For context, while the Type-212A 3rd-generation BZM 34 operated at a fixed 34 kW per module, Siemens’ 4th-generation BZM modules elevate individual output to a higher 40–60 kW while slashing module weight from over 600 kg down to about 200 kg—tripling power density and enabling scalable plant grids between 320 kW and 480 kW within a compact footprint. Traditional optical periscopes in Type-212A are eliminated in favor of non-hull-penetrating digital sensor and communications masts in Type-212CD, featuring an optronic photonics suite supplied by Hensoldt alongside integrated communications masts from L3Harris.
Again the above is from unclassified sources - so it may be inexact.
But it does have me pondering/speculating, that if RCN goes with batch procurement (and does not stop procurement after one batch) what might be the various differences in batches?