See official "Details" about the LOTE.
Following Collins LOTE Part 1: Budgeted. Saab, LM & MTU of April 22, 2024 what replacements and upgrades are needed for the LOTE?
If the 6 Collins were Life of Type Extended ("LOTEed") from 2026 at 2 year intervals the first 2 would probably retire in the 2030s with the remaining 4 soldiering on through to the mid 2040s.
Main items I think worth replacing or upgrading are:
- replacing the Collins’ 3 x Garden Island-Hedemora DIESELS. These are probably no longer in production. They are relatively compact permitting all 3 to sit parallel - saving space. However they are probably unreliable (in the saltier waters of the Indo-Pacific) - so probably need a high level of expensive deep maintenance. The 3 might be replaceable by 2 more powerful Kawasaki 12Ｖ 25/25 SB-type or 2 MTU 4000s submarine diesels (that for more than decade have become highly mature for Indo-Pacific conditions). So, as replacements, 2 x MTU 4000 submarine diesels for each Collins might be reasonable.
- maybe new Generators to replace the 3 × Jeumont-Schneider generators with 2
- strengthening the pressure hulls, as the need for extensive hull cutting to replace/overhaul the Hedemora Diesels has weakened the pressure hulls, reducing safe diving depth.
- many combat system items: ie. photonic aka optronic masts replacing existing periscopes, latest technology work stations, new servers, new hardware and software to torpedo tube launch Australia's new Tomahawk anti-ship and land attack missiles.
- many worn mechanical moving parts and seals need replacing
- electricals that have water damage need replacing, as they can corrode, then fuse, then catch fire.
- Lithium-ion Batteries (LIBs) perhaps cannot be retrofitted into the Collins. The Collins' balance/buoyancy, electrical and electronic fittings and components have been built specifically around Lead-acid Batteries (LABs).
Timings
I'm not convinced the Virginias will be delivered to Australia in the 2030s as the US will lack enough Virginias even for the USN. See pages 19 to 20 of this CRS Report. US Virginia production might reach "shareable levels" (phrase coined here first) after the US' new Columbia-class SSBNs "are expected to be completed"in 2042.
Even LOTEed Collins will only last till the mid 2040s when their pressure hulls become too metal fatigued due to contraction-expansion cycles.
So Australia may
increasing need to rely on AUKUS Pillar 2 generated Ghost Shark XLUUVs from the
early 2030s to do everything except fire torpedoes and missiles.
Virginias and/or SSN-AUKUS's might be available to the RAN from the mid-late 2040s.