Future Australian SSNs entering service must be coordinated with Collins SSKs leaving.
Anonymous on of February 19, 2022, has well argued:
I have been looking at the question of time to construct SSNs, cost and what program must be achieved to minimise the time Collins Class subs must remain in service. This is particularly critical to avoid capability gaps for the RAN. For this purpose I am assuming it is undesirable to keep any Collins SSK in service longer than 40 years from commissioning, even after life extension.
One of the problems in replacement the RAN faces is that the six Collins Class SSKs were built quickly, with a one year "drumbeat" starting in 1990, and an average construction time of 7 years. This means, if we adopt the "40 year rule" that they all need replacement between 2036 (HMAS Collins) and 2043 (HMAS Rankin). Note that in 1995, the ASC shipyard, Adelaide, had the fully or partially completed hulls of all six Collins Class subs present at the one time.
From the little we know about the defunct Attack Class SSK construction program from the ANAO Audit, the intent was to start construction in 2023, with a 2 year "drumbeat" and delivery starting from 2023. With the delays that occurred, the best that could have occurred now was a 2025 start, with delivery commencing from 2035 onwards. This meant the critical 6th Attack SSK, which would replace the last Collins SSK (Rankin) would commission in 2045, when Rankin would be 42 years old. The worst case would be HMAS Sheean, which would not be replaced until 2043, when Sheean would be 43 years old. This ignores any yard capacity constraints, and assumes up to 5 Attack Class hulls could be present in ASC simultaneously.
So had we continued with the Attack Class at the leisurely pace proposed, we would have faced a capability gap risk anyway. This was because we were replacing an SSK class built at a one year drumbeat, with an SSK class to be built at a 2 year drumbeat.
Can we do better? I think the answer is yes. The key is the drumbeat. I have constructed a schedule that assumes the following:
- ASC would build an "AUStute" [Pete comment: Have used "AUStute" rather than "Austute" so it doesn't look like a typo of "Astute".] modified Astute Class SSN, with S9G reactor fitted
- ASC would need to be upgraded to a nuclear engineering standard, taking 3 years to 2025.
- The first AUStute would be laid down in 2026, take 8 years to launch (same as BAE Astute #1)
- AUStutes would be built in batches of 3, with a one year drumbeat between each, but then a gap till the previous boat was launched, assuming ASC can only fit 3 boats at a time, similar to Barrow shipyard in the UK.
- This would give AUStute commission dates of 2034, 3035, 2036, 2041, 2042, 2043, 2047, 2048, and 2049.
- Note that the first batch are assumed to take 8 years each, 7 years for the second, 6 years for the third. This is the same as Electric Boat achieved on Virginia construction, using modular techniques. The same approach should be used for the "AUStutes".
The result is the critical 6th AUStute enters commission in 2043, allowing retirement of Rankin at age 41.
Two other points to note:
1. if we did build RAN SSNs in sequential batches of 3, I see no reason not to build 9 instead of 8. The extra cost and build time would be small once the process is set up.
2. Assuming the AUStute build went from 2026 to 2049, by the time some extra years were added for mid life upgrades of the nine AUStutes, it would be time to start building the next class, nominally in 2056. Hence a continuous build would be achieved.
I have estimated the total program cost in $2022 and outturn $ assuming:
- AUStute cost is BAE Astute cost, converted to Au$, inflated by 1.3 for Australian shipbuilding cost premium (Rand report of 2015), S9G reactor cost added,
- $30 million per annum extra (each) for ANSTO and ARPANSA,
- $558 million of design costs,
- $2.4 billion for ASC upgrade, and $2 billion each for Fleet Base West (2025-2027) and Fleet Base East (2033-2035) upgrades.
The end result is a 2022 cost for nine Australian built Astutes with S9G reactors of $54.6 billion, and an outturn cost of $78.8 billion. This is only Capital Expenditure and regulatory cost, not Operational Expenditure. Also it assumes no differential extra cost to go from the Astute combat system to the US combat system. If that is more, add another $9 billion.
I know this is only speculation, but all is based on public sources. To me, the most critical thing to avoid capability gaps is to start upgrading Fleet Base West and ASC to a nuclear engineering standard ASAP. Sorry for the long post. Not sure how to send you the cost spreadsheet.
Pete Comment
For commercial, legal and political reasons US and UK corporations and governments are unlikely to accept the concept of a UK designed SSN using a US reactor labeled "S9G".
This is why a UK reactor labeled "PWR3", with mixed US S9G and UK Rolls Royce characteristics, seems acceptable.
See https://en.wikipedia.org/wiki/Rolls-Royce_PWR#PWR3
"PWR3 was a new system "based on a US design but using UK reactor technology". The Royal Institution of Naval Architects reported that it was likely that the UK was given access to the US Navy S9G reactor design used in their Virginia-class submarines."
As with a larger version PRW2 going into Vanguards and smaller PWR2 version into Astutes, I suspect a larger version PWR3is going into the Dreadnoughts and smaller version PWR3 into the SSN(Rs) aka SSNRs.