Israel's announcement that it plans to buy three new (and larger) submarines will maintain its desired level of six submarines.
See more details in this article https://www.yahoo.com/news/israel-seeking-three-submarines-germany-report-094813311.html .
To maintain Israel's fleet of 6 submarines Israel will introduce one (possibly 3,000 tonne) Dolphin 3 when retiring each of its aging-by-then Dolphin 1s. The TKMS Dolphin 1s were commissioned in 1999 and later, non-AIP and derived from TKMS Type 209s. Note - to maintain the six submarine fleet Israel also has three Type 214 derived Dolphin 2s (with AIP). See curret Dolphin numbers here.
The most important mission of Israel's Dolphin submarine fleet is as nuclear armed second strike platforms. Iran is on top of the hit list.
The first of the three new submarines is due to be bought by, or delivered to, Israel in 2027. If larger they could be of the 3,000 tonne class that TKMS is designing with South Korea. Israel's current larger subs (the Dolphin 2s) are just 2,000 tonnes (surfaced).
At a very low "combined price of 1.2 billion euros ($1.3 billion) [for the three Dolphin 3s]" it appears Germany is continuing the tradition of heavily subsidizing submarine sales to Israel. This is a German post Holocaust "reparations" policy.
A 3,000 tonne sub could:
- have greater range/endurance time on station
- accommodate larger, longer range, nuclear tipped land attack missiles (probably fired
horizontally from the 650mm (or larger)) torpedo tubes.
- a more powerful combat system with more potent sensors, including passive sonars.
- longer time totally submerged
- accommodate more crew to minimise exhaustion and
- can accomodate larger/longer range/heavier warhead missiles (fired vertically or horizontally).