Diagram of HDW 216 arrangement. A 2,000 to 4,000 tonne HDW 218SG submarine (same as or smaller than a HDW 216) would have long range for Asia-Pacific conditions. The design would include greater diesel and battery capacity, AIP and possibly a vertical multi-purpose lock (VMPL) permitting vertical launch capabilities. A horizontal lock, in place of 2 torpedo tubes, might provide be an alternative to a VMPL.
This article follows on from earlier article http://gentleseas.blogspot.com.au/2013/12/singapore-buying-two-hdw-218sg.html announcing Singapore's December 2, 2013, decision to buy two HDW 218SG subs. The HDW 218SG might be a 3000 to 4,000 tonne submarine - for the following reasons:
- HDW is increasingly reliant on its Asia-Pacific customer base. Asia-Pacific customers need longer range submarines and other features such as land attack missile capability. In terms of size this signifies a evolution from below 2,000 tonne HDW 212/214 subs built mainly for European (Baltic, Arctic Ocean, North Atlantic) conditions to a 2,000+ tonne design (see below) for Asia-Pacific (Indian and Pacific Oceans) conditions.
- TKMS-Kockums already has experience in helping to design considerably larger than the European size. That experience is in building the 3,000 tonne Collins Class. TKMS bought Kockums not only to remove Kockums as a competitor to HDW but to utilise Kockums' experience, workforce, technology and design information - including the process of building a larger submarine.
- HDW is developing the 2,000+ to 4,000 tonne, 218 (Asia-Pacific) design not only for Singaporean but for the Australian, Canadian and Indian markets.
- The 218SG build schedule (for launch around 2019 - 2021) coincides with South Korea's building schedule (from 2018) for its planned 3,000 tonne submarine the KSS-III (D-3000). South Korean subs to date have heavily relied on HDW 209 (KSS-I) and HDW 214 (KSS-II) designs. This pattern suggests that the 3,000 KSS-III will also be supported by HDW design work despite South Korea's claims of a wholly "indigenous" KSS-III design.
- A 2,000 to 4,000 tonne submarine could incorporate heavier battery, increased diesel oil and large AIP capacity for increased Asia-Pacific range requirements. Advice here is "the 218SG will have 240-320kw PEM fuel cell AIP (offering 22-30 days at 5 kts)". Heavier batteries can also allow longer range submerged operation with higher discretion (non-snorkel use) rates against (mainly) Chinese sensor platforms.
- A 2,000 to 4,000 tonne submarine would also have the range to permit Singaporean use of refuelling-replenishment bases belonging to its US and Australian allies. Such bases include Diego Garcia, Guam, Pearl Harbor and Rockingham (Australia).
The HDW 218SG is most probably designed for long-range Asia-Pacific conditions, all requiring a 2,000 - 4,000 tonne displacement. SG signifies a subset of HDW 218 customized for Singaporean conditions - including air-conditioning for tropical weather, hull-anechoic coating optimized for warmer sea use and a Singaporean-specialized combat system. The HDW 218SG probably represents HDW's latest export submarine design for launch around 2018 and first delivery around 2020.
The designation 218 (neither 214 nor 216) provides uncertainty over the 218's features and weight. This uncertainty provides advantages for Singapore's national security and commercial-competitive secrecy for HDW. HDW would also wish to avoid any mid-build headlines like those experienced by Navantia over the S-80 - see the S-80's weight problems at http://gentleseas.blogspot.com.au/2012/06/australias-future-submarine-selection-s.html .
By not specifying the 218's weight this also permits flexibility in balancing desirable features, within Singapore's expected tonnage parametres, without politicized assumptions. Development of a 218SG somewhere in the 2,000 - 4,000 weight range also may have implications for HDW's likely tendering for Australia's future submarine SEA 1000 project.