JAKARTA, INDONESIA — With the assistance of a Chinese vessel, Indonesia’s Navy has managed to lift the life raft of the sunken KRI Nanggala-402 submarine amid mounting calls for arms modernisation.
“Vessel Tan Suo Er Hao (Explorer 2) succeeded in lifting the KRI Nanggala’s life raft. We take it as evidence that the ships from our friendly country had carried out their duties,” Commander of the Indonesian Navy’s 2nd Fleet, Rear Admiral Iwan Isnurwanto said in a press briefing on 18 May.
A liferaft is an inflatable boat designed for emergency evacuation in the event disaster strikes aboard a ship. There were two units of liferaft in the Nanggala.
However, the submarine’s main parts — the bow section, hail section, and stern section — have yet to be retrieved.
The Nanggala submarine, which carried 53 people on board at the time, sank in the waters near Bali around a month ago. The incident prompted calls for arms modernisation, considering that the Nanggala was built around 40 years ago.
Indonesia’s Defense Minister Prabowo Subianto stressed there will be a primary weapons system master plan for 25 years, as mandated by President Joko Widodo.
What kind of submarines should a country ideally have, and how many?
The sinking of Nanggala shrank the number of submarines Indonesia’s Navy had from five to four.
Unfortunately, only three out of four have resumed operations, as the Cakra-401 submarine has been undergoing an overhaul at the state-owned shipbuilder PT PAL Indonesia.
This will take place until the end of this year, said the company’s Public Relations Division Head, Utario Esna Putra on 27 Apr.
As an archipelagic country, Indonesia ideally should have between 10 to 12 submarines.
Lawrence Brennan, who is formerly in the United States Navy, told TOC that modern navies need various types of submarines.
He added that there are several factors that determine the need for certain types of submarines, such as geopolitics, cost, availability of budget funds for military construction and repair, among others.
Brennan added that the extreme range at which the nation’s navy will operate submarines, namely how far will they be required to operate from the nation’s home waters, also makes up the criteria that determine what kinds of submarines are needed in a particular operation.
Other than the five to ten largest submarine forces, few navies operate submarines intended to operate in distant waters, he noted.
The availability of distant ports, whether on the nation’s coast or in other nations’ waters, to replenish the operational submarines is also an important element in deciding which types of submarine to deploy.
“Can the navy obtain operational support for its ships in distant waters? Submarines are specialised vessels and probably would require access to ship repair facilities or a submarine tender,” said Brennan.
Military analyst Soleman B. Ponto, in an interview with CNN Indonesia TV on 22 Apr, criticised the modernisation plan for not focusing on buying new weaponry but the secondhand kind instead.
“Do not buy used ships, no, no. You must buy a new one. We have been talking about modernization but the used vessel keeps coming,” he said.
Indonesian lawmaker from the Commission I overseeing foreign policy and defence, Bobby Andhityo Rizaldi said that the government is planning to add new submarines until 2024, CNBC Indonesia reported.
The role of MRO
Prominent military and defence expert Connie Rahakundini Bakrie highlighted the role of maintenance, repair and overhaul (MRO) following the sinking of the Nanggala submarine.
The ideal duration of submarines operational is between 25 and 30 years, while the Nanggala was built in Germany in 1979, Ms Connie said in a virtual discussion on 25 April.
“That’s good that Indonesia can maintain the submarine until 40 years. But that does not mean that we have to wait for 50-60 years to replace our ship,” she stated.
Brennan stressed the vital role of MRO, especially when it comes to submarines as they need special care.
“Special care is required for submarines because of the nature and extent of forces it is subject to during routine operations. They spend most of their time submerged. The hulls of submarines are exposed to great forces as they descend to deep water. The hulls are compressed by increased sea pressure as the submarine dives deeper,” the lecturer explained.
He furthermore elaborated: “Submarines of some nations have two hulls: The outer non-watertight hull and the inner hull which is the pressure hull. It is the pressure hull that maintains structural integrity with the difference between the outside and inside pressures at depth.”
PT PAL Indonesia has built its first submarine the Alugoro-405 in collaboration with South Korea’s Daewoo Shipbuilding and Marine Engineering (DSME).
Before being officially launched, the submarine underwent a Nominal Diving Dept (NDD) in northern Bali waters and it managed to dive up to the depth of 250 meters.