Contact Us   |    Join   |    Donate


Lajos F. Szaszdi last year obtained his Ph.D. in World Politics at the Catholic University of America. His father is of Hungarian descent and his mother from Ecuador, both of whom are historians. Born in Puerto Rico, Dr. Szaszdi is a student of sea power and naval history, and of submarines in particular. He has been attending the League’s annual symposiums since 1995.

This study will consider the potential of the Republic of Croatia as a builder of modem diesel-electric submarines, and thus as a possible source of conventional submarines for Taiwan. As a background to the case, on April 24, 2001, President George W. Bush pledged U.S. assistance to Taiwan in the acquisition of eight new diesel-electric submarines (SSK). 1 However, due largely to the threat of commercial reprisals by China, the main Western builders
of conventional submarines in the international arms market; that is, Germany, France and Spain, Sweden, and the Netherlands have all refused to make SSKs for the Taiwanese.2 Presumably, Italy would have adopted the same policy posture. Another major builder of conventional submarines, Russia, would not sell its underwater warships to the island-state because of its strategic partnership with China, and since Moscow is an important supplier of submarines and submarine technology to the Chinese People’s Liberation Army/Navy (PLAN).

The building of conventional submarines in the U.S. for Taiwan is riddled with difficulties. According to Wendell Minnick of Jane’s Defence Weeklv, writing in the summer of 2005: “US defence officials told JDW that the DoD is increasingly reluctant to provide SSKs due to opposition within the US Navy and the simple fact that the US no longer builds that type of submarine. ‘The costs of such a project would be staggering,’ said one US defence official.”3 More recently, Taiwan’s accusations that the U.S. Navy’s opposition to domestic construction in the U.S. of conventional submarines is preventing the program from materializing have again resurfaced. This claim was confirmed by an informed U.S. source that told JDW:

Bottom line is that the initiation of the Taiwan submarine programme has tremendous implications for the US Navy:
once it gets going, they will not be able to resist the alreadyexisting pressure to integrate diesels with AIP (air independent propulsion) into the navy inventory for littoral warfare. So they have been artful in making it seem like they have supported the President’s policy, yet purposely making it such a bitter pill to shallow (sic) – what I call “death by bureaucracy.”

The estimated cost of the program to construct the 8 submarines in the U.S. is indeed staggering. According to the U.S. Navy’s Independent Cost Estimate (ICE), it would be between $9.4 billion and $11.7 billion, of which $5.3 billion would be the cost to build the vessels. Reasons claimed by members of the Taiwanese legislature for its repeated rejection of the Special Budget proposed to acquire the SS Ks are the huge expenses of the project and the idea of funding submarines whose design has not been chosen yet.’

It has been suggested also that the U.S. could build conventional submarines based on its last diesel-electric design of the Barbel class, developed in the mid I 950s. 6 U.S.-made conventional submarines possibly would have been built at Ingalls Shipbuilding in Pascagoula, Mississippi, as this shipyard was chosen to build for Egypt at least 2 submarines of the Dutch Moray 1400 class.7 However, the construction of the Egyptian submarines did not materialize after apparently being made contingent on the building of the 8 SSKs for Taiwan. 8 The building of diesel-electric submarines for Egypt and Taiwan at Ingalls Shipbuilding would have made this shipyard a serious competitor to the last two remaining yards building nuclear-powered submarines in the United States: Electric
Boat in Groton, Connecticut, and Newport News in Virginia. The production of conventional submarines for export could open the door for future orders of this type of vessel for the U.S. Navy, under
the claim that since SSKs are less expensive to build and operate than nuclear-powered attack submarines (SSN), more conventional submarines can be acquired for the price of a nuclear-powered vessel, thus threatening the number of future SSNs that could be procured and produced at Groton and Newport News. Such a scenario could lead to the loss of the underwater naval supremacy currently enjoyed by the U.S. Navy thanks to its all nuclear-powered
submarine fleet. It could also lead to the loss of jobs in Newport News and in Groton, if projected numbers of SSNs that could have been built at these two yards are cut hack in favor of production elsewhere in the U.S. of conventional submarines for the Navy.

With regard to the option of building diesel-electric submarines in Taiwan, Commodore Saunders of the Royal Navy wrote that “this would present a considerable industrial challenge and almost certainly involve some form of technology transfer.” Indeed, the design and construction costs of SSKs in Formosa would be immense.

Thus, the main builders of diesel-electric submarines in the world are unwilling to construct such type of combat vessels for Taiwan. In addition, it would be very costly to resurrect in the U.S. its erstwhile expertise and capability to build conventional submarines, as it would be for Taiwan to create from scratch this genre of
shipbuilding industry. Moreover, there is strong opposition inside the Navy, and probably in Congress also, for the idea of constructing diesel-electric submarines in the U.S. One consideration that remains
unchanged, however, is the fact that Taiwan needs at least the proposed 8 SSKs to be able to confront with some degree of success, in case of conflict with its western neighbor, the current numerical superiority in submarines and surface combatants of China, and the challenges that in the future will be posed by a more capable and
modem PLAN submarine fleet. Moreover, a larger Taiwanese Submarine Force of 8 new submarines plus the two it already has could bear some of the brunt of the fighting in the shallower waters of the Taiwan Straits, thus perhaps reducing the number of U.S. Navy units (and consequently freeing them for other missions) that
would otherwise be required to defend the island-state. Croatia is thus proposed as an alternative source of conventional submarines for Taiwan, provided, of course, that the Croatian government would be willing to participate in such a plan.

Croatia has a long tradition in naval shipbuilding firmly established during the times of Austria-Hungary, constructing then in addition to surface combatants, submarines for the Austro-Hungarian Navy at the shipyards of Pola (Pu la) and Fiume (Rijeka). After the Second World War, design and construction of diesel-electric
submarines for the Yugoslav Navy resumed in Croatia first at Pula, and then at Split (Spalato) for the last twenty-five years or so of Yugoslavia.

Brodarski Institute

The Brodarski Institute of Zagreb is Croatia’s foremost research and development organization, which, according to Naval Forces, “remains holder of technical developments of naval vessels and ubmarines.” According to the institute’s website:

Our teams design vessels with a high standard of interior
design, develop maneuvering systems and test them in inhouse hydrodynamic laboratories or in full scale: … special purpose vessels (patrol craft, naval vessels and submarines).

Our specialists have long-standing experience in development, design and manufacture of underwater technology systems and equipment (underwater vehicles, integrate underwater sensors, control and guiding systems).12
Brodarski Institute designed the submarines of the Heroj and Sava classes and the midget submarines (SSM) of the Una and Modified Una classes. 13

Brodosplit Shipyard

The Brodosplit Naval & Special Vessel Shipyard or BrodosplitBSO is located at the Adriatic port of Split on the coast of Dalmatia, and it is a subsidiary of Brodosplit Shipyard, which belongs to the Croatian Shipbuilding Corporation. The Croatian state in turn controls a majority stake in the Croatian Shipbuilding Corporation.14 According to the web page ofBrodosplit-BSO:

Over three decades of tradition in building sophisticated warships, submarines and special naval vessels gave to the Shipyard an outstanding position among the Croatian shipyards and among very few of such specialized shipyards at the international level.

The great advantage of Shipyard is shipway hall for constructing ships up to 60 m length. BRODOSPLIT-BSO, d.o.o. is comprehensively equipped to design, construct, equip and test large scale of vessels and constructions represented by the following programs:

Naval program: conventional submarines, midget submarines, frigates, patrol boats, logistic support vessels …

Having experience with various Navies, specially with Croatian Navy expert teams of Shipyard are ready to give full
after delivery support for maintenance, over-haul, training, marine support equipment, logistics ….

High strength steel construction program: off-shore structures, tanks for LPG [Liquified Petroleum Gas, Pressurized Gas], pipelines … New projects: being experts in submarine technology …. 15 It would appear from this description of capabilities that, since the collapse of Yugoslavia, Brodosplit-BSO has retained the knowhow and maintained the infrastructure to design and build dieselelectric submarines. Tellingly, its advertising of the ability to construct with high strength steel would suggest that this shipyard can build pressure hulls for submarines, as when Brodosplit built conventional submarines for the Yugoslav Navy.

The last two diesel-electric submarines built for Yugoslavia, of the Sava class, were constructed in Brodosplit, with the SAVA entering service in 1978 and the ORA VA in 1982.’6 The pressure hull of the Sava class was reportedly made of steel with a strength of 56 kg/cm~ that enabled the submarines to reach a diving depth limit
of 300 meters. It was also reported that the outer hull of SAVA and ORA VA was made of glass-reinforced plastic.17 With a crew of between 27 and 35, the SA VA class was said to enjoy a “high degree of automation.”18 It had a displacement of 770 tons surfaced and of 964 tons submerged, an underwater speed of 16 kts, a length of 55.8
meters and a beam of 7.2 meters, and was armed with six 21 inch (533 mm) torpedo tubes (TT) in the bow. The Sava class submarines each carried 10 torpedoes, including Swedish Tp 61 wire-guided torpedoes, or up to 20 sea mines.’

Sava’s had a length-to-beam ratio of 7.75, which compares favorably to the length/beam ratio of 10 of the Chinese Ming class of diesel-electric submarines, of 8.9 of the Song class or of 9.7 of the future Chinese Project 093 nuclear-powered attack submarine class. 20 A submarine with a shorter length/beam ratio might be more maneuverable than another with a greater ratio, particularly in the shallower depths of littoral waters.

The Sava class was preceded by the 3 diesel-electric submarines of the Heroj class, of which the second, named Junak, was constructed in Brodosplit, entering service in 1969. The Heroj class submarines had a displacement of 1,068 tons standard, 1, 170 tons surfaced and 1,350 tons submerged, a length of 64.0 meters and a width of 7.2 meters.21 Based on these data, it can be inferred that the shipbuilding hall of Brodosplit-BSO can build a ship 64 meters long, slightly more than the reported limit of 60 meters in length for
vessels constructed there as advertised for this shipyard in the Croatian Shipbuilding Corporation’s website.

Before the collapse of Yugoslavia in 1991, an improved version of the Sava class was reportedly under construction, allegedly since 1986 until the cancellation of the program. Identified as the Lora class, the new SSK would have possessed a displacement of 900 tons and would have had the capability of deploying to the Mediterranean Sea.

The SS 580 Barbel’s Design

As suggested above, the proposed 8 SSKs for Taiwan can be based on the design of the last class of diesel-electric submarines built for the U.S. Navy, the Barbel class, and these could be built in Brodosplit-SBO. The hull of the BARBEL was built following the innovative teardrop design of the experimental submarine ALBACORE. Commissioned in 1959, it could reach an underwater speed of 25 lets, in great measure thanks to the streamlined design of its teardrop hull. 23 BARBEL had a standard displacement of 1,740 tons, 2, 146 tons surfaced and 2,640 tons submerged. It had a length of 66.75 meters, a beam of 8.84 meters, and was armed with six 2lin TT. ~ The submarine ‘s successful design was adopted by the Netherlands and Japan,2 ‘ with the Dutch Zwaardvis class of SSK.s having been inspired by it,26 and according to naval analyst Norman Friedman, “modem Japanese submarines … are essentially Barbels.”21 So are also the two Dutch·built SSKs of Taiwan of the Sea Dragon or Hai Lung class; according to Combat Fleets of the World, these submarines’ “design … is based closely on that of the Dutch Zwaardvis class.”28 There is also a close resemblance in tenns of tonnage, with HAI LUNG’s maximum submerged displacement being 2,657 tons compared to the 2,640 tons of BARBEL ‘s submerged displacement. Moreover, HAI LUNG has a length of66.92 meters and a beam of 8.40 meters compared to the length of 66.75 meters and beam of8.84 meters ofBARBEL.29 Thus, the length-tobeam ratio of HAI LUNG is 7.96, compared to that of 7.55 of BARBEL. As a matter for comparison, SAVA submarines had a length/beam ratio of 7. 75, while the length/beam ratio of the proposed Dutch design for the Moray 1400 type of diesel-electric submarines would be 8.95 in its basic version. The dimensions of the basic Moray 1400 are 57.3 meters in length and 6.4 meters of beam, with a displacement of 1,430 tons surfaced and 1,595 tons submerged.30


Diesel-electric submarines built in Croatia, funded by Foreign Military Sales (FMS), can be fitted with U.S. made equipment such as sensors, weapons, the combat management system, and propulsion plant. The venture with the Croatian shipyard would have a U.S. defense corporation as major systems integrator for the submarines,
having the potential to become as successful as the partnership between Lockheed-Martin and the Spanish shipyard lzar (now Navantia) for the building of AEGIS-type frigates and corvettes. This partnership has enabled Lockheed Martin to enter successfully to the very competitive European market for guided-missile frigates. Likewise, a partnership with the Croatian shipbuilder could allow a U.S. defense corporation selected to be the submarines’ main systems integrator entry into the exclusive international market of conventional submarines, dominated now by Gennany, FranceSpain, Russia, and Sweden (Swedish submarine builder Kockums is owned by Howaldtswerke Deutsche Werft of the new group ThyssenKrupp Marine Systems31 ).

For example, the submarines for Taiwan can be equipped with the SUBICS 900 fully integrated sensor, command and weapons control system produced by Lockheed Martin. The SUB JCS 900 was also chosen for the diesel-electric submarines that were to have been built by Ingalls Shipbuilding for Egypt. Lockheed Martin Naval Electronics and Surveillance Systems would have been the main systems integrator for the U.S. built Egyptian submarines.32 The
submarines for Taiwan can be armed with the Mk 48 Mod 6 ADCAP torpedo by Raytheon, and can carry the Improved SubmarineLaunched Mobile Mine (ISLMM), also produced by Raytheon, and which were to be one of the weapon systems carried by Collins class of Australian submarines.33 Production of conventional submarines in Croatia, with a U.S. contractor as main systems integrator, could lead after a successful Taiwanese order to furtherorders from friends
and allies of the U.S., with Egypt being one potential customer.

Midget Submarines

RH-ALAN-Brodosplit in Split, Croatia, built the Una class of midget submarines for the Yugoslav Navy, having developed an improved version for the Croatian Navy, the VELEBIT of the Modified Una class (M-1000 class). With 88 tons surfaced and 99 tons submerged, VELEBIT has a length of 20.92 meters and a beam of 2.70 meters, with a length-to-beam ratio of 7.74. It has an endurance of 7 days, and a range of 500 nautical miles at 8 kts with
snorkel and of 135 nm at 3 kts submerged (Brodarski Institute gives the vessel a range and autonomy of 250 nm at 4 kts ). It can operate normally at a depth of 105 meters, with a test depth of 120 meters, and an approximate crush depth of 182 meters. VELEBJT can technically remain submerged for up to 96 hours, and it has an Xplane control surface at the stem that enables the midget submarine to remain at the bottom in a more stable fashion. It has a lock in/lock out chamber and can carry 6 swimmers in addition to the crew of 4-6. The vessel can be armed with 2 torpedoes or carry 4 heavy seabed mines or 6 500 kg seabed mines. The SSM can also take externally
4 Swimmer Delivery Vehicles (SDV) with limpet mines.34 In addition, Croatia is planning a bigger design of midget submarines, with 120 tons displacement, and which will be armed with four 21 in TT and could carry 4 SDVs.

In addition to the 8 diesel-electric submarines, it is proposed that Taiwan could acquire midget submarines for the defense of the coastal waters of Fonnosa and of its various insular territories. The range of the Croatian SS Ms, for instance, could enable such boats to reach on their own the islands of Quemoy and Matsu. Midget submarines could be ideal weapons against amphibious warfare ships participating in an invasion of Taiwan’s island dependencies. It must also be mentioned that overall, the shallow waters of the Taiwan Straits are more suitable for not-too-large submarines to operate, with depths ranging from 13 to 3 7 meters in waters close to Formosa’s western coastline, from 11 to 38 meters in the area of the Taiwan Banks, from 129 to 172 meters in the Strait of Pescadores separating Pescadores Islands from Fonnosa, and from 21 to 96 meters in the Taiwan Straits proper. South of Formosa, the seabed plunges to deeper waters as on the eastern side of the island-state.


Some incentives for the Croatian government to participate in the building program of 8 submarines for Taiwan could be:
I. Croatia could acquire (if interested) 2 or 3 diesel-electric
submarines of the same type as the ones sold to Taiwan, paid by
2. Participation in the project will create jobs in Croatia.
3. It would restart Croatia’s conventional submarine industry, and
in cooperation with a U.S. defense corporation could become a
major competitor in the international diesel-electric submarines
market by building submarines for U.S. allies worldwide.
4. The United States could back Croatia’s early entry into NATO
and give diplomatic support in other spheres sensitive to Croatia.

Naval Submarine League

© 2022 Naval Submarine League