As for the submarine issue:
First of all a translated quote from official Brazilian Ministry of Defense website:
...2) the chosen model will be equipped with Advanced system of propulsion, as the AlP, in the case of the submarines German?
Reply: The Navy decided for proieto of IKL 214 without AIP. The reasons that had led to such decision are of essentially logistic order. The spite of some undeniable operational advantages presented by the system, that allows to the submerged navigation low the speed, for about ten days, without necessity of atmospheric air, the MB very considsiderou high custos' of attainment, operation and maintenance of this system. taking the one that the reason cost/benefit was not justified.
But to illustrate, the system demand, to each recharge, fifteen tons of liquid oxygen and about two tons hydrogen to 99.9999% of pureness, in the gaseous state, represents. for this gas, volume equivalent the eight truck-tank. Beyond the natural difficulty in the attainment. it would have problems for the transport until the submarine, rank that the hydrogen is considered dangerous load. Also; to transfer the gases of I propagate it of supply for edge; one is necessary
Infrastructure for the recharge of the blisters of storage of submarinoj what it would make impracticable the restocking is of Rio De Janeiro, in the hypothesis to have availability of these gases in other ports. Finally, a sailed nautical mile with AIP costs the equivalent US$ 43 (forty and three dollar); with diesel, US$ 6 (six dollar)...
http://www.defesanet.com.br/zz/mb_u214.htm
Forgive the google translation, but I think the main point of the text is understandable:
Brazilian Navy concluded that Hydrogen Fuel Cell Air Independent Propulsion (AIP) system is difficult to maintain, store and operate.
The most striking information is the comparison of operational costs of fuel cell and diesel: USD43 for fuel cell per nm vs USD6 for diesel per nm. More than 7 times..
Type 212 and 214 class of boat use PEM (Proton Exchange Membrane) type fuel cells developed by HDW of Germany. In this systems, electricity is produced by electrochemical processes, unlike other systems like MESMA.
PEM system require oxygen and hydrogen stored in seperate tanks in the boat. One fuel cell produces 0.7V electricity and the byproduct of the process is pure water. In fact, PEM fuel cell is something like an anti-battery.
So the advantages and disadvantages of the system are:
Pro's
- Whole process is chemical, thus less (or no) noisy than other AIP technologies
- Fuell cells and catalysers require less maintenance
- By-product is only water
Con's
- Hydrogen, which is a very dangerous and flammable gas, is have to be stored in the submarine
- Energy output of one cell is very low, so a huge number of cells need to be carried = Effectivity is low.
- Catalysers are made of platinum, which is negatively affected from carbonmonoxide, thus losing effectivity very quickly during operation. This is one of the very main reasons of enourmously high operating costs of PEM Fuel Cell, which has still not been 100% effectively solved. That's why PEM Fuel Cell technology is seen by many officials as not fully matured.
On the other hand, PEM Fuel Cell is the most commercially succesful AIP system. Although it cannot give diesel electric boats the range and submerged endurance capabilities close to SSN's, it offers good cruise time while submerged. Why one navy may need longer submerged cruise duration for its submarines?
1. It has a limited number of submarines or want to reduce the submarine fleet in the near future,
2. It has a very large area to protect (for both naval assets and sea trade), dictating much longer patrol missions,
3. The potential enemy has good ASW assets, forcing the submarines dive much longer.
4. ?
Now, let's take a break and have a look at Greece's current submarine fleet:
Type 209 / 1100 Glavkos Class
- 4 boats (S110 Glavkos, S111 Nereus, S112 Triton, S113 Proteus) (received limited upgrade under "Neptune I" programme, 1993 - 2000)
- Entered service 1971 - 1972
- Displacement (surfaced/dived): 1,125t / 1,235t
- 4 x MTU 12V 493 AZ80 GA31L diesels (2,400hp); 4 x Siemens alternators (2,280hp); 1 x Siemens electric motor (4,600hp)
- Speed (surfaced/dived): 11kt/21.5kt
- Max depth: 250m (crushing depth) (probably operational max depth is max200m due to aging hull)
- SSM: 4 x UGM-84 Harpoon
- Torpedoes: 14 x Atlas Elektronik SUT Mod0 (8 x 533mm tubes)
- Sonar: Atlas Elektronik CSU 83-90; Atlas Elektronik PRS 3-4
- ESM: Argo AR-700-S5
- C3: Lockheed Martin Tactical Defense System-GETEN Kanaris; Link 11
- Periscope: Carl Zeiss Optronik SERO 40 STAB
- 4 boats (S116 Poseidon, S117 Amphitrite, S118 Okeanos, S119 Pontos) (3 boats will receive major upgrade dubbed "Neptune II", each boat will be in refit for about 3 years)
- Entered service 1979 - 1980
- Displacement (surfaced/dived): 1,200t / 1,285t
- 4 x MTU 12V 493 AZ80 GA31L diesels (2,400hp); 4 x Siemens alternators (2,280hp); 1 x Siemens electric motor (4,600hp) (the same machinery as Glavkos class; will receive PEM fuel cells after Neptune II)
- Speed (surfaced/dived): 11kt/21.5kt (the same as Glavkos class, probably will slightly cesrease after Neptune II, due to small increase in length, displacement)
- Max depth: 250m (crushing depth)
- SSM: none (will have pacability to carry 4 x UGM-84 Harpoon aftrer Neptune II)
- Torpedoes: 14 x Atlas Elektronik SST-4, SUT Mod0 (8 x 533mm tubes) (unclear whether new torpedoes will be selected after Neptune II. If so, DM2A4 is the most favorite candidate. SUT Mod0's will be used until 2020's)
- Sonar: Atlas Elektronik CSU 3-4; Atlas Elektronik PRS 3-4 (will receive Atlas Elektronik Flank Array Sonar, but most probably not Circular Array Sonar like CSU-90)
- ESM: Thales DR-2000U
- C3: Thales WM8/42 SINBADS (will receive Atlas Elektronik ISUS-90-15, SATCOM, Link 11)
- Periscope: Carl Zeiss Optronik SERO 40 STAB (the same as Glavkos class)
Now,
1
IMHO Greek Navy's submarines' main areas of operation are Northern Aegean
(to prevent Turkish Navy exiting the Marmara and damage Turkish sea trade flowing through the Straits) and most importantly, Southern Aegean
(Mainland Greece - Crete - Cyprus line; again to prevent Turkish Navy and sea trade plus protecting the connection with Southern Cyprus, thus encircling Turkish mainland)
Submarines are not escort ships, they are hunters by nature. So, in this context, Greek submarines will most probably try to hunt down Turkish frigates and cargo vessels. I think that frigates will be on the top of the target lists, since Turkey is in no need of maintaining a "route" unlike the one existing between Greece and Cyprus.
I think Greek submarines' other priority will be hunting Turkish submarines, since they will most probably exert enormous pressure and try to cut on Greece - Crete - Cyprus connection. It is of crucial importance for Greece to maintain this line, thus any threat must be eliminated at all costs.
At all costs.
It seems Greek Navy decided that AIP PEM Fuel Cell is the cost they need to pay in order to protect the above mentioned line
(which reminds me of the well-known GIUK gap) and to encircle Turkey.
2
Turkish Type 209 / 1400Mod Gur class submarines have the same diesel engine
(MTU 396 series), same sonar
(Atlas Elektronik CSU-90), same C3 system
(Atlas Elektronik ISUS-90, Link 11, SATCOM), same weapon systems
(UGM-84, DM2A4) with Type 214 Papanikolis class. Main differences are AIP fuel cell, ESM and periscope sets.
The maximum depth of Papanikolis class is given as 400-450m. But it is not clear if this is operating, test or crushing depth.
(For example Italy's Longobardo class with 1,860t submerged displacement have 600m crushing depth)
In theory, Gur and Papanikolis have almost equal noise levels when running on either diesels or batteries, since both use the same machinery. Running on fuel cells will make not much difference than running on batteries, since both are electro-chemical processes.
So the main difference between Papanikolis and Gur classes is the duration of operation while submerged. Is this
that crucial for Aegean theater of operations, since Greece has practically hundreds of islands and islets to use for cover and base?
3
Having 4 AIP powered boats with long endurance may mean extending the reach of Greek submarine force to Cyprus, i.e patrolling around the island to prevent Turkish intervention in times of conflict and putting pressure on Turkish sea trade, especially from Iskenderun. The latter would mean suicide for Greece, since that trade line directly links Azeri oil to the world.
But on the other hand, longer patrols around Cyprus would indeed threaten Turkey much... If only Greece has enough submarines to:
1. Prevent Turkish fleet stationed in Golcuk from exiting Marmara
2. Protect Greece-Crete-Cyprus line
3. Prevent Turkish fleet from cutting the line
4. Prevent Turkish Navy from intervening Cyprus, supporting troops in Northern Cyprus
5. Harming Turkish sea trade in Mediterranean
4
Poseidon class have ~1,200t displacement. After Neptune II, displacement will slightly increase, maybe up to 1,300t.
Here are some AIP submarines with surfaced/submerged displacements:
Type 212 (Germany): 1,450 / 1,830
Type 214 (Germany): 1,700 / 1,850
Gotland (Sweden): 1,240 / 1,490
Asashio (Japan, experimental): 2,900 / 3,250
Agosta 90B (France): 1,570 / 1,760
Turkey's projected 6 AIP submarines will have 1,800t - 1,900t displacement.
Portugal ordered 2 Type 209 / 1400+ boats with AIP system. Displacement will be more than 1,400t.
When entered service, Poseidon class will be the smallest submarine with AIP.
Is it worth putting expensive AIP system into a 1,200t boat? Especially a PEM system which requires a lot of precious space for fuell cells and catalysers?
Is it worth making so much hard work on a 25+ years hull, i.e cutting the hull, inserting a freshly built module and "gluing" the hull back again?
Well, except the AIP part, Neptune II is a sound project. But, after all, is it really cost-effective to put so much effort and make so many modifications to an already old hull which already has limited space?
I don't think so.
5
Type 214 is indeed a very modern, powerful submarine. AIP, without doubt enhances its opeational capability by providing much longer patrolling time while submerged. But then again, it is the torpedoes that sink the ship. In addition, AIP is not a must for a submarine, "silence" is a must, good sonars is a must.
AIP is a force multiplier, only when the operational requirements dictate it. If not, it's a waste of valuable sources to put so much (~1.5 times or more than a conventional diesel electric boat) money for a boat which in turn will probably not give proportional effectivity. In other words, if the balance between operational requirements and resources is not well set, AIP diesel electric submarine will definitely not be a cost-effective investment.
6
Even though submarine launched version SCALP Naval is fired from 533mm tubes, I would not count much on seeing it being fired from a diesel electric submarine, especially if that submarine is using German made combat control systems. Even so, it would not be a wise tactical move to spare a submarine or two for striking land targets with cruise missiles and creating a huge gap in the limited submarine fleet that will try to seek and destroy Turkish submarines and frigates, in a crowded sea, swarming with a wide array of ASW assests including Barbaros class FFG's, 11 x MilGem class corvettes, 24 x S-70B-28's, 6 x CN-235MPA's, 10 x ATR-72MPA, naval MALE UAV's.
Just my two kurus'...
