PNS Azmat Class - Fast Attack Missile Craft | Updates & Discussions.

[S.Y.A]

Yes! speed is medium to low....it needz to be near 50 Knots instead of 30knots for fast attack crafts....30 knots is normal speed......

at least 40-45

 

[Penguin]

at least 40-45

It's a patrol boat, with missiles. For effective patrolling, you need endurance. To get endurance (incl. range) , you have to have economical propulsion. So, you you put in fewer or different engines than if speed were of the essence, with less SHP and you sacrifice speed. That's incidentally also why this is a 500 ton boat and not a 220 ton Type 022: if you stay out longer at sea, you need a bigger crew and creature comforts (galley, beds etc)

 

[Armstrong]

It's a patrol boat, with missiles. For effective patrolling, you need endurance. To get endurance (incl. range) , you have to have economical propulsion. So, you you put in fewer or different engines than if speed were of the essence, with less SHP and you sacrifice speed. That's incidentally also why this is a 500 ton boat and not a 220 ton Type 022: if you stay out longer at sea, you need a bigger crew and creature comforts (galley, beds etc)

Penguin, a noob question, if you will : Do engines come in different configurations (settings) ? Which is to say just as a Jeep may switch from a 4x4 to a front (or rear)-wheel drive; can ships switch from a full power setting to give chase or to escape (hence the 40-45 that he was talking about) to a setting that economizes on fuel and hence allows you to stay out longer ? I'm not sure if I can elucidate well enough because I know next to nothing about ships....but to use another example - an Air craft's after-burner switched on for pursuit or escape to a normal thrust for cruising !

 

[Capt.Popeye]

Penguin, a noob question, if you will : Do engines come in different configurations (settings) ? Which is to say just as a Jeep may switch from a 4x4 to a front (or rear)-wheel drive; can ships switch from a full power setting to give chase or to escape (hence the 40-45 that he was talking about) to a setting that economizes on fuel and hence allows you to stay out longer ? I'm not sure if I can elucidate well enough because I know next to nothing about ships....but to use another example - an Air craft's after-burner switched on for pursuit or escape to a normal thrust for cruising !

Hi,
There is an answer to that. Multiple engines is one of them and usually the best option. A single engine of any type (Steam, Diesel or Gas Turbine) can also have its speed regulated, some what like a car you can control the fuel flow and hence the RPM/speed.

However this method is not suitable for Gas Turbines (which are getting increasingly popular now for various reasons) since their efficiency (and fuel economy) is achieved only at certain band of RPM/speed. That said, Gas Turbines are the fastest revving (responsive) means of Marine propulsion.

Diesel Engines are still in vogue because they are easier to run and maintain as well as they give the best fuel economy. Plus their RPM/speed can be regulated over a wide band. But the down-side is they are not so responsive and cannot build up speed very rapidly. Nor can they in direct drive achieve very high speeds without gearing.

Steam propulsion is going out of vogue, because the whole plant takes a great deal of time to start up (actually need a great deal of preparation to be put into operation). But they are moderately responsive and with suitable gearing can achieve reasonably high RPM/speed.

Usually to tackle the scenario that you have described, multiple engines are used each driving a different shaft/propellor. A common arrangement is a central shaft/propellor driven by a Diesel for economical cruising/endurance and two outboard shafts/propellors (one on either side) driven by Gas Turbines for rapid acceleration/burst speed. The Diesel/GT engines may work together (CODAG) or separately (CODOG).

Sometimes multiple Gas Turbines may be used to drive the shafts. Say 4 GTs to drive 2 shafts propellors through gear boxes. Deprending on the speeds required the GTs will be coupled or de-coupled to the gear boxes.

Hope that helps.

 

[Donatello]

Penguin, a noob question, if you will : Do engines come in different configurations (settings) ? Which is to say just as a Jeep may switch from a 4x4 to a front (or rear)-wheel drive; can ships switch from a full power setting to give chase or to escape (hence the 40-45 that he was talking about) to a setting that economizes on fuel and hence allows you to stay out longer ? I'm not sure if I can elucidate well enough because I know next to nothing about ships....but to use another example - an Air craft's after-burner switched on for pursuit or escape to a normal thrust for cruising !

Not a noob question at all,

Yes Ships have propulsion systems that can have one power source or multiple.

For example, just for cruising, a ship can use it's gas turbine only. But if more speed is required in rough weather, they can engage the clutch and use another power source with the gas turbine, like electric motor + gas turbine.

check this page out, it has very good description of some of the 'hybrid' systems for ship propulsion....and check the diagrams. Very informative.

Combined diesel and gas - Wikipedia, the free encyclopedia

go to links on the right side to see each possible case scenario.

hope it helps!

 

[Armstrong]

@ Donatello and Cap. Popeye : Thanks guys !

 

[Penguin]

I think in smaller ships (under, say, 1000 tons) you do not tend to find the 'combined' propulsion type much, whether is is solely multiple diesels or multiple gasturbines or a combination. Such an arrangement requires reduction gears etc, which add to weight and volume, which is scarce in small ships. That doesn't mean examples can't be found, merely that it is not typical. Alternatively, boats get a pair of cruise diesels or turbines on one pair of shafts and boost diesels or turbines at one or more additional shafts. Or you get entirely different plant on the same ship in its patrol and in its attack variants.

One example is the Russian Tarantull class (a.k.a. project 1241.1/RE/.8 and variants, a.k.a. Veer class in IN). This 550 ton missile boat has a 2 shaft COGAG plant with 2 turbines at 11000 hp each, plus 2 cruising engines at 4000 hp each (there are diesel and turbine versions of the cruising engines), which let these boats reach 42 knots. Range is 1650 at 14 knots (26 km/h),

One version of these ships was developed especially for coastal anti submarine warfare and patrol. This is known as the Pauk class corvette or Project 1241.2 (Abhay class in IN). It is is slightly longer and has diesel engines (2 shafts, M504 diesels, 20,000 shp). Speed is 28–34 knots1,650 nautical miles (3,056 km; 1,899 mi) at 14 kn (25.9 km/h; 16.1 mph). So, this does without the boost turbines, compared to Tarantul.

Compare also the propulsion arrangement of the PRC Hegu (Russian Komar) missile boat to that of the contemporary Type 62 Shanghai. The former (a missile fac) has as propulsion: 4 shaft M-50F diesels 4800 hp, for as speed of 44 knots and a range of 600 nm at 32 knots The latter (an asw patrol ship) has 2 × Soviet M50F-4 diesel engines, 1,200 hp (895 kW) plus 2 × 12D6 diesel engines, 910 hp (679 kW) for a top speed of 28.5 knots and a range of 750 nm (1,390 km) at 16.5 knots. Different task, different boat, differen propulsion solution.

 

[nomi007]

i think pn choose really good fac in limited funds

 

[Penguin]

i think pn choose really good fac in limited funds

It will be used all or mostly in peacetime, for which duties it is quite suitable. In wartime, it is a unit with capabilities matching its essentially defensive tasks, to be conducted under cover of landbased aviation. So, yeah, value for money.

 

[Armstrong]

It will be used all or mostly in peacetime, for which duties it is quite suitable. In wartime, it is a unit with capabilities matching its essentially defensive tasks, to be conducted under cover of landbased aviation. So, yeah, value for money.

Hey, Penguin ! Can this vessel be used adequately in anti-piracy operations if it were operating solo ?

 

[S.Y.A]

It will be used all or mostly in peacetime, for which duties it is quite suitable. In wartime, it is a unit with capabilities matching its essentially defensive tasks, to be conducted under cover of landbased aviation. So, yeah, value for money.

what is the use when it will be used mostly in peacetime? I still think it should be faster because the "hit and run" role everyone has been talking about would not be very useful if its slow and that too if an aircraft is on its tail

 

[Capt.Popeye]

Hey, Penguin ! Can this vessel be used adequately in anti-piracy operations if it were operating solo ?

Hi,

It certainly can be. I'd say that would be a very appropriate use of this craft. It has suitable armament to handle say (actaually the missiles are a bit of over-kill for the purpose) ; the Somali Pirates.
Apart from being suitable for coastal patrolling, monitoring illegal fishing or intercepting contraband carrying craft or even in a SAR (Search And Rescue) role.

 

[ice_man]

during war this boat will be very good asset in terms of harbor denial and channel denial to the theme enemy. DESTROYERS & FIRGATES are more of an offesnive weapon which for Pakistan has traditonally been its submarines.

so during war this boat will help keep the channel open from enemy but definetly can't take out frigates or destroyers of the enemy.

 

[Donatello]

Azmat class boats can be used for anti-piracy. I think PN is getting these so that bigger ships, like Frigates can be called back from anti-piracy duties. This way boats that are cheaper to make and run, would be ideal for Anti-Piracy litorral roles.

 

[Penguin]

Hey, Penguin ! Can this vessel be used adequately in anti-piracy operations if it were operating solo ?

I would think so, though only relatively close to home (compared to e.g. Perry class and other frigates) or ... from a foreign base (i.e. close to their shore)

what is the use when it will be used mostly in peacetime? I still think it should be faster because the "hit and run" role everyone has been talking about would not be very useful if its slow and that too if an aircraft is on its tail

Hopefully all and otherwise most of its servicelife will be spent patrolling, rather than having at it with the eastern neighbour. Relative to aircraft even 50-60kt is slow...

Why do you think the Dutch navy let go of frigates for -admittedly equal sized - OPV? Because operating frigates on anti-pirate patrol work is not so cost-effective. OPVs do a better job, for less money.

during war this boat will be very good asset in terms of harbor denial and channel denial to the theme enemy. DESTROYERS & FIRGATES are more of an offesnive weapon which for Pakistan has traditonally been its submarines.

so during war this boat will help keep the channel open from enemy but definetly can't take out frigates or destroyers of the enemy.

While I agree with the first part of your post, you are saying the 8x c802 on Azmat FAC are less effective than the 8x C802 on Zulfiquar F22P? Or, that the latter is toothless?