Oliver Hazard Perry class Frigate reactivation proposal (2017)

[Grey Havoc]

https://blog.usni.org/posts/2017/06/28/if-we-bring-the-ohp-back-lets-do-it-right
http://www.military.com/daily-news/2017/06/13/navy-taking-hard-look-pulling-frigates-out-mothballs.html

Hmmm.

 

[Sherman Tank]

Hope they kept some spare rudders around.

 

[Forest Green]

Project GENESIS: How Turkey Resurrected Its Secondhand Oliver Hazard Perry Class Frigates

Project GENESIS not only breathed new life into the aging Oliver Hazard Perry class frigates, but it also set the country up to build its own advanced warships.

www.twz.com

 

[Tzoli]

Fascinating! It is like the modernization of the WW1 warships before WW2! And show if enough willpower is avaliable, older vessels could be modernized as well! It's a shame the USN sold and scrapped them rather modernizing them like the Turkish did.

 

[TomS]

Fascinating! It is like the modernization of the WW1 warships before WW2! And show if enough willpower is avaliable, older vessels could be modernized as well! It's a shame the USN sold and scrapped them rather modernizing them like the Turkish did.

Fundamentally the same as the RAN FFGup upgrades. But not something the USN could really have used.

The USN retired the FFGs (after briefly using them sans missiles) because of the manpower costs more than anything else. And yes, obviously the DDG-51s that replaced them also required large crews but there were industrial policy (and political) reasons that the Navy needed to keep building new DDGs rather than keeping old FFGs running.

 

[A Tentative Fleet Plan]

I have to admit I'm really sceptical about modernising ships by adding an entirely new combat system and sensors, it seems that you're paying a significant proportion of the cost of a new ship (which could last 20-40 years) to extend the life of an older vessel by a decade. Especially when the ships involved are still limited to a single fire channel.

Interwar modernisations made some sense, when treaty limits prevented the construction of new ships, and they were before an era when "steel is cheap, and air is free" was as true as it is now, combat systems were not a driver of cost to anywhere near as much as they are now.

 

[JoeCalPo]

Another issue is their vulnerability, having only the single screw. They might be useful to smaller countries, as a gun and helicopter platform, but there are cheaper alternatives for such that would provide a modern vessel.

 

[apparition13]

Four were upgraded with an 8 cell Mk-41 with 32 ESSM and Smart-S (mk-2 in this case) radars. The information I can see on the radars says they can track 500 (or 700, depending on the source) surface and air targets, but not how many separate targets it can attack at once. Does anyone know?

 

[1Big Rich]

I have to admit I'm really sceptical about modernising ships by adding an entirely new combat system and sensors, it seems that you're paying a significant proportion of the cost of a new ship (which could last 20-40 years) to extend the life of an older vessel by a decade. Especially when the ships involved are still limited to a single fire channel.

The late Stuart Slade once said words to the effect that electronics have whittled down the world's reserve fleets. By the time the electronics of a given platform are updated, for the expense one might as well construct a new ship.

Regards,

 

[snne]

It was a cheap modernization at the time that enabled the ships to remain relevant for another 15 to 20 years.

Four were upgraded with an 8 cell Mk-41 with 32 ESSM and Smart-S (mk-2 in this case) radars. The information I can see on the radars says they can track 500 (or 700, depending on the source) surface and air targets

 

[A Tentative Fleet Plan]

It was a cheap modernization at the time that enabled the ships to remain relevant for another 15 to 20 years.

They're limited to a single STIR illuminator, the ships were barely relevant when they were laid down, let alone now.

The modernisation almost certainly wasn't cheap, given it consisted of the most expensive component of a warship.

 

[TomS]

They're limited to a single STIR illuminator, the ships were barely relevant when they were laid down, let alone now.

And a CW channel in the CAS ball as well. But still marginal at best.

 

[that_person]

Fascinating! It is like the modernization of the WW1 warships before WW2! And show if enough willpower is avaliable, older vessels could be modernized as well! It's a shame the USN sold and scrapped them rather modernizing them like the Turkish did.

Yeah, good luck trying to do a meaningful refit to the Perrys.

http://archive.gao.gov/f0302/108301.pdf

 

[sferrin]

Fascinating! It is like the modernization of the WW1 warships before WW2! And show if enough willpower is avaliable, older vessels could be modernized as well! It's a shame the USN sold and scrapped them rather modernizing them like the Turkish did.

Could be worse. They SANK the Spruances, even those with the Mk41 VLS.

 

[Tzoli]

Yeah, good luck trying to do a meaningful refit to the Perrys.

http://archive.gao.gov/f0302/108301.pdf

Erm.. the Turks actually did that as the start of the thread shows. Or you know another Oliver Hazard Perry class?

 

[that_person]

Erm.. the Turks actually did that as the start of the thread shows. Or you know another Oliver Hazard Perry class?

GENESIS doesn't really do much. It adds a new combat system, a new VSR, and a Mk41.

First, the combat system updates are great, I'll give them that. But new computers alone doesn't actually do much, you need the hardware to support it. This is were the limitations of the Perry hull really come into play.

They changed the VSR which is great, but kept the 2 pieces that were in most need of replacement, the STIR and Mk13.

Instead of replacing the latter, they bolted on an 8-cell self-defense Mk41. This achieves nothing. You can now launch 32 ESSMs. Great. The ship isn't gaining anything meaningful, it doesn't take on a new mission set, it doesn't help the carrier group, it doesn't actually do anything.
Self-Defense Length cells are so limited in length they don't expand the payload set, which nullifies the point of using a VLS.

Regarding the STIR, it makes the ESSM addition borderline worthless.
Only 1 director means it can only illuminate targets in 1 direction, leaving anything outside of that narrow arc un-illuminated. And even the modernized STIRs only have 2 illumination channels, so good luck having more than 3-4 ESSMs airborne at any given time.
Had the replaced the STIR and CAS with a new system, say something analogous to SPY-5, they would be in a much better position.

Oh, and one more thing. Perrys were only designed to last 25 years. The last Perry commissioned in 1989(?), so all the hulls would've reached their designed service life in 2014. That was a full decade ago. The ships are held together with duct tape and bubblegum.

 

[Dilandu]

I have to admit I'm really sceptical about modernising ships by adding an entirely new combat system and sensors, it seems that you're paying a significant proportion of the cost of a new ship (which could last 20-40 years) to extend the life of an older vessel by a decade. Especially when the ships involved are still limited to a single fire channel.

Well, merely installing VLS in place of Mk-13 would allow Perry's to use ESSM and ASROC - which would significantly increase their capabilities even if not much else would be changed.

 

[Yellow Palace]

Could be worse. They SANK the Spruances, even those with the Mk41 VLS.

They could have run on for up to another decade, budgets permitting, but the scope for further upgrades was limited and the handful that ran out their full service life were pretty tired by the end. Using them for SINKEX means getting useful trials data, and you don't have to spend time telling people why they can't be refitted.

Oh, and one more thing. Perrys were only designed to last 25 years. The last Perry commissioned in 1989(?), so all the hulls would've reached their designed service life in 2014. That was a full decade ago. The ships are held together with duct tape and bubblegum.

Extending the life of a ship from 25 years to 30 years reportedly costs as much in life extension refits and increased operating costs as building a replacement. The combat systems are outdated, the condition of the ship is poor, and the crew is larger than for a modern ship.

That's one of the reasons why the Royal Navy has shrunk so badly. A lot of money has been spent on extending Type 23s - designed for a 18 year service life, with no combat system replacement - to last in excess of 30 years. The 2087/Merlin system should have been going into new hulls twenty years ago, after the Type 42 replacements entered service ten years before that....

 

[A Tentative Fleet Plan]

Well, merely installing VLS in place of Mk-13 would allow Perry's to use ESSM and ASROC - which would significantly increase their capabilities even if not much else would be changed.

On the modernised OHPs, the Mk 41 VLS was deployed forward of the Mk 13 though, and I'm not sure if it was strike length, tactical length or self-defence length.

As for ESSM, if they're Block 1s they only increase magazine depth, still being dependent on the two fire channels of the STIR and Mk 87 FCS for illumination. Block 2s with Terminal Active Homing would massively increase capability, with number of potential engaments only being limited to the number of missiles in the VLS.

 

[TomS]

Not even close. The Mk13 was deployed in the 60s. (Charles F. Adams class) The Mk 41 wasn't even on paper until the late 70s.

Not chronologically, physically. The Mk 41 is installed FORWARD of the Mk 13, rather than replacing as Dilandu said.

It is interesting that no one ever pulled the Mk 13 and dropped Mk 41 in its place. Both the Turks and Australians felt it was better/easier to add a new module forward of the Mk 13 instead. Because at best, you get four Mk 41 modules (32 cells) in that space, and even that may require moving a fair bit of structure around the corners of the new opening (roughly 7m x 5m, compared to a roughly 5m circle for the Mk 13). A low impact mod fits only 16 cells.

And it costs you Harpoon; at the time there were zero options for an antiship missile that fit in a Mk 41.

 

[Hood]

I'm not sure if it was strike length, tactical length of self-defence length.

The Mk 41 Mod 5 was tactical length, something that seems to be borne out by this model of the Australian refit.

 

[acelanceloet]

Fitting VLS instead of the Mk 13 is literally fitting a square peg into a round hole.

Something interesting to note is that the Mk 13 has quite a big hole in the ships deck compared to the ships beam. This hole then goes all the way to the ships waterline. The section in front of the pilothouse is a relatively high-stress area, so big holes in a deck there are normally avoided if possible. If you do put a hole in, you round the edges and strengthen the area around it.

Putting a VLS on a perry hull in (roughly) that location is proven possible by the proposals for the last Perry for Taiwan, which in the end was build to the standard design but fitting a big bank of VLS in an quite modified design was considered.

However! Refitting an perry with VLS would mean not just the VLS taking more space, but also those reinforcements would have to be redone. The area modified/rebuild would thus be almost everything between where those additional VLS were added and the superstructure.

In comparison, adding a tactical length VLS forwards above the sonar rooms is in an area with less stress (the closer to the ships midship the higher the stresses, normally, and further away from big changes in weight and cross section) only influences those sections the VLS is placed into, as the hole is smaller and the reinforcements just need to keep the strength of the decks the holes were made in the same and support the weight of the VLS.

So, what would you do. Remove the Mk 13 to fit 16 or 32 cells instead of the space for 40 missiles in the Mk 13, or just choose the much cheaper, simpler, more reliable option and keep the Mk 13 and add some VLS in which you can quadpack ESSM, and just keep the standards in the Mk 13.

 

[Brickmuppet]

Fitting VLS instead of the Mk 13 is literally fitting a square peg into a round hole.

Something interesting to note is that the Mk 13 has quite a big hole in the ships deck compared to the ships beam. This hole then goes all the way to the ships waterline. The section in front of the pilothouse is a relatively high-stress area, so big holes in a deck there are normally avoided if possible. If you do put a hole in, you round the edges and strengthen the area around it.

Putting a VLS on a perry hull in (roughly) that location is proven possible by the proposals for the last Perry for Taiwan, which in the end was build to the standard design but fitting a big bank of VLS in an quite modified design was considered.

However! Refitting an perry with VLS would mean not just the VLS taking more space, but also those reinforcements would have to be redone. The area modified/rebuild would thus be almost everything between where those additional VLS were added and the superstructure.

In comparison, adding a tactical length VLS forwards above the sonar rooms is in an area with less stress (the closer to the ships midship the higher the stresses, normally, and further away from big changes in weight and cross section) only influences those sections the VLS is placed into, as the hole is smaller and the reinforcements just need to keep the strength of the decks the holes were made in the same and support the weight of the VLS.

So, what would you do. Remove the Mk 13 to fit 16 or 32 cells instead of the space for 40 missiles in the Mk 13, or just choose the much cheaper, simpler, more reliable option and keep the Mk 13 and add some VLS in which you can quadpack ESSM, and just keep the standards in the Mk 13.

...or shoot Harpoons. 40 Harpoons is an interesting capability. Possibly not a practical one, but interesting.

 

[Yellow Palace]

...or shoot Harpoons. 40 Harpoons is an interesting capability. Possibly not a practical one, but interesting.

If you wanted to shoot 40 Harpoons at something, you'd want simultaneous arrival to saturate defences. A Mark 13 would be poorly suited to achieving that.

I always thought it was a bit odd that a Mark 13 derivative that could handle ASROC wasn't developed. Would have been a useful addition to the FFGs.

 

[TomS]

I always thought it was a bit odd that a Mark 13 derivative that could handle ASROC wasn't developed.

I'm not sure ASROC would fit in the Mk13 magazine without redesigning the missile (at very least for folding fins).

 

[TomS]

BTW, I found another good diagram showing jsut how little room there is along the sides of the Mk 13 in the FFG, especially near the bottom. Putting a block of four MK 41 modules in there might not even leave room for a companionway to get to the forward spaces.

 

[acelanceloet]

If you wanted to shoot 40 Harpoons at something, you'd want simultaneous arrival to saturate defences. A Mark 13 would be poorly suited to achieving that.

I always thought it was a bit odd that a Mark 13 derivative that could handle ASROC wasn't developed. Would have been a useful addition to the FFGs.

An Mk 13 that could fire Mk 26 would very quickly become over Mk 26 in size. Which meant that the answer to an Mk 13 that fired ASROC would be more or less the Mod 0 Mk 26, which was equal in size but with an square footprint instead of round (but could take less missiles then the extremely compact Mk 13)

Mk 13 could be so compact partially because all it's missiles were the same size.

 

[that_person]

BTW, I found another good diagram showing jsut how little room there is along the sides of the Mk 13 in the FFG, especially near the bottom

I’ll do you one better, take a look at the general plans.

 

[Yellow Palace]

I'm not sure ASROC would fit in the Mk13 magazine without redesigning the missile (at very least for folding fins).

If it won't fit in the same space as Standard MR, then the whole thing is unviable. On paper it's a smaller missile (2 inches longer than SM-1, but still shorter than SM-2), including fin span, though the devil is in the detail on these things.

 

[TomS]

If it won't fit in the same space as Standard MR, then the whole thing is unviable. On paper it's a smaller missile (2 inches longer than SM-1, but still shorter than SM-2), including fin span, though the devil is in the detail on these things.

SM-1MR has folding fins. ASROC does not seem to. Fin-span is 16.5 inches, which is seems Mk 26 could handle, but Mk 13 could not.

Still, if they had wanted to put AASROC in the MK 13, folding fins would have been an easy modification. The bigger problem might have been that Mk 13 needed a fair bit of modification to handle nuclear weapons (hence the Mk 14 proposed for Typhon) including some way to access the missiles and unlock them from the rail (each rail had a key lock to positively retain a nuke until released). And the torpedo version of ASROC was not regarded as all that useful; the nuke was the decisive weapon.

 

[Airbus A340]

The thread mentioned Stuart Slade and also the disposal of the Spruances.

Slade, on his now defunct board, posted that an air defense system costs around 300-400 million dollars. When you look at a Spruance size ship you can spend another 300-400 million, which will be somewhere between 15-40% of the cost of building a ship that size, in order to add Aegis. Without Aegis you spend all that money on the ship, the crew, the fuel, the maintenance but do not have Aegis. It's just not cost effective.

Slade explained why the Spruances were disposed of. He claimed that the gearing was built for 80,000 shp and that the LM2500 engine was upgraded from 20,000 to 25,000 shp while the Spruance was being designed. He claimed that the gearing was not upgraded and that handling 100,000hp with an 80,000hp gearing set had left the Spruances worn out.

The operating cost of a Spruance per year is about the same as a Burke but the Spruance lacked Aegis. Maybe not a huge deal a decade ago but now, with hypersonics and antiship ballistic missiles, the ships are vulnerable. I saw somewhere that the Spruances used linoleum in order to make the ships more habitable. The linoleum hid corrosion and some of the early Spruances suffered greatly for this.

The consensus on Slade's old board was that upgrading ships is a political issue, not a rational decision. It's easier for politicians to ask for money to upgrade old ships than it is to buy new ones. DK Brown said that the cost of the Type 23 hull was about 8% of the cost of the ship. Slade pointed out that running costs rise sharply as the ship reaches and exceeds the designed life of the ship. It's just not worth it to upgrade ships with new hardware. Politicians make it happen but any systems engineer can calculate how it is better to build ships with a designed lifespan and then retire them. Upgrades are software, adding new weapons or other features lime common or ECM antennae. Ripping out important parts of the ship and putting new stuff in makes no sense.

It's sad to see Slade's old board gone. There was a lot to learn there about military technology.

 

[acelanceloet]

I would love to see sources on that upgrade to 25k shp, yes the LM2500's design was capable of that but I have IIRC not seen any reference to the LM2500's on the Spruance being (much) more then 20000 shp. Such as change would likely also change propeller design, and the Spruance was as build already more powerful then needed for it's requirements (the original design had just 3 LM2500 in a more complex electrically coupled propulsion train) and IIRC the Perry's and the Tico's used the same gearboxes and LM2500 as used on the Spruance? So shouldn't that problem be a lot more widespread?

It is perfectly possible to downrate turbines (might even make them more efficient in some cases) so even if the LM2500's were improved during the design process of the Spruance they could have been limited somewhat instead of running the propulsion train out of spec (this was for example done on the Dutch Tromp class, where the industry was unable to provide variable pitch propellers to handle the full power of the Olympus gas turbine at that point)

 

[Airbus A340]

I would love to see sources on that upgrade to 25k shp, yes the LM2500's design was capable of that but I have IIRC not seen any reference to the LM2500's on the Spruance being (much) more then 20000 shp. Such as change would likely also change propeller design, and the Spruance was as build already more powerful then needed for it's requirements (the original design had just 3 LM2500 in a more complex electrically coupled propulsion train) and IIRC the Perry's and the Tico's used the same gearboxes and LM2500 as used on the Spruance? So shouldn't that problem be a lot more widespread?

It is perfectly possible to downrate turbines (might even make them more efficient in some cases) so even if the LM2500's were improved during the design process of the Spruance they could have been limited somewhat instead of running the propulsion train out of spec (this was for example done on the Dutch Tromp class, where the industry was unable to provide variable pitch propellers to handle the full power of the Olympus gas turbine at that point)

The explanation sounded reasonable but I've never seen it elsewhere. That's also where I read that SM-1 on the OHP was not very capable. It's always interesting to see posts by someone who works in the industry. Sometimes they speak pretty cautiously. Slade's board was one of the only places you saw people from the industry talking with such assurance so maybe that's a red flag. There was lots of interesting stuff there and also stuff that was questionable. For example, speed/altitude being a better way to go than stealth.

I do know that Spruance captains did crash backs and sometimes raced Bainbridge or Truxtun. I've also read that Spruances were handled pretty roughly, as in the throttles were raced full forward from a low setting, etc.

 

[isayyo2]

That's also where I read that SM-1 on the OHP was not very capable

Being saddled with a 2D SPS-49 rather than a 3D SPS-52/48 radar seems to be the biggest “red flag” for SM-1 issues….

 

[sdmuleman]

The thread mentioned Stuart Slade and also the disposal of the Spruances.

Slade explained why the Spruances were disposed of. He claimed that the gearing was built for 80,000 shp and that the LM2500 engine was upgraded from 20,000 to 25,000 shp while the Spruance was being designed. He claimed that the gearing was not upgraded and that handling 100,000hp with an 80,000hp gearing set had left the Spruances worn out.

I would love to see sources on that upgrade to 25k shp, yes the LM2500's design was capable of that but I have IIRC not seen any reference to the LM2500's on the Spruance being (much) more then 20000 shp. Such as change would likely also change propeller design, and the Spruance was as build already more powerful then needed for it's requirements (the original design had just 3 LM2500 in a more complex electrically coupled propulsion train) and IIRC the Perry's and the Tico's used the same gearboxes and LM2500 as used on the Spruance? So shouldn't that problem be a lot more widespread?

This doesn't make a lot of sense to me either. Never served on a 963, but I was on a CG and spent some time in the engineer dept.

There is some truth in the statement, as the LM2500 is capable of 25k SHP and the engines are essentially the same between CG and DDG. However, in the CG (and presumably 963 class) the engines are controlled to limit shaft torque, so unless things went badly wrong in the control system, it should protect itself from damage.

It is possible that the system I worked on was added later to mitigate problems found in the 963 class, but I haven't seen anything to indicate this, nor any indication that these ships were ever run above 80k SHP.

Now, it is true that the 963 and FFG-7's were the first widespread use of the high power GT plant and CRP system, and there's some particular ways this differs from a steam reduction gear, so it's entirely possible there were design defects in the original ones. I do know some of the FFG's had MRG problems, though I'm not familiar with the details.

In general though I am fairly confident that the ships were retired more for capability reasons than being worn out. The fleet was shirking, money was tight and fundamentally the 963's really weren't good for much that a DDG couldn't do just as well with the added benefit of having better AAW capability. From a strictly technical perspective many things could have been done to keep them useful, but there wasn't any money, nor a requirement for them.

 

[sdmuleman]

Being saddled with a 2D SPS-49 rather than a 3D SPS-52/48 radar seems to be the biggest “red flag” for SM-1 issues….

MK92 had an adequate 3D capability for the range of the missile. Long range 3D (i.e. Mk48) is only needed if you're trying to do long range missile engagements or control aircraft, neither of which FFG-7 is designed to do. Remember that FFG-7 is a local AAW platform, not area air defense. The SM-1/Mk-92 system worked fairly well for what it was designed to do. Biggest problem in the modern era is outdated electronics.

 

[sdmuleman]

I do know that Spruance captains did crash backs and sometimes raced Bainbridge or Truxtun. I've also read that Spruances were handled pretty roughly, as in the throttles were raced full forward from a low setting, etc.

All the gas turbine ships can do this, and do so fairly routinely. It's completely within the design capability of the plant and really isn't especially hard on them. The biggest danger to the plant is excessive torque, which in an GT plant is controlled automatically. On a steam plant it's more dangerous as careless operation of the throttle could exceed toque limits, and there's interaction between the turbine and boiler operation that can cause problems.

 

[TomS]

I do know that Spruance captains did crash backs and sometimes raced Bainbridge or Truxtun. I've also read that Spruances were handled pretty roughly, as in the throttles were raced full forward from a low setting, etc.

Remember that the USN's GT ships rely on controllable, reversible-pitch props, so crash-backs, for example, do not require reversing the shaft or gearbox rotation at all. The prop blades reverse pitch while still turning the same direction, so the stress from things like crash-backs will be in the prop hubs and to a lesser degree on the thrust bearings, but the gear box keeps spinning the same direction and should not be terribly stressed by such antics.