During the Cold War, the US Navy concluded that lightweight
torpedoes were largely ineffective against Soviet submarines, in terms of
achieving a kill. Even heavyweight
torpedoes were questionable and thought to require multiple hits to kill. Lightweight torpedoes were considered more of
an annoyance to Soviet subs than a lethal threat.
Lightweight torpedoes are a lethal threat only to small,
lighter built diesel subs.
Lightweight torpedoes are not a ship-sinking threat to
anything much bigger than a patrol boat and are not capable of sinking surface
ships, either merchant or naval.
That being the case, why is the Mk54 lightweight torpedo so
ubiquitous throughout the surface Navy?
Wouldn’t it make more sense for ships to mount heavyweight torpedoes?
Here’s a brief comparison of the Mk48 heavyweight and Mk54
lightweight torpedo characteristics.
Characteristics vary, of course, depending on the exact model but these
are representative. Note the lightweight
torpedo’s warhead weight and range deficiencies compared to the heavyweight
torpedo.
- Sinking merchant ships
- Sinking submarines
- Sinking surface ships
- Destroying maritime structures (oil platforms and such)
Is the small size of the lightweight torpedo to have ammunition commonality with the air dropped torpedoes carried by helicopters? As I understand it, the lightweight torpedo can be fired out of triple torpedo tubes and carried by ASW helos. The Kaman Seasprite was relatively small, as helicopters go - I can only imagine the difficulties it would have had in trying to carry a Mark 48.
ReplyDeleteDestroying maritime structures like oil platforms can create an environmental disaster. These oil platforms have no defenses. I see no sense destroying them. If the Navy wants to destroy oil platforms then the Navy first should build AAW and ASW warships and special vessels for clearing the sea from the oil products.
ReplyDeleteYou can't be serious? War is an exercise in environmental disaster! Do you have any idea how many gallons of oil were spilled in WWII? If environmental impact is your major concern then you're in the wrong war! This is simply not a concern.
DeleteYou might also want to review Operation Praying Mantis where we attacked various platforms.
It is very unfortunate that when any war ends, many say that they will never allow war again. In peacetime, nothing is done to prevent the outbreak of war or to make its conduct ineffective in any environment. When a war begins, the military suffers very heavy losses, civilians are mobilized into the army and industry to provide for the military. In wartime, military-industrial complexes are built and work there until the end of the war. They are built by civilians who became builders in the war. But as soon as the war ends, gradual demobilization occurs. Instead, army sappers and naval mine-clearing ships are rapidly decreasing in number, and demining of mined areas of land and sea has been going on for tens, if not hundreds of years. Worse still, the ruins are not restored as quickly. Ecological disasters are almost never eliminated at all. Two options. The first is to design ships in such a way as to prevent natural disasters and oil spills. The second is to have specialized ships that would clean the sea surface from oil. They should be legalized no worse than medical ships, so that no one could shell them and had no right to do so.
Delete"design ships in such a way as to prevent natural disasters and oil spills."
DeleteThis is patently absurd. Again, if environmental concerns are a major factor then you have to seriously question why you're in the war.
This has actually been tried and, generally, failed miserably. We've tried building Eco-friendly munitions and weapons and, invariably, they have worse performance than their original, unfriendly counterparts. Over the last few decades, we've banned highly effective corrosion control coatings for warships and are paying the price in rotting ships.
One of the major targets in any war, by any side, will be oil tankers (just as in WWII). Do you see some way to sink them without releasing oil? Absurd!
CNO, I'm generally in agreement with you that real war is a nasty business and is bad for everybody, including wildlife.
DeleteHowever, I do wonder if there is a line that might not be crossed. Firing a torpedo into an offshore oil well is different than sinking a tanker---the oil well won't stop gushing, but eventually a tanker is just out of oil. On the operational level, the tankers probably stop or at least thin out after you shoot one or two, but there isn't a reasonable way for an oil well to stop existing after you blow one up. Alternatively, spraying the deck with machine gun or cannon fire might not produce a gusher while still shutting down production, though of course a much lower likelihood.
Do you have any historical references at hand? Is there any possibility that blowing open oil wells might prove disadvantageous for both sides? Are there considerations for submarine operations in oil-polluted waters? This seems like new ground, given how much offshore drilling has sprung up since WWII, and I'm not sure there is a definitive answer.
"Do you have any historical references at hand? "
DeleteReview the Desert Storm conflict and the oil well fires. Review the myriad industrial oil platform accidents that have resulted in oil leakages.
You appear to be trying to make something out of nothing.
Commander of Naval Opinions I have one question. Look at the situation. It has been reported that Iran has mined the Strait of Hormuz lately. We know tha the US Navy retired its all Avenger class mine hunters. Also we know that the LCS are not able to search and destroy the mines. The question is how to search and destroy the naval mines? I see you know very well how to design AAW, ASW, anti surface warfare ships, aircraft carriers, carrier aircraft and so on. Sure you know what kind of warships I needed to deal with naval mines. How to project them, deploy and do the mission - search and destroy naval mines. You say that you did an ideal fleet structure for the Navy, but there are no mine hunter warships. There is no way to ignore this vital thing. Write an article and post it on your blog. It is very actually.
ReplyDeleteThere is evidence that Iran has mined the strait, only unconfirmed rumors that may have been planted by Iran as part of a propaganda effort. There have been no reports of any ship encountering any mine.
DeleteThat aside, I've discussed the concept of mine clearance at length throughout the blog. Search the archives and you'll find a great deal of information.
I left out minesweepers and the like from the fleet structure page simply for space considerations. I also left out oilers, cargo ships, replenishment ships, etc.
What tags or keywords are relevant to this theme? Please advise. I want to study this topic thoroughly.
Delete“All of this leads me to ask, why isn’t the Mk48 standard on surface ships?”
ReplyDeleteThe need is clear, but to state the obvious: because the USN, particularly the surface navy, clearly does not value the capability that having a fast, deep diving torpedo with the explosive capability to sink or heavily damage whatever it hits provides.
The Navy also does not value modern EW systems, heavy anti-ship missile, fast logistics ships, and a host of other weapons and systems needed to prosecute war. Some of this is due to budget reality (these wars of choice in Vietnam, Iraq, Afghanistan, Iran etc. have impact!), and some of it is due to ignorance bordering on criminal negligence. We bear the fruit of a lack of focus on mission/threat/method/end-state lasting for decades.
If I was a committee chairman in Congress, I would haul every living SECNAV and CNO into session going back to Vietnam, and ask why they requested funding for all these ships, which are supposedly designed around the weapons they carry, and within the operational constraints governing their employment?
GAB
For helo's that's why we have lightweight torpedoes and the soviets built hundreds of diesel electric subs.
ReplyDeleteAs for surface ships I guess it's because they are fire and forget? while the heavy torps are wire guided so no rapid manuvering after firing.
Plus the 3 shot launcher and 3 lightweight torps weigh just a little more than a single heavyweight torp so having multiple heavyweight torps in a launcher is a lot more weight which US ships already struggle with according to what you have wrote about it.
Lightweight torpedoes are a very niche weapon. Their target set is small, lightly built diesel subs and that's about it. As noted in the post, a heavyweight torpedo has many more uses and would, therefore, be much more useful.
DeleteAs far as weight, the added weight of a heavy torpedo over a light torpedo is insignificant if designed in from the start. The 3500 lbs of a Mk48 torpedo is nothing compared to the 10,000 tons displacement of, say, a Burke class destroyer.
A Mk48 is a fire and forget the same as a Mk54 when used at the same range. The Mk48 wire guidance is a useful option that expands the torpedo's effectiveness, not a limitation!
It would seem that the Mk 54 lightweight torpedo would be applicable for implementation with ASW helicopters or ASROC.
DeleteThe Mk 48 would be awfully heavy in those applications.
But how much of the weight of a Mk 48's 3,700 lbs is part of the 31+ mile range of the weapon?
Theoretically, the ASW helicopter, or the ASROC launcher, should be placing the torpedo fairly close to an identified enemy submarine.
Why not design a lighter torpedo that doesn't sacrifice warhead capability, but instead saves weight by reducing the maximum range of the torpedo once it is in the water and activated?
The SH-60s should be able to carry even a Mk 48, so a lower weight torpedo should be well within its lift capabilities.
And the ASROC needs to be revised to increase its range anyway, so why not build a new system that accommodates a heavier rocket that can carry a torpedo heavier than a Mk 54 but lighter than a Mk 48?
Lutefisk
That's some great thinking!
DeleteMH-60R isn't carrying a mk 48. The hard point used to connect the lightweight torpedo's is a 2000lb hard point, not that even that weight is relevant. https://www.aviatorsdatabase.com/wp-content/uploads/2013/07/MH-60R-Seahawk.pdf
DeleteYeah, the short range of the Mark 54 is something we can mitigate for by deploying from helicopter and ASROC. Recall that lightweight torps were also dropped by P-3s on ASW patrol. Sure, one hit might not be that devastatibg, but a P-3 could carry up to 8 ASW torpedoes, plenty for follow on attacks.
DeleteI wonder how large a warhead would be necessary to get a high probability of a kill on a nuclear sub?
DeleteIt's not like the Mk 48 is some massive torpedo, I would want to reduce the warhead as little as possible.
But how much could be done?
Would a 500 lb warhead be big enough?
I wonder if the navy has done any studies on what they need from an ASW torpedo's warhead?
Lutefisk
@ Anon: "Different solutions for different problems"
DeleteGreat points, moreover the propellant in many _heavy_ torpedoes is also quite explosive adding to the destruction. Further, the deeper a submarine is, the more effective a torpedo detonation is, and there will be multiple powerful shock waves.
GAB
"lightweight torps were also dropped by P-3s"
DeleteDid someone say we shouldn't have lightweight torpedoes on P-3/8s?
I'm just saying, a lot of the Mark 54's disadvantages with regard to speed, range and warhead size go down when you can drop one pretty much right on top of your target. These are sacrifices made in order to get a torpedo small enough and light enough that it can be carried by small helicopters (the Seasprite is noticeably weaker than today's Seahawk) and survive being air-dropped by rocket or P-3.
DeleteThe Mark 48 doesn't need those sacrifices, because it's already in the water. Its challenges are that it's going to be fired at a target from a further distance than the Mark 54, so it needs to be faster, it needs more range, it needs more endurance to run longer. At that point, the torpedo is big enough that a 750 lb warhead doesn't compromise its performance.
"disadvantages with regard to speed, range and warhead size go down when you can drop one pretty much right on top of your target."
DeleteWhat a silly statement. EVERY weapon's speed and range becomes irrelevant when it reaches the target. Warhead size doesn't switch from a disadvantage to an advantage just because it's at the target. A small torpedo is ALWAYS going to be less effective than a large torpedo.
A hand grenade is just as effective, maybe more so, than an anti-tank missile when it's dropped down inside a tank. Should we eliminate anti-tank missiles?
"because it's already in the water."
If launched from a submarine. Surface ships would launch from deck and the torpedo would drop into the sea.
You need to improve the quality of your comments.
The point I'm trying to make is you can drop a torp right on top of that submarine using ASROC, a helo, or a plane. The Mark 48 is being fired from the ship, from a further distance away.
DeleteYou're correct on the warhead - i'd conflated two points I was trying to make, which was that 1) the range and speed issue are less pronounced because the torpedo is being delivered right ontop of the target before it begins its sprint, and 2) the warhead weight is a compromise to get a lightweight air dropped torpedo.
As for the warhead issue, we can fix that by changing the warhead from high explosive to a nuclear warhead, which was the initial concept for ASROC and SUBROC. The W54 nuclear warhead weighs only 51lbs, half the weight of the Mark 54's HE warhead, with a yield of around 20 TONS of TNT. It's small enough for tactical use, and the risks of radiation contamination will be reduced because this is an underwater detonation, where the seawater will be diluting the radioactive fallout. I don't see this as being an escalatory move, because our adversaries already have nuclear tipped torpedoes, and have had them for decades.
"If launched from a submarine. Surface ships would launch from deck and the torpedo would drop into the sea."
I was actually envisioning purpose built torpedo tubes in the hull, below the waterline, but I suppose that might be a little too difficult to do, engineering and design wise.
"The point I'm trying to make"
DeleteJust out of curiosity, did someone suggest eliminating lightweight torpedoes from helos, aircraft, or ASROC? Perhaps you noticed the last sentence in the post: "All of this leads me to ask, why isn’t the Mk48 standard on surface ships?" It appears that you're trying to create an argument where none exists.
You were asking why heavyweight torps were not standard on surface ships. What we have here, it's a matter of fitting a round peg into a square hole. The deck launcher torpedo tubes are really a marginal, secondary emploment of an acceptable weapon that is being used outside the main way it's intended to be employed. LWTs from deck launchers can only be a last resort defensive weapon. The offensive use of lightweight ASW torpedoes is via ASROC and aircraft. (The Navy, whenever it feels like doing ASW, wanting to do standoff ASW at a distance instead of playing tag up close with submarines.)
DeleteWhy did the Navy accept this? Because the Navy has deprioritised ASW and focused on AAW. Because for a time the Navy's paradigm was that it wasn't necessary to kill the sub, just chase it off is fine. Because to the Navy, this is a good enough option.
2 x Royal Navy mk viii torpedoes sank the General Belgrano in in 1982. This was an old style cruiser ex USS phoenix 1939 so armour etc I belive they have about 800 lbs warhead, so I would have thought 3 or 4 hits by a mk 54 should do some serious damage.
ReplyDeleteThe Belgrano was a forty year old, poorly maintained ship with a poorly trained crew sailing with all watertight doors open, according to reports. It was lucky to put to sea and not spontaneously sink!
DeleteThe Mk 54 lightweight torpedo has a warhead weight of around 95 lbs. Compare that to a heavy torpedo with 750 lbs warhead (Mk VIII) or whatever. I don't know exactly what torpedoes the RN sub had available.
IMHO, the only reason Navies have lightweight torpedoes is because helicopters can carry only lightweight torpedoes, and they are supposed to be the tool that can box a submarine and kill it. Lightweight torpedoes on a ship don't make any sense, but nor do heavyweight torpedoes. In any case, ASW works only in exercises, a submarine launching missiles from more than 50NM cannot be pursued.
ReplyDeleteYou don't study naval warfare, do you? As noted in the post, heavyweight torpedoes would be very useful for sinking merchant shipping, as one example.
Delete"a submarine launching missiles from more than 50NM cannot be pursued."
I almost don't know where to begin. Submarines have no magical targeting capability from 50 miles away. In fact, their long range sensors are fairly limited: zero field of view and only vague acoustic indicators at that kind of range. No target, no launch.
Surface ships will have helos ranging out from the ship, searching for submarines and between the ship's sensors and the helo's they have a very real chance of detecting a submarine. If we would develop a VL-ASROC-ER, we'd have a useful combination of sensors and weapons.
This is not to say that ASW is easy. It's not! But to think a submarine has some kind of magical capability is ignorant.
You need to study naval warfare tactics and capabilities.
At about 3,700 pounds each, how many Mk 48 torpedoes do you think a Romeo helicopter could carry?
Deletezero as designed. an S model could sling load a few.
DeleteJust a note: the Permit, Sturgeon and Los Angeles class submarines had ESM antennas in their masts. These could give enough data for the subs to launch Harpoon missiles on a bearing only launch, leaving the missiles to aquire and engage targets independantly.
DeleteOMG I forgot the Conops chapter where a Ticonderoga or a Burke would strike a merchant with their M48
Delete"Just a note: the Permit, Sturgeon and Los Angeles class submarines had ESM antennas in their masts."
DeleteJust a note: in war, the enemy will be doing the same thing we will: EMCON. There won't be any signals to "ESM".
A certain degree of understanding of naval warfare is required to comment intelligently on this blog. You need to improve your understanding of basic naval warfare concepts.
One caveat with using torpedoes is their time to target. Assume a horizon-range engagement at 25 km. The Mark 48 will take 12 minutes to impact the target, not accounting for any evasive maneuvers. The Harpoon, hardly a fast missile by any measure, will impact the target in 2 minutes.
ReplyDeleteEVERY weapon has caveats. Do you have any useful point to make?
Delete"One caveat with using torpedoes is their time to target."
DeleteAll things being equal, the missile certainly arrives sooner.
But I think that an underlying assumption that you are making is that all parties have total and complete situational awareness, in which case the faster arriverer would be preferred.
But in an EMCON environment, possible in the dark, or fog, or obscured by islands, the torpedo could be an effective first strike weapon.
If the enemy surface combatant is not alert on their sonar, or doesn't have sonar at all, they will likely not be aware of an inbound torpedo until it is too late (if at all).
Even if they do discover it, they will be required to simultaneously need to deal with the homing torpedo while also doing the same with inbound missiles and/or naval artillery shells, while also trying to return fire.
Seems like a force multiplier to me.
And if the torpedo does strike home, just like in WW2 it will be a significant emotional event for that surface ship.
Lutefisk
Given how hard it is to achieve a hit on a target, EVERY naval commander in the world would greatly prefer that hit be from a massively larger torpedo than a pinprick smaller one!
DeleteI wonder how much the development of ASROC influenced and limited the design of the lightweight torps, being as how they had to fit into the form factor of the ASROC rocket. And while individually each torpedo is short ranged with a small warhead, the matchbox launcher has 8 ASROCs ready to go, extending the torps range by another 6 miles.
ReplyDeleteAs short ranged as VLA is, it shoots out to 12 miles, meaning our total engagement range with lightweight torps delivered by VLA is 17 miles. That's a threefold increase in range over the fantail torpedo tubes (which I really think are more for last ditch self defense than offense).
We don't begrudge CIWS its short engagement range of 2000 yards, because it isn't a horizon range interceptor missile - that's the job of ESSM.
What we really should be doing is looking into redesigning ASROC, developing a VL-ASROC Extended Range variant. SM-6 and SM-2 saw credible range increases from being mated with new rocket boosters, surely we can do the same for ASROC!
During the Cold War Russian submarines had double hulls; a 50mm steel pressure hull and a thinner external hull for additional protection.
ReplyDeleteBack then the 95lb warhead of a lightweight torpedo exploding against the external hull would likely have been ineffective, however the same weight of explosive detonating directly against the 25mm - 50mm hull of a Virginia class submarine or the equivalent Russian boat would probably sink it.
Obviously the 750lbs of explosives of a Mk. 48 would be far more effective against surface warships and other targets.
The IJN's Type 12 lightweight torpedo has a 110lb
Deleteshaped charge warhead in response to the Soviets
having a double hull.
Something that isn't apparent from the chart is the procurement cost of the weapons. The Mark 54 has an average procurement cost of around 1 million USD; the Mark 48 ADCAP CBASS has a procurement cost around 4 million USD per unit. To an extent, that may explain the ubiquity of light torps throughout the surface fleet.
ReplyDeleteAlso, by carrying lightweight torpedoes, a ship gets to consolidate its magazine space and share the torps between its helo and the Mark 32 triple tube self defense launchers. Plus there's the space factor to consider: Six Mark 54s take up the same space as one Mark 48, and they're a lot easier to manhandle with the ship's crew, vs the Mark 48 which is literally one and a half tons. By the time you've loaded 4 Mark 48s on a ship, you could have loaded 24 Mark 54s. When you consider that weapons miss, and that your probability of hit goes up the more shots you take, well.
You're making a business case which is utterly irrelevant and one of the problems the Navy has. They're stupidly trying to run a warfighting organization like a business. The ONLY thing that matters in war is effectiveness.
DeleteTo use your "logic", rifle bullets take up far less space and weight than even lightweight torpedoes so we should procure them instead of torpedoes. Why don't we? We don't because they're utterly useless against ships and submarines. They're INEFFECTIVE. Just as lightweight torpedoes are far less effective than heavyweight torpedoes.
You're "logic" is also inherently flawed. If it takes four or six or eight lightweight torpedoes to produce the same effect as one heavyweight torpedo, you haven't saved any space/weight/cost at all and may actually be penalizing yourself.
"Six Mark 54s take up the same space as one Mark 48"
You fail to understand how heavyweight torpedoes are used and stored. For starters, THEY AREN'T STORED. They're used so seldom that they are loaded into a launcher and that's the end of it. There are no magazines or reloads so magazine consolidation, weight, and space are not factors.
You need to study naval warfare and drastically improve the quality of your comments.
Even if stored externally in deck launchers, anon has a point that you can fit in 6 Mark 54s for every Mark 48 carried.
DeleteBut this really begs the point of what is the intended conops of the ship employing such torpedoes, and again comes back to the age old question of whether we're doing standoff ASW, or playing tag with submarines at close range. If it's the latter, then the range benefits are less relevant (and we should instead optimise for faster speed and a larger warhead at the expense of range).
I have no issues with the Mark 54 or lightweight torps generally. Absolutely correct that they may not provide a one shot kill. So what? A damaged sub is also a good result and in some cases may be a functional kill — and in any case it is sitting duck for a follow on fatal shot. A mk54 has no ASUW capability, sure, but surface vessels have other and better alternatives to sink vessels at torp range. Some you can’t just swap out 54s for 48s, I’ve no issues with these trade offs.
ReplyDelete