# ASW options for small ships and vessels



## Colin Parkinson (22 Sep 2014)

My mind was wandering yesterday and wondering if we had to what sort of ASW detection gear and weapons would fit onto small vessels like a an Orca or Kingston class vessel, mainly as harbour approaches defence vessels? Anything like that been/being trialed?


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## Oldgateboatdriver (23 Sep 2014)

Best bet is to deploy a series of expandable sonobuoy, like the ones on MH's and LRMP's, and monitor from a small console on the bridge. We already use one or two such buoys deployed from Rhibs and a monitoring console ashore for anti-combat-divers harbour defence. If you want to be cute, fitting the Orca's with a helicopter dipping sonar over the stern would be an easy mod. For the MCDV's, they are big enough to get a full tail on their stern.

The real problem is ASW weapons on such small crafts: Nowadays our primary weapon is the Mk46 torp and that plus the launch tube would be pretty heavy and cause stability problems.

Question is, really, why would we want to do that? For harbour approaches, much better to deploy fixed bottom ASW sonar nets monitored from shore and then use a helicopter for prosecution.


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## Stoker (23 Sep 2014)

For the KINGSTON class a small towed array could be used, the class have already had a towed array fitted in the past. This gear could be routed into a control ISO container and used as a mission fit. A port and stbd torperdo launcher could be fitted on the sweepdeck and the stability wouldn't be effected aversely. The ship would need a HP air upgrade as the HP system onboard doesn't put out sufficient pressure.


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## SeaKingTacco (23 Sep 2014)

Why would you want to get a ship (any ship) within torpedo range of a submarine?

The whole of point ASW is get the sub, without that happening.


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## Colin Parkinson (23 Sep 2014)

Oldgateboatdriver said:
			
		

> Best bet is to deploy a series of expandable sonobuoy, like the ones on MH's and LRMP's, and monitor from a small console on the bridge. We already use one or two such buoys deployed from Rhibs and a monitoring console ashore for anti-combat-divers harbour defence. If you want to be cute, fitting the Orca's with a helicopter dipping sonar over the stern would be an easy mod. For the MCDV's, they are big enough to get a full tail on their stern.
> 
> The real problem is ASW weapons on such small crafts: Nowadays our primary weapon is the Mk46 torp and that plus the launch tube would be pretty heavy and cause stability problems.
> 
> Question is, really, why would we want to do that? For harbour approaches, much better to deploy fixed bottom ASW sonar nets monitored from shore and then use a helicopter for prosecution.



The nets I can see, but a an operating helicopter in Canada 24/7, that's a stretch.. ;D

Using small ships with a bigger one was quite common for harbour defence from subs in WWII. If the threat became real there would be a significant lag in proper defences being prepared and I could see this happening.


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## Cdn Blackshirt (23 Sep 2014)

SeaKingTacco said:
			
		

> Why would you want to get a ship (any ship) within torpedo range of a submarine?
> 
> The whole of point ASW is get the sub, without that happening.



Without getting into classified details, how hard are the latest generation of enemy submarines and also torpedoes, once fired, to detect?  It sounds like from your viewpoint that even so-called ASW ships should avoid direct contact as the advantage lies with the submarine in that scenario.


Thanks in advance, Matthew.


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## SeaKingTacco (23 Sep 2014)

Basically, if you let a submarine get within mk46 range of your ship, you are now fighting for your very existence. The submarine's torpedo is much longer ranged and the submarine has the advantage in terms of knowing the water column better.

If you are going to go the small ASW ship route, you need to give it some sort of standoff weapon.


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## Oldgateboatdriver (23 Sep 2014)

SKT is absolutely right on this one: From a ship's position, you want to hunt and prosecute enemy subs outside their firing envelope, which is greater than yours. And I say firing envelope because it is not just torpedoes we have to worry about these days - most hunter-killer subs can fire anti-ship missiles too.

So, small ship with standoff weapon ASW? Something small, real fast, shallow draft? Are we talking about an updated BRAS-D'OR with an Ikara mounted Mk46?


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## Colin Parkinson (23 Sep 2014)

In a harbour defence scenario you may not have that option, neither Vancouver or Esquimalt offer the option to stay out of range. On the plus side the subs would not want to lose surprise by attempting to destroy a small vessel. The attacking sub primary mission may be to lay mines or bring small manned subs for attack purposes. Attacking the patrol vessels prior is not going to help as the sub is hindered as well.


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## Kirkhill (23 Sep 2014)

What happens to "small vessel" capacity (less than 1000 tonnes) if we were to produce SWATH or Catamaran platforms?

Catamaran = JHSV at 1500 tonnes (so a smaller scale version)







SWATH = SeaFighter at 950 tonnes






SWATH article


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## Baz (23 Sep 2014)

Oldgateboatdriver said:
			
		

> If you want to be cute, fitting the Orca's with a helicopter dipping sonar over the stern would be an easy mod.



Probably wouldn't work... helo dipping sonars are sensitive to being dragged.  It doesn't actually take much dragging to actually broach an AQS-13 (aka AQS-502, what the Sea King has).


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## Kirkhill (23 Sep 2014)

Isn't the ASROC Mk46 limited in range (<20 km)?

How about slinging a Mk46 and some sonars under Northrop Grumman Jetranger 407 (Firescout MQ-8C)?






I know we are outside the Orca range - but we are still in the Kingston envelope if you look at the SWATH/Catamaran solutions.


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## Colin Parkinson (23 Sep 2014)

But that's similar to what the Italians did, several small boats dipping sonars in while one attacked. I was thinking more along the lines is what can we do now or in the next 10 years with what we have if a sub threat arises?


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## Ex-Dragoon (23 Sep 2014)

I wonder if fitting a Kingston with 2 different families of UUVs might be a solution? Have UUVs operate in hunter/killer pairs, one would be a hunter platform fitted with sensors  the other would be killer as a big depth charge or 1 or two torpedoes?


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## Colin Parkinson (23 Sep 2014)

Even smallish motor yachts equipped with small Hedgehog array would be a threat and with a depth disable, not interfere with the active sonar. A bowpicker Gillnetter would work, fast, frontal deck space. GPS guided to target area with orders given by the command vessel.


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## GK .Dundas (23 Sep 2014)

Colin ,
 I think I have your  Hedgehog replacement 
http://www.youtube.com/watch?v=6rXc9FUGfEU


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## Colin Parkinson (23 Sep 2014)

Pretty much, but we really need the Flashing sign "Submarine Spotted"   :nod:

The goal of the harbour defence is to make the likelihood of a close in attack or surveillance succeeding very unlikely. It would also free up the big ships for escort duty and Hunter Killer teams


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## GK .Dundas (23 Sep 2014)

Colin P said:
			
		

> Even smallish motor yachts equipped with small Hedgehog array would be a threat and with a depth disable, not interfere with the active sonar. A bowpicker Gillnetter would work, fast, frontal deck space. GPS guided to target area with orders given by the command vessel.
> Is this what you`re thinking of , Colin
> http://www.pacificboatbrokers.com/images_all.asp?File_Number=NF4374


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## GR66 (23 Sep 2014)

Harbour defence aside as a specialty, I think for ASW it makes sense to have a larger number of smaller (i.e. cheaper) platforms over a smaller number of expensive platforms.  In case of war vs. a major power then the key goal of Western navies will be to allow the US to deploy its military forces wherever they are needed.  A key objective of our adversary will be to prevent the US from being able to deploy its forces. 

To my mind that means that having a relatively large RCN fleet with ASW and MCM capability to hunt for the needles in haystacks that are enemy subs and potentially asymmetrical naval threats (civilian cargo ships laying mines, sonobuoys, UUV's, etc?).  I'd think you'd want the ships to at least be large enough to deploy a MH or their effectiveness/engagement range is really limited.  However I'd go for the smallest, cheapest ship you can have with a towed-array, a hanger and an ASROC.  Maybe one-vs-one on an enemy sub you might be more likely to lose the fight than a larger, more capable ship, but it would allow you to have more platforms and cover more area.  And the cold, hard truth is that forcing a sub to expose it's position to engage a cheap and plentiful ASW escort may strategically be better than losing the high-value transports/carriers/etc. that it is protecting.


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## Colin Parkinson (24 Sep 2014)

Coastal and harbour vessels won't need a hanger as they can get air support easily. I agree with your points, for the harbour defences you are looking at small picket boats and small support boats for AUV/ROV ops (30-50') ASW Attack boats would be in the 110' range (think Fairmiles) Beyond them would be the vessels like the Kingston Class and then hand off to open water to the bigger vessels.

Seniers and Trawlers can be easily retrofitted with towed arrays and have the electrical and hydraulic systems to support them already. 

At least we don't have to worry about subs with deck guns. The number of stowed kills in a sub is likely less than the WWII equivalent (although each torpedo is much more likely to succeed)


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## Navy_Pete (27 Sep 2014)

Silly question, but rather then getting a sub into our harbour, wouldn't it make more sense to stand off somewhere and simply launch a few ICBMs or other long range missiles from said sub at the city in question?  Seems like the naval equivalent of putting down your high calibre rifle to go poke a bear with a stick instead.


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## Colin Parkinson (29 Sep 2014)

Granted that is more of a threat now, but if you don't have the defences, then people might be tempted to try and I suspect there are not as many cruise missiles in anyone stocks for all of the targets. Not to mention a delayed action mine or explosives planted and then having the sub slip away provides some unaccountability, such as the games NK plays. The target may not even be a big sub, but a smaller sub delivered into the area by a disguised merchant ship.


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## GK .Dundas (29 Sep 2014)

Colin P said:
			
		

> Granted that is more of a threat now, but if you don't have the defences, then people might be tempted to try and I suspect there are not as many cruise missiles in anyone stocks for all of the targets. Not to mention a delayed action mine or explosives planted and then having the sub slip away provides some unaccountability, such as the games NK plays. The target may not even be a big sub, but a smaller sub delivered into the area by a disguised merchant ship.


Some years back an RCN officer wrote an article for ........Broadsides I think about using seaborne IEDs to close a port.Using old hot water heaters as a shell. 
It strikes me that a rogue state such as North Korea would be such as a user of this method.


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## Colin Parkinson (29 Sep 2014)

Weren't the Germans running operations from an interned freighter in Spain against the British held Gibraltar?


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## GK .Dundas (29 Sep 2014)

Colin P said:
			
		

> Weren't the Germans running operations from an interned freighter in Spain against the British held Gibraltar?
> [/quote
> There was  one vessel acting as a intel post in the former Portuguese colony of Goa as mentioned by James Leasor in his book Boarding Party . I believe the Italians  had a similar operation against Malta .


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## Kirkhill (29 Sep 2014)

http://en.wikipedia.org/wiki/British_commando_frogmen
http://en.wikipedia.org/wiki/Human_torpedo







Judging from accounts the assaults weren't particularly successful and had a high loss rate among the assaulters.

These days I am guessing that gliding UUV-mines capable of sitting on the bottom would be a better bet.


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## a_majoor (29 Sep 2014)

It seems to make more sense to break the problem down into two parts: detecting the enemy sub and then prosecuting it.

Several "packaged" sonar systems have been demonstrated to operate in a modular fashion off ships and platforms as varied as the "Sea Slice" (a form of SWATH ship) to versions of the Littoral Combat Ship, so putting a compact and self contained sensor package on a ship (or boat, for that matter) does not seem to be a problem. Since we ideally want to have lots of sensors in a picket line to make it hard for the sub to approach, I would think a series of robotic ships or boats that can carry and deploy the systems under control of a larger vessel (or even a shore station if conditions permit) would make sense. Once the submarine has been identified and an alert given, then whatever ship, aircraft or helicopter that is best placed can be given the coordinates and the job.

Harbour defense is a lot harder, since the distances are so close and the timelines are far shorter. OTOH, I doubt the submarine wants to get too close in anyway (think of the Soviet sub stranded off the coast of Sweden many years ago when it ran aground). Even if it is dropping off a SEAL team or Spetsnaz swimmers, it can stand off some distance while they approach using underwater sleds, mini subs or whatever special forces shiny kit is being used now.


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## quadrapiper (29 Sep 2014)

Would a mini-SOSUS net off the harbour mouth be of value?


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## Colin Parkinson (30 Sep 2014)

I believe late war that hydrophones were set up off of Prince Rupert. Certainly fairly easy to do, must be mind numbing to sit in a shack hour upon hour listening to seal farts.


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## GK .Dundas (30 Sep 2014)

Colin P said:
			
		

> I believe late war that hydrophones were set up off of Prince Rupert. Certainly fairly easy to do, must be mind numbing to sit in a shack hour upon hour listening to seal farts.


 
 That's why computers why computers were built just for those pointless mind numbing near useless jobs......well that and 2nd Lieutenants.


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## Navy_Pete (30 Sep 2014)

Do they not already have a few solutions for running a series of sonar arrays along the sea floor?  It should be easy enough to do, and give you the option of passive/active.  I think the also have unmanned underwater sonar drones they can drop in anywhere with a variety of programs, that will come up to the surface and transmit if they get a target.


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## a_majoor (10 Oct 2014)

Small remote warships come closer to reality. Small ships like this could be patrolling around a harbour mouth or a task force at sea deploying sensors and acting as small weapons platforms to confront a large array of threats at a distance from the target:

http://www.wired.com/2014/10/navy-self-driving-swarmboats/



> *The Navy’s Developing Little Autonomous Boats to Defend Its Ships*
> BY JORDAN GOLSON   10.06.14  |   6:30 AM  |   PERMALINK
> 
> An unmanned 27-foot harbor security boat from Naval Surface Warfare Center Carderock operates autonomously during an Office of Naval Research (ONR)-sponsored demonstration of swarmboat technology held on the James River in Newport News, Va.
> ...


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## a_majoor (29 Mar 2015)

Coming at the problem from the air, DARPA is working on options for small ships to carry and utilize UCAVs. While they will initially be sensor platforms, there is nothing to stop them from being used to drop sonar bouys, utilize very small, lightweight dipping sonars or even prosecute a target with a small hedgehog type charge (while a Hedgehog might not damage or kill the sub, it certainly will change any calculations by the sub's crew about the mission):

http://nextbigfuture.com/2015/03/darpa-progress-to-small-ships-with.html



> *DARPA progress to small ships each with UAV air forces*
> air force, darpa, drones, navy, robotics, ships, technology, UAV
> 
> DARPA has chosen two performers to work on new systems that would cost-effectively provide capabilities on par with land-based systems.
> ...


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