ASW options for small ships and vessels

[Colin Parkinson]

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? 

 

[Oldgateboatdriver]

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.

 

[Stoker]

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.

 

[SeaKingTacco]

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.

 

[Colin Parkinson]

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. 

 

[Cdn Blackshirt]

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.

 

[SeaKingTacco]

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.

 

[Oldgateboatdriver]

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? 

 

[Colin Parkinson]

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. 

 

[Kirkhill]

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

 

[Baz]

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).

 

[Kirkhill]

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.

 

[Colin Parkinson]

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?

 

[Ex-Dragoon]

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?

 

[Colin Parkinson]

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.

 

[GK .Dundas]

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

 

[Colin Parkinson]

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 

 

[GK .Dundas]

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

 

[GR66]

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.

 

[Colin Parkinson]

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)