Merchant Aircraft Carriers for the 21st Century?

[riggerrob]

Could a container ship tow a sonar array?

 

[A_Random_Guy]

Could a container ship tow a sonar array?

No reason why not. They would need additional processing and/or datalink facilities though.

 

[TomS]

No reason why not. They would need additional processing and/or datalink facilities though.

It's going to be insanely loud, though, and towed arrays are very sensitive to ownship noise.

 

[A_Random_Guy]

It's going to be insanely loud, though, and towed arrays are very sensitive to ownship noise.

And would a hull array work better?

The effects of a louder ship on a towed array are variable. Is it a VDS array below the thermocline? How fast is the ship moving (both for propeller noise and for flow noise over the array)?

The exact utility depends on the ship it’s installed on and the employment of said ship. Having an additional array could help with fixing a target for example if operating within a network. It just depends on how many dedicated ASW ships you have (and thus how many you may be in need of) and how effective you need the array to be.

 

[TomS]

And would a hull array work better?

Well, obviously not.

Problem is, you can list all sorts of variables, but the fact is that commerical container ships with no silencing (and probably large low-speed direct-drive diesels) are going to dump a lot of energy into the water and make the sonar's job much harder that it would be from a proper ASW ship with rafted turbines or electric propulsion. Even purpose-built warships with diesels are generally not regarded as quiet enough for towed arrays ops.

Also, consider the normal operating mode for a ship with a towed array is "sprint and drift," alternating low speed phases to listen to the array with high speed dashes to keep up with the formation. That requires quick acceleration and deceleration, which is not at all the hallmark of low-speed diesels. They really don't like throttle slams.

 

[riggerrob]

What if you install one towed array sonar near the bow and a second towed array near the stern?
Would they be able to triangulate the location of a submarine?

 

[TomS]

What if you install one towed array sonar near the bow and a second towed array near the stern?
Would they be able to triangulate the location of a submarine?

Towed arrays are several hundred feet long and are streamed as much as a mile behind the tow ship. Hanging a second one on the same ship isn't generally practical. I'm sure there are exceptions, but in general one tail is all a ship can use effectively. Hydrographic survey ships do things with multiple lines towed in parallel but that's not practical on a warship

 

[A_Random_Guy]

What if you install one towed array sonar near the bow and a second towed array near the stern?
Would they be able to triangulate the location of a submarine?

Towed arrays trail far behind the ship as in up to a couple miles behind the ship. Furthermore the exact length that contains transducers varies between designs. Some are basically a pod or series of pods attached to a cable however most modern designs carry transducers in a continuous line array that can be over 1000 meters long in the case of systems like SURTASS. Some have a separate towed pod that contains an active element to complement the passive array element.

Depending on design, especially with line type towed arrays you can determine distance from just the singular array. One may be able to use the hull array of a ship to check against the bearing found by the array but this is highly dependent on the conditions since sound lenses depending on water temperature, salinity, and pressure, and probably a few other factors I am forgetting so an array deep in the water may be able to pick up a sound but a hydrophone on the surface may be unable to do the same.

A towed array mounted to the bow would be liable to get fouled in the propellers and possibly on the other array. It would be largely redundant though certain systems like SURTASS have a forking "Y" design though this is a bit more niche than general ASW use.