Author Topic: Frigate Acquisition Project: Towed Sonar Array  (Read 5788 times)


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Frigate Acquisition Project: Towed Sonar Array
« on: September 28, 2016, 03:42:30 PM »
Administrator's note: See also Frigate Acquisition Project thread index for this, and other, sub-systems


The SBB for the PN Frigate program that Herbie had the following entry on page 6:

Fitted For But Not With (FFBNW) . . . for a sonar array

While the FFBNW approach for VLS made ballast control interesting . . .

. . . it would arguably be even more so with a towed sonar array with all the weight associated with the winch system and cables associated with it.

For reference, here is an excerpt from Horge's research about what it would take to add a similar system to the PF-15

Quote from: horge on June 26, 2011, 10:50:12 PM
I can't find EXACT dimensions for an OK-410 and its peripherals, and ultimately:
there are many other towed-array sonar systems besides AN/SQR-19 TACTAS, with their
own handling-winch dimensions. Size means cable length and effectiveness of the TAS.

Here are some photos that give an idea of the sizes of just the TAS handling-winch:
(wala pa ang other components represented in the image I posted earlier)

Indal Tech's array handling winch. Note the man for scale.

An Appleton Marine array handling winch. Note the ladder for scale.

The massive handling winch for the DUBV 43C towed-array sonar on the
French ASW frégate La Lamotte-Picquet Note the crewman for scale,
and realize the rest of the system (just for handling the cable) is forward
and/or belowdecks of the big winch.


One of the larger torpedo-detection TAS systems (ULTRA TRAPR) has a
smaller handling winch, typical for such systems, since they have much
shorter tow cables. Note crewman at top right of image, for scale


The following highlights the weight of all this gear

Quote from: horge on July 02, 2011, 09:03:49 PM
To be clear, we're not supposed to consider systems that are unavailable
in aceeptable ASW configuration, lol... but WTF:  :lol:  :lol:  :lol:

The QH-50 would have to be developed further to haul a heavier payload.
In our case, an ASW-UAV would (IMHO) have to possess dipping sonar, a
secure datalink w/ PF-15, and an anti-sub weapon. That would be its
effective payload:

AQS-18 transducer, cable, winch, etc. -- 265kg
MD-2202 datalink and peripherals -------  11kg
Mk. 46 torpedo ------------------------ 231kg
Cobalt 90 FLIR turret and peripherals -----  2kg
RDR-1700b radar ------------------------  50kg

That's over half a ton of gear.
QH-50 at best could only haul a bit more than 390kg (pair of Mk.44).
Picador supposedly can carry 180kg. Eagle Eye & Fire Scout, 90+kg.

« Last Edit: April 05, 2018, 12:59:45 PM by adroth »


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Re: FFBNW: Towed Sonar Array
« Reply #1 on: September 28, 2016, 03:44:11 PM »
Copying Horge's post from a cache

My LFATS pimpage was perhaps more relevant, fam.

Quote from: horge on August 20, 2012, 02:58:55 AM
Some recent chatter about sonar for PF-15 (GdP)...
so I'll necro-add two data points:

The SQS-56 active hullmount that Chuck was mentioning as a possible upgrade to PF-15
allegedly cost about US$4.5 Million in 1988 (Friedman 2006:674, likely based on Turkish
orders for their Meko-200's). Inflation-adjustment to get a 2012 price in this case would
be misleading, since EDA prices are a whole other matter, but pro-forma, that'd be about
US$8.6 Million if built new today. It is again, unclear whether any EDA stocks are there
to be had by PN, for any amount of money.


A new active, towed-VDS from L3 Communications, the diminutive LFATS VDS-100 (about
1/4 the size of other comparable-performance systems) may be suitable at PF-15's stern,
assuming the stern Mk.38 isn't too much in the way, and the fish-deployment boom can
be separated from the spool somewhat (so everything but the boom can stay under the
shelter of the FD). The system weight is a little bit more than 5.5 metric tons. An Egyptian
order in 2010 (valued at over 24 Million) suggests a unit cost of over US$ 4 Million. [1]

It is worth noting that LFATS was specifically conceived in part as a replacement for the
AN/SQS-56 and AN/SQS-53.

The small size of the system is evident in photos:




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Re: FFBNW: Towed Sonar Array
« Reply #2 on: September 28, 2016, 03:46:07 PM »
Posts from Chuck Hill and Horge copied from cache

Quote from: Chuck Hill on February 12, 2016, 08:23:46 PM
You might want to look at Thales CAPTAS for more modern systems. They are currently marketed in three different sizes. Most are the larger CAPTAS 4, but there are also two smaller versions, CAPTAS 1 and 2.

THALES' CAPTAS is indeed quite an impressive family of towed-VDS systems, CDR Hill.  :)

image: THALES

If we take the CAPTAS model closest-comparable to LFATS VDS-100, and compare stats...

The LFATS VDS-100 weighs 5.5 tons and suits vessels as small as 70 tons of displacement.
With a winch-and-handling footprint of roughly 16 sq.m., the manufacturer (L3) claims active-only
detect range in excess of 48km.[1] LFATS VDS-100 seems to be designed with an eye toward
ease of installation onto an existing vessel that did not have towed-VDS prior.

The CAPTAS-1 weighs 8 tons and is suitable for vessels as small as 300 tons displacement.
With a winch-and-handling footprint of roughly 8 sq.m., the active/passive CAPTAS-1 is specified
by its manufacturer (THALES) to achieve detection range of up to 30km.[2] The THALES CAPTAS 
family of towed-VDS has a very impressive client list, including the Royal Navy, Marine Nationale,
Marina Militare, and the United States Navy for its LCS).

...we see adroth's point underlined: even the smallest towed-VDS systems present sgnificant
weight and space considerations. More importantly, such weight and space considerations
will vary considerably from one potential system to the next.

Trying to leave a design-allowance, in an FFBNW context, for such a wide range of spaces and
weights can lead to inefficient design at minimum, and/or to compromised sea-handling at the
near-worst (although the sea-handling issue can be addressed via substitute ballasting).

In fact, going the FFBNW route in sonar spec for a FFG can lead to farce, where the client/buyer leaves
the specs of the future sonar system vague. Bid proposals typically will involve already-prepared vessel
designs, which often-as-not will be optimized for a specific brand/model (!!!) of towed-VDS, in which case
the client/buyer might as well have just specified (and acquired) said towed-VDS model from the start.
However, non-specific vagueness isn't what we see in the PN Frigate bid wrt towed-VDS, is it?

As Chuck Hill has pretty much alluded to, and many others have pointed out prior, the frigate bid that this
thread deals with has a FFBNW specification for towed-VDS, in terms of size and weight, that is practically
copy-pasted from THALES' spec for CAPTAS-2 (!!!), which leaves me wondering: why the heck didn't
PN (DND-BAC, really) just outright specify CAPTAS-2 as the intended VDS explicitly, from the very start?
(Yes, yes... I know why the spec is the way it is... but I reserve the right to whinge about it.)

Compare this:

with this:
The CAPTAS 2 sonar TB is 2x1x1.2 (LxHxW) meters with a weight of 1,250 kg.
The towed array is 90 meters in length and 85mm in diameter with a combined weight of 2,490 kg.
The handling system is 6.4x2.1x4.4 (LxHxW) meters with a weight of 15,000 kg..."[3]

All of ^that aside, for me the real problem with FFBNW-specification of sonar lies in the resultant,
potential issues of systems-compatibility/integration, tied to long delays in filling out FFBNW gaps:

Where towed-VDS is specified, complementary hullmounted sonar tends to also be prescribed, to
allow the shorter-range and more-precise detection (up to 18km) which towed-VDS systems don't,
generally speaking, readily address.

Desirable multistatic compatibility with ASW helo sonar --whether dipping or sonobuoy-- and
general compatibility with hullmounted sonar, tends to mean that WHEN one specifies and
acquires the ASW helo with its heliborne sonar (sonobuoy or dipper), it is most prudent to ALSO
spec/acquire the towed-VDS and hull-mounted sonar at the same time, so as to GUARANTEE
the fullest compatibility, integration, and OEM support.

What happens when the towed-VDS model you (implicitly) specced goes explicitly out of production?
Given DND/AFP's dodgy track record with filling out FFBNW gaps down the (typically very long) road...
this is a valid concern.

[1]  Fish, T : "On The Pulse" : Digital Battlespace (May/June 2012) vol, 4 no. 3 : 158

[2]  (see graphic above, from THALES)



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Re: Frigate Acquisition Project: Towed Sonar Array
« Reply #3 on: June 05, 2021, 03:05:25 AM »
A lot of the links previously posted unfortunately no longer exist, so I felt I might as well chime in and post some updated links to information on some of the systems mentioned and others as well. I'm including alternate links for the brochures/datasheets just in case.

Thales CAPTAS webpage
CAPTAS 1 brochure [Archived]
CAPTAS 2 brochure [Archived]
CAPTAS 4 brochure  [Archived]

L3Harris LFATS
L3Harris LFATS brochure  [Archived]
L3Harris Model 980
L3Harris Model 980 brochure  [Archived]
L3Harris Orion
L3Harris Orion brochure [Archived]

DSIT Solutions Swordfish
DSIT Solutions Swordfish brochure [Archived]

Atlas Elektronik ACTAS
Atlas Elektronik ACTAS brochure [Archived]

Ultra Sea Lancer & Sea Sabre

Some other vendors with not much information available:
General Dynamics Towed Array Sonar
GeoSpectrum Technologies Towed Array Sonar
« Last Edit: June 05, 2021, 02:13:04 PM by girder »