Sunday, June 2, 2013

Ship without joy: The Republic of Singapore Navy target vessel Jolly Roger

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To our weapons development teams, defence engineers and test pilots. Thank you for the work that you perform and the responsibilities you shoulder. May your stories be told some day.

The first part of this post is opinion based on present-day observations. The rest is fiction - leave you to decide which part may have actually happened. :-)

Impact zone: You wouldn't want to be on the deck of the target ship Jolly Roger II when the Singapore Armed Forces conduct guided weapons trials using her as the aimpoint. The original Jolly Roger is rumoured to have been sent to the bottom of the South China Sea by Paveway LGBs dropped by the Republic of Singapore Air Force.
Singapore is among the few countries in Southeast Asia with defence technology know-how that can customise off-the-shelf weapon systems and platforms for its specific operational requirements. Special vessels like the Jolly Roger II serve a vital role in such efforts.

Ignored during a public event, she is a bomb missile attention magnet during secret military trials. The Republic of Singapore Navy's target ship, Jolly Roger II, leads a life of striking contrasts.

Virtually ignored at the Singapore Navy's largest public event, the Navy Open House, Jolly Roger II becomes the centre of attention during Singapore Armed Forces (SAF) guided weapon trials, most of which are classified secret and above.

Modified from a barge design with inputs from Fleet RSN, Ministry of Defence (MINDEF) naval architects designed Jolly Roger II to resemble a typical fast attack craft (FAC) of no particular design (or nationality) with a notional gun turret forward, a superstructure and mast and assorted structures aft.

Her "gun turret" has no barrel, her "bridge" is windowless and being unpowered, a pufferfish could outswim this floating curiosity. But her shape is about right and when an active radar seeker is locked on to Jolly Roger, the radar return is said to closely mimic that of a FAC.

The target barge is the only surface vessel in the RSN painted in three colour paint scheme of white, black and grey and has more anchors than any other man-of-war in Fleet RSN. Numbered markings on her hull help Singaporean defence engineers calculate the effectiveness of weapons trials, particularly the centroid for radar-guided munitions.

She has been attacked relentlessly by live ordnance on more occasions that any other RSN surface vessel, sometimes almost to the point of destruction. Point detonation, delayed action, proximity fused, sea skimming at wave top height, sea skimming with pop-up terminal dive, glide bombs, dumb bombs, smart munitions delivered by naval or air force war machines - the punishment that Jolly Roger II has endured probably makes her the most miserable ship in the Singapore Navy.

Jolly Roger II will never be named Best Ship. She is a ship without joy, but she is lucky.

Despite the ferocity of attacks unleashed by the SAF, Jolly Roger is virtually "indestructible" because the Singaporean Ministry of Defence (MINDEF) will pay to have her rebuilt every time. These unpublicised trials allow MINDEF/SAF to customise guided weapons for the SAF's specific operational requirements, to make bespoke ordnance that countermeasures cannot fool and which give Singaporean warfighters something special to wield against hostile forces.

Indeed, guided weapon trials are so important to MINDEF/SAF that money was spent rebuilding Jolly Roger whereas the hulk of the Anti-submarine Patrol Vessel RSS Courageous was never made seaworthy again.

That rebuild was necessary, thanks to the Republic of Singapore Air Force (RSAF) which sent the original Jolly Roger to the bottom of the South China Sea decades ago during guided weapon trials which cleared the upgraded Northrop F-5S for the maritime strike role using Paveway II laser-guided bombs.

One can only imagine what could have happened.

First aloft was a E-2C Hawkeye from the RSAF's 111 Squadron.

The airborne early warning (AEW) turboprop would play the role of range warden this tropical morning by using her saucer-shaped radar to check the exercise area for air and surface traffic that should not be in the area.

Inside the Hawkeye's cabin, air force radar plotters noticed that a fixed datum marked on their PPIs was constantly circled by surface vessels and a large mothership. The surface vessels moved in elliptical race track patterns while the large blip appeared happy to mark time at a slow rate of knots.

That fixed datum was their contact of interest: the Navy's target ship Jolly Roger. Surface contacts circling her were Missile Corvettes (MCVs) from the RSN's 188 Squadron. They too were range wardens and were tasked to sanitise the area of underwater contacts (i.e. foreign nation submarines).

The large blip was an Endurance-class tank landing ship, configured as exercise control for the trial involving 500-pound GBU-12 laser guided bombs that were en route from Paya Lebar Air Base. Also wandering aimlessly in the vicinity (but maintaining a respectful distance from the target ship) was an ocean tug which towed Jolly Roger all the way from Bravo Whisky to one of the grids in the the South China Sea Delta area.

The MCVs had their fish out for some time and both Commanding Officers had their warships closed up for action stations.

With Variable Depth Sonars systematically pinging the depths around Jolly Roger, ASWOs aboard the MCVs scrutinised the sonar returns tell tale signs of underwater objects. There was nothing found (which should be the case) and the underwater situation picture was clear.

The MCVs continued on their assigned sector search pattern towing their VDS at the stern with an umbilical cable that connected warship to underwater sensor tens of metres beneath the missile boats.

The MCVs could not see the RSAF Hawkeye circling high over the exercise area. But the air situation picture compiled by the Sea Giraffe radars on Valiant and Valour gave Principal Warfare Officers on both ships a good idea of what was in and around the MCVs.

Anchored to the seabed by four anchors, two from the bow and two off her stern, Jolly Roger was not going anywhere.

She was the star of the show and like all stars, commanded attention from cameras and an attentive audience.

If you stood on her deck, you could have seen the hardworking MCVs steaming purposefully in racetrack patterns with their madly spinning Sea Giraffe radars scanning the heavens.

Farther off midway to the horizon to the South of the exercise area, the dark silhouette of RSS Endurance and the tug was a fixture that had stayed in placed for the past few hours.

Defence engineers from the Defence Materials Organisation (this was pre-DSTA) and Naval Logistics Department officers who were the last souls aboard Jolly Roger to check on her battery-powered test equipment couldn't help but notice the picture of serenity while on the barge. A ship at sea is a noisy place with assorted plant and machinery needed to sustain life aboard the ship giving those onboard hardly a moment of quiet. It was so different aboard Jolly Roger.

Before they were taken off by an FCU from Endurance, those aboard Jolly Roger were treated to an unblocked view from horizon to horizon with no exhaust fumes, noisy air vents or diesel engines to disturb the peace.

If this was a pleasure cruise, the sun, wind and water around the Jolly Roger would make this a fine sailing day indeed. Telemetry cameras aboard the target ship showed nets placed on the impact side of her hull barely stir in the soft sea breeze and (almost) dead calm sea. Exercise planners couldn't ask for better conditions to monitor the weapon trial. Alas, that peace and quiet would not last long.

You heard the jets before you saw them. The high-pitched whistle of F-5s with the deep howl of an F404 turbofan from a re-engined TA-4SU Super Skyhawk broke the morning calm as the trio of RSAF warplanes swept across the target ship on a low level, high speed pass.

Jolly Roger's executioners had arrived.

The pair of F-5s comprised a single-seater recently brought up to F-5S standard under Project Mxxxx. On her Number 2 and Number 4 pylons hung blue painted bombed with olive green heads and fins. A centreline tank gave her the legs to make it from her base in Paya Lebar out to the SCS and back again. End to end, the flight would take around 45 minutes.

The F-5F was there as a chase plane and cameraship to film the bomb release and impact sequence. The F-5F led the trio in a echelon left formation: F-5F, F-5S and TA-4SU Super Skyhawk during the flypast over Jolly Roger.

The Super Skyhawk had no ordnance underwing. Two wing tanks on her inboard pylons and a sensor pod on her centreline was her contribution to today's activities.

Flypast over, the trio of warplanes continued their flight across the Jolly Roger from South South West then turned east in a gentle bank.

Inputs relayed by voice from the orbiting E-2 and radio updates from the MCV duo indicated that the range area was clear. This was pre-Battlefield Management System and the air, surface and sub surface situation picture had to be slowly compiled from assorted platforms working alone but connected via secure radio.

If Jolly Roger was the star, the LST Endurance was show central. Here was where the exercise director called the shots and gave his go/no go for the action.

Jolly Roger had attracted a tri-Service audience from the SAF. Uniforms, unit patches and caps from Singapore Army formations, RSAF and RSN squadrons added colour to the hand-picked audience who had gathered to watch the show. There was a good number of civilians onboard too - big guns from MINDEF Level 5 and project engineers from DMO and the Defence Science Organisation. So both sides of the Ops-Tech relationship were well represented.

Satisfied that it was all systems go, the Colonel ordered the RSAF air liaison officer to get the birds into position. The message was relayed by UHF to the orbiting warplanes.

Showtime was about to commence.

With range rings drawn around the Jolly Roger, the idea was for the Skyhawk to illuminate the target using her laser designator while the F-5S glide bombed the ship from standoff range using a pair of 500-pound Paveway II LGBs.

The F-5 would release her bombs several miles from Jolly Roger to simulate a maritime strike delivered at the outer limit of naval anti-aircraft artillery (40mm, 57mm or 76mm) of the simulated threat vessel. Keeping the F-5 well above 10,000 feet simulated an attack posture which would keep the warplane out of reach of SHORADS which, at the time, were appearing aboard regional warships thanks to energetic sales efforts from European missile salesmen.

The trio were now split up. The TA-4 approached Jolly Roger from one compass bearing while the F-5S and her faithful F-5F cameraship flying shotgun ingressed from another bearing. The flying had to be carefully coordinated as the bombs had to remain within a 60 degree cone from the point at which the laser spot hit Jolly Roger.

At a pre-determined range, the F-5S bomb truck called "Ten seconds" to the Skyhawk followed by "Laser On!".

The TA-4 started the show by lasing the target from a standoff distance:"Laser On!"

At the same time, the F-5S pilot turned his switches to "live". The laser spot tracker on his HUD is now hot and the pilot called out "Spot" to indicate that seeker heads on the GBUs have zeroed in on the invisible laser spot on Jolly Roger miles downrange.

Cleared by UHF from Endurance to come in hot, the F-5S rolled into a dive from around 20,000 feet - steep or not is a matter of perception - a manoeuvre which raised the fighter's airspeed to around 450 knots. Bomb release was done at around 15,000 feet to simulate SHORADS avoidance while giving each projectile sufficient KE to reach the impact point.
At that distance miles from impact, it would take a sharp eye indeed to spot the 50-plus metre long target ship amid the slight haze common in the South China Sea at that time of the year.

Weapons release saw both GBUs drop launched from the F-5S milliseconds apart to effect safe separation from the parent aircraft. Relieved of nearly a tonne of bombs, the F-5S pilot felt his aircraft bump upwards twice in rapid succession.

It was time to simulate the evasive manoeuvre after weapons release. The F-5S banked hard right with both burners cooking, leaving the cameraship darting ahead alone to trace the flight of the GBUs to impact.

Egress was done at high speed of around 550 knots - the faster the better - but for this weapons trial, he converted high speed into height by pulling his nose up at 30 to 40 degrees before wingover to recover to level flight. The sleek warplane sought out and joined up with the twin-seat Skyhawk in loose tactical formation. For now, both RSAF war machines orbited the Jolly Roger to observe their handiwork.

Jolly Roger's executioners now became spectators.

The endgame was pretty swift and tidy.

With no explosives in the bomb casings, just ballast to simulate the aerodynamics of a live 500-pound bomb, exercise planners had expected the GBUs to hole Jolly Roger at two places and leave her otherwise undamaged. There would be no heat, blast or destructive shrapnel to damage the target vessel.

At point of impact, the first part of the GBU which struck Jolly Roger was the rod-shaped laser seeker head. Half a tonne of bomb propelled at 400-plus knots from 15,000 feet was at that precise moment transferred to the GBU seeker head, whose extreme end had a diameter about the size of a soda can.

The steel plate of Jolly Roger where the seeker head touched surrendered to the sudden, violent clash of metal. The plate deformed even as the crushing impact destroyed the seeker head, compressing the rod-shaped seeker down to the brain of the bomb which had done its job of guiding projectile to target.

Then came the bomb casing. Several inches thick to maximise sharpnel effect and weighing half a tonne, shaped like an ellipse to minimise drag, the head of the bomb which lay behind the flattened seeker head hit the deck like a battering ram. The initial deformation of the steel, the dent in the deck was pushed to the limit as the steel struggled to contain the energy. It was an exercise in futility.

The GBU punched right through the deck plate, rupturing the deck on the inside of the hull with a flower-shaped pattern as the bomb shot right through the hole, gradually enlarging the hole to the bomb casing's maximum diameter. Once that max diameter had been reached, the rest was easy. The tail end of the GBU met no resistance from Jolly Roger's deck plate and the rest of the bomb casing went straight in, her cruxiform tail fins cutting an "X" shape on the deck as if the steel was putty..

Jolly Roger shook with a second impact as the GBU tore through her hull bottom, creating a puncture wound which vented her to the sea. A jet of seawater surged through the bomb hole, tonnes of seawater fast filling the void in the hull of the converted barge. The air within her hull, compressed by the inexorable inrush of seawater, fought for release. Weak spots in the hull like access hatches that had lost their watertight integrity after years of wear and tear were blasted open by the force of the desperate air bubble struggling to escape.

What was achieved by Bomb 1 was repeated by Bomb 2 as the Super Skyhawk's laser designator worked as advertised. With her hull open to the sea through two bomb holes, Jolly Roger was doomed.

All this took place in milliseconds, too swift for the human eye to catch. That's why highspeed cameras installed by MINDEF defence engineers were there to film the show.[It is rumoured that bomb damage assessment of the sunken vessel revealed bomb entry wounds about the same distance apart as the bombs were carried on the F-5.]

Aboard Endurance, the audience caught the silent movie (cameras were fitted but not microphones) on screens which showed the action unfolding aboard Jolly Roger from several angles.

The takeway from the audience was different, depending on their professional interest in the weapons trial, experience in the weapons business and their calling card.

A Navy Colonel who once commanded an MCV and Missile Gunboat mentally walked through how he would position his ship and the orders he would give to swat that F-5 out of the sky. At around 10km range, his Barak missiles would fly (his PWO would be ordered to launch a pair to ensure a kill). The MCV would show her broadside to the Enemy as that would maximise the arcs of fire for forward and aft Barak missile directors.

If the aerial threat continued its flight, he would turn headon towards the enemy to present the minimum profile. Even as the MCV was repositioned vis-a-vis the threat axis, he would order the 76mm Super Rapid to open fire at around 5km range at max rate of fire of 2 rounds per second. The Oto Melara weapons salesmen claimed the Super Rapid could be used as a CIWS due to its high rate of fire and the FCR's ability to bracket fast moving targets. If it was for real, firing would continue until the threat(s) were destroyed or the magazine depleted.

MINDEF's defence engineers had other thoughts on their minds. They wondered how the slight haze and humidity would affect the laser beam by contributing to atmospheric scatter. Possible lock-on challenges due to divergence of the laser beam or spillover reflection on the sea surface, which could affect weapon accuracy, also occupied their thoughts.

For now, all eyes were fixated on the silent movie as the Ops and Tech reps scrutinised the target for the imminent arrival of the GBUs.

There were the twin bomb impacts - both swift and violent - which rocked the Jolly Roger amid a cloud of rust dust. But hardly any debris flew into the air.

As Jolly Roger settled on an even keel, you could tell things were not right as hatches popped open and the view of the visual horizon from the target vessel's deck changed ever so slightly. If microphones had been fitted, one would have heard the banshee screech of air hissing out from hull fractures and weak weld seems as tonnes of seawater forced its way through the hull ruptures.

Her deck was awash within minutes. Jolly Roger would be a write-off as there was no way the standby tug would be able to tow her back to Brani Naval Base (Changi Naval Base was still a paper plan at the time).

Weighted down by tonnes of seawater, she sank on even keel and disappeared beneath the waves, falling to the seabed with the elegance of a brick dropped into a tub of water.

She was gone even before the RSAF warplanes turned south and set their WDNS for pigeons to home base. For them, their job today was done (for now, more debriefings would follow in coming days).

For MINDEF defence engineers, the job of analysing test results would begin as soon as all telemetry data was compiled for their scrutiny.

Jolly Roger was gone. But a new target ship would eventually take her place: the Jolly Roger II.

Unclassified open source information presented here outlines weapon capabilities of F-5s in general and are not specific to the RSAF. Astute readers should be able to figure things out.


Anonymous said...

A lot of imagination, and a lot of errors. F-5 does not have a laser spot tracker. Egress speed is also way off at 550 knots. You do have a good does of imagination on what really happened. Range safety dictate that you cannot be within the bomb fall template, which means there is no way to train a camera on Endurance on the JR.

And the Skyhawk did not have the laser designator cleared then.

Anonymous said...

Anony 10.44am,
Seems that you are one of those lurking on this blog + a number of defense forums, and you seems to know the story that is written here, if there are areas you really know, can you enlighten us ?


David Boey said...

Dear Anon 10:44 AM,
Self-explanatory visuals added to the Appendix at 10:18 PM 3 Jun'13. We believe they will open your eyes to what the F-5 can do.

re: Egress speed. The fictional weapons drop was based on unclassified material that shows how F-5s would execute a high speed flyby to drop LGBs. The speed of 550 KCAS is within the manual's parameters. Which reference(s) do you cite?

re: Range safety template. Are you aware journalists witnessed live 500-pounders detonate within visual range during Exercise Forging Saber in 2009?

Thank you for sharing your feedback.

Warm regards,


P.S. You may like to check your references about the Skyhawk too.

AL said...

Ah yes what our F5s could do even before the Mxxxx AUP is something many would never know!

And I confirm that David's graphic is very much reality.

Anonymous said...

Commemorating 69th Anniversary of the start of Operation Overlord aka D-Day 06/06/1944.