Guide to Republic of Singapore Navy Formidable class stealth frigate upgrades: Mast and upper works

Bespoke: The Republic of Singapore Navy's multi-role stealth frigate, RSS Tenacious, displays upgrades which make her unique among six Formidable-class warships. The modifications tailor her for OOTW missions such as those performed by sister ship Intrepid in the Gulf of Aden's piracy-prone waters in late 2012.

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Last week's Republic of Singapore Navy (RSN) Navy Open House allowed visitors to see three versions of upgrades to Formidable-class stealth frigates (FFS).

Whether or not you were there to see the upgrades for yourself and regardless of how familiar you are with this class of 114-metre long warships, this guide will present a virtual tour of changes to the upper works of the Formidable-class vessels.

The three FFS displayed at NOH were:
RSS Intrepid (69) - Modified for Operations Other Than War (OOTW). First FFS sent for anti-piracy sweeps in the Gulf of Aden under Operation Blue Sapphire (Maritime). Twin Harpoon SSMs on front and rear of the three missile mounts on the SSM deck.

RSS Steadfast (70) - Displayed multi-role FFS configuration for conventional hot-war maritime scenarios. This is the baseline FFS configuration. Twin Harpoons on the centre of three missile mounts.

RSS Tenacious (71) - Latest evolution of the FFS OOTW evolution. Bespoke equipment fit based on the one for ITR with refinements thought to have been recommended by the OBS(M) after-action review. Quad Harpoons on the front and rear of three missile mounts on SSM deck. Own seaboat placed in RHIB station amidships to demonstrate where Singapore Armed Forces Special Operations Task Force RHIBs would be embarked.

The anti-ship missile configurations showcased by Fleet RSN point to the following:
1. Anti-ship missiles can be fitted on all three missile stations port and starboard.

2. Harpoon missiles can be double stacked to form a quad pack (as seen on TNC). This indicates a warload of 24 Harpoon SSMs, giving Singapore's six Formidable-class multi-role stealth frigates an anti-ship warload that is unrivalled by other frigate types and almost every class of destroyers and even missile cruisers.

If the Full Force Potential of 185 Squadron, the RSN's FFS squadron, goes out to sea, the six warships could potentially embark 144 Harpoon missiles.

Assuming four missiles are kept in reserve for ship self-defence and one FFS deployed close to Singapore Territorial Waters to add her Aster 15s for sea-based air defence, a missile strike by just five Formidables could bring into play up to 100 Harpoons fired in a coordinated salvo (Unlikely as this is a gross overkill. There is nothing afloat that can absorb and survive an attack by 100 Harpoons at one go. The ROI can still be achieved with fewer birds launched) or launched at intervals in sufficient numbers and with varying flight profiles to saturate the target vessel(s) defensive aids.

The sizeable anti-ship missile armament allows many permutations to the missile strike end game, including having Harpoons converge upon the target from multiple compass points at the same time. This almost guarantees a hull rupture, even after granting the target the concession of downing some Harpoons that are part of the strike package.

The effectiveness of the FFS missile strike is multiplied when time over target is coordinated with action by friendly air and submarine assets.

Coming back to improvements made to the FFS, let's turn our eyes to the warship's structure above the waterline.  

Among the visible changes to upper works, changes to the FFS electro-optics (EO) ball, which combine images captured by powerful optics and range finders on the operator's electronic screen (hence its name) and non-lethal hailing devices like the Long-Range Acoustic Device 500 Xtreme (LRAD 500X) indicate how the FFS baseline design has been adapted for OOTW.

Fire control radar

Here's Steadfast (above) with the baseline configuration for bridge roof and main mast. Compare the image above with the one for Tenacious (below).

The fire control radar (FCR) fitted onto the bridge roof is new. The FCR was initially thought to be the Thales STIR model but was subsequently identified as the Thales STING. The device, which is slaved to the warship's OTO Melara 76/62 Super Rapido main gun, can calculate fall of shot and can also be used for long-range observation of contacts of interest with radar cold.

New location for EO sensor & mast modification
As the EO ball was displayed by the new FCR, warship fans who love to look for lumps and bumps on RSN surface combatants may have been thrilled to see the new EO perched midway up the main mast. Can you spot the EO in the image above and below?

The EO's high perch gives Tenacious the abilty to see farther as the EO's visual horizon is extended compared to a lower placement. It is thought to give an unobstructed 180-degree view in the warship's direction of travel. However, questions arose on whether Tenacious can service the EO's viewing glass should it be obscured while underway (by seagull poo, for example).

The image above shows another feature thought to be unique to TNC - an extended horizontal arm on the main mast which makes the portion to starboard asymmetrical. It is thought that the extension of the horizontal arm was necessary to place undisclosed sensors in a position with minimal electro-magnetic interference with other sensors on the mast.

The 25mm Typhoon gun mounts found on the RAS decks of both ITR and TNC are further giveaways to whether one is looking at the baseline hot-war configuration or the bespoke OOTW evolution.

Two unknown structures on the hangar roof (you may like to read the earlier post on WASS C310 anti-torpedo decoys...) is proof that Fleet RSN and Singaporean defence engineers have been kept busy ensuring the stealth frigates can dish it out and take it during high intensity naval action.

Tips for defence buffs:
1. When it comes to SAF equipment, never assume you've seen it all just because you've seen it once.

2. Meticulous and sustained documentation will help uncover unannounced mods.

3. Familiarise yourself with the baseline configuration of any weapon platform or system. Such product knowledge will make new stuff stand out.

4. Observe at close range.

5. Shoot everything. Twice.