The Sentinel-class maritime security and response vessels (MSRV) are four refurbished Fearless-class patrol vessels. The first two vessels MSRV Sentinel and MSRV Guardian entered operational service on 26 January 2021, with the latter two MSRV Protector and MSRV Bastion on 20 January 2022. Other than the MSRVs, the flotilla will also operate two tugboats and will operate new purpose-built vessels from 2026. The ships form the Maritime Security Response Flotilla of the Republic of Singapore Navy (RSN).
The refurbishment plan was announced in March 2020 in response to the increase of sea robberies within the region, and foreign intrusions of Singapore territorial waters. In addition to refitting the vessels to extend their operational lifespan, the Sentinel-class MSRVs will be installed with a range of calibrated capabilities. Non-lethal Long-Range Acoustic Device (LRAD) and laser warning systems were added to increase operational flexibility, while fenders were incorporated into the hull to enable quicker operations of suspicious vessels. The forward part of the bridge was also reinforced with ballistic-resistant armor.
The Sentinel-class maritime security and response vessel is 55 meters long and has a steel monohull and V-shaped frames in the forward portions. She has a beam of 8.6 meters, as well as a draught of 2.7 meters. The 500-tonne vessel can cruise with a top speed of 20 knots. These nimble vessels bear red “racing” stripes on their bow, in line with other international maritime security agencies. These vessels create flexibility for the Singapore government and Singapore Armed Forces (SAF) to meet the increased demands from maritime security threats that have grown in scale and complexity.
Four ex-Fearless class patrol vessels have been refurbished as the Sentinel-class MSRVs. The Fearless-class patrol vessels were built by Singapore Technologies (ST) Marine for the Republic of Singapore Navy in the 1990s. Together, the ships formed the 182 and 189 Squadron. In November 2021, ST Engineering was awarded a subcontract for design, platform equipment, and technical assistance by Abu Dhabi Ship Building (ADSB), which is building four Falaj 3-class Offshore Patrol Vessels based on the Fearless class for the UAE Navy.