Trinity House’s Rapid Intervention Vessel (RIV) Alert has been designed with buoy handling, wreck marking, towing, multibeam and side scan hydrographic surveying capability. With DP1, high specification survey equipment and a maximum speed of 17 knots, Alert is deployed primarily to cover the South East Coast where she can respond rapidly to any maritime incident.

In addition, with her large working deck and 0.6m diameter through hull instrument tube, she is an ideal research platform for deployment of scientific equipment and sampling work. Available 24/7 with accommodation for an additional 4 people, Alert can be utilised for a wide range of projects at very competitive rates.

Available 24/7 with accommodation for an additional four people, THV Alert is a state of the art vessel that can be utilised for a wide range of projects at very competitive rates including:

  • hydrographic surveys including bathymetry, side scan, sonar and wreck investigations
  • aids to navigation deployment, maintenance, repair and examination
  • research platforms for deployment and recovery of scientific equipment
  • sampling projects
  • marine hazard search and marking
  • lifting, towing and accurate positioning of marine equipment
  • recovery and re-establishment of off-station aids to navigation
  • sea trials of electronic and specialty equipment
  • helicopter support
  • safety boat assignments
  • guard duties for cable and pipe laying projects

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Build Standard

100 A1, SSC Workboat, Mono, LA, EP, LMC, UMS, DP (CM)

Descriptive note: Shipright (MPMS, SERS, IHM)

Complies with requirements for UK MCA Class VIII vessel.


Port of Registry London

Year of Build 2006

Call Sign MLPH9

Length Overall 39.3m

Breadth Moulded 8.0m

Depth Moulded 4.0m

Draft 2.7m

Air Draft 18.0m

Maximum Speed 17kts

Service Speed 12kts

Fuel Consumption at 12 kts 360ltrs/hr

Bunker Capacity 42t

Fresh Water 12t

Endurance 1,500nm @ 15kts / 3,000nm @ 12kts

Endurance 5 days working on site

Bollard Pull 28t


Main Engines – 2 x Caterpillar Diesel 1492 kW @ 1600 RPM

Auxiliary Generators – 2 Caterpillar C90 Diesel 155 kW @ 1620 RPM

Bow Thruster – HRP 155kW @ 1620 RPM

Propellers – 2 Kamewa variable pitch 50 XF5/4

Running on BIOGEAR XP Environmentally Acceptable Lubricant (EAL)


Kongsberg C-Pos LR DP (CM)


RIB 5.4m 50hp


Palfinger Knuckle Boom –

3.5t @ 10m

2.2t @ 15m

Winch 3.3t SWL


Chain Capacity 100m x 38mm

Max pull 40t


Main Deck Area – 88m2

2 x ISO 10’ Container Lock Down Matrix

Electrical Power – 230V and 400V Supplies

Pressure Wash – 350bar/5000psi

Through Hull Instrument Tube – 0.6m diameter

Hold – Storage & workshop


Single Cabins: 2

Twin Cabins (Bunks): 4

Crew: 6

Spare Berths: 4

Mess Room: 1

Changing Room: 1

Showers: 2

Toilets: 3


Multi beam E/S – Kongsberg Simrad EM 2040C

Echo Sounder – Kongsberg Simrad EA 400

RTK Pos MV Oceanmaster RM

SVP – Valeport Modus (Fixed Unit)


Sonar – Simrad SL 30/35

Side Scan – Simrad GeoAcoustics


GMDSS Area 2

Satcoms – Sat-C H2095C

Iridium – Sailor ST4110

MF/HF SSB – R/T DSC Sailor CU5100

Navtex Rx – Furuno NX700

VHF R/T DSC – 2 x Sailor RT4822

VHF – Sailor RT6210

Internet Access – All cabins


ECDIS/NAV – Sperry Marine

Radars – Vision Master FT

  • Sperry Marine Vision – Master FT X-Band
  • Sperry Marine Vision – Master FT S-Band

Dual-Axis Speed Log – Consilium SAL SD4-2

DGPS – 2 x Litton Marine LMX 420

Gyro Compass – Sperry Navigat Fibre Optic

TMC Magnetic Compass – Sperry Navipol 1

Auto Pilot – Sperry NaviPilot 4000 l

Echo Sounder – Sperry ES 5100-01

Download full specification for THV Alert [PDF]

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