Yno 241 - Western Trident

Hull No 241 built by Ulstein Verft AS for Western Geophysical a division of Baker Huges, USA

Yno 241 Western Trident

The UT 753 Seismic Vessel is designed by Ulstein Ship Technology AS in close cooperation with Western Geophysical; a division of Baker Hughes.


The UT 753 is developed in accordance with the demanding requirements for silent operation at high capacity seismic production. The vessel is equipped with 16 seismic streamer winches for 3D seismic data acquisition. The vessel features an efficient lay-out, providing a comprehensive arrangement of seismic outfitting, spacious computer processing facilities and a highly flexible, redundant and powerful propulsion and machinery package.


Shipboard and hydroacoustic noise is carefully controlled. All major rotating machinery installations are resiliently mounted, and vibration characteristics of the steel structure and hull are made with minor interference from machinery and propulsion plant. 
M/S "Western Trident" is built with a hotel compliment of high standards and with capacity for 68 persons. Further with a hull integrated helicopter landing platform for Super Puma or or Sikorsky S61.

2017: Not active - IMO 9187502. Owner and manager: Westerngeco, London, UK. Flag: Panama

2021: GC Rieber Shipping ASA has delivered the vessel for recycling in Turkey.


Length over all approx. 92,5 m 
Length between p.p. 80,1 m 
Breadth moulded 23,0 m 
Depth moulded 9,0 m 
Max. draught midship (scantling) 7,3 m 
Max. draught midship (summer) 7,30 m


Ballast water 3136 m3 
Fresh water 446 m3 
Deadweight at summer draught 7,2 m 4568 T 
Gross tonnage, international 8369 GRT 
Net tonnage, international 2511 NRT 
IMO number 8187502 
Call signal 3FEO9


DNV + 1A1, E0, ICE C, HELDK 
Flag: Panama


Speed, approx 15+ knots 
Bollard Pull, approx. 140+ tonnes


The vessel is built with a compliment for totally 68 persons 
Six of one-bed cabins with day room and bedroom 
Eighteen of one-bed cabins 
Fourteen of outboard two-bed cabins 
Eight of inboard two-bed cabins


Deck Cranes 
Two of Deck Cranes, knuckle jib type, 8 T - 14 m
One of Deck Crane, 2 T - 8 m


Rudders / Steering Gears 
Two High lift flap Rudders 
Two Steering Gears


Side Thruster 
One Side Thruster 800TV forward, of 1100 kW


Roll Damping System 
Two Passive stabilizing tank systems


Joystick with three positions in wheelhouse 
Portable joystick for aft deck


Navigation / Communication 
10 cm ARPA and 3 cm ARPA radars 
Electronic chart system (ECDIS) 
Radio installation according to GMDSS area A3 Inmarsat C. Inmarsat B


Deck Machinery 
- One combined Windlass / Mooring Winch, 50 mm chain dia. 
- Two Capstans aft, pull 5,5 T


Lifesaving Equipment 
- Two enclosed lifeboats with davits, each for 70 persons 
- One FRC with one-armed davit 
- One seismic workboat with one-armed davit (Owner supplied) 
- 4 of life rafts for 25 persons
- 2 of life rafts for 20 persons


HVAC Plant 
Two compressor / chiller units, each with 100 % capacity 
Chilled water fancoil cooling system 
Dimensioned for 100 % fresh air supply 
Separate air handling units for: 
- Seismic computer room (with 100 % backup)
- Converter room
- Galley


Helicopter Deck 
Fixed deck type
Size: 23 m diameter 
Dimensioned for Super Puma and Sikorsky S61 
Approvals: DNV, UK CAA


Machinery and Propulsion System 
- Two Main Engines, each of 3970 kW - 750 rpm 
- Two Reduction Gears, with secondary PTO for shaft alternators 
- Two CP Main Propellers in Nozzles, each 3970 kW / dia. 4200 mm / speed 125 rpm


Oil Purification Plant 
- Two FO Separators (MGO), modularized
- Two LO Separators, modularized


Air Compressors 
- Two Starting air compressor units 
- One Working air compressors


Fresh Water Generators 
- Two FW generators, each w. capacity 12 tonnes per 24 hours, w. rehardening filter


Fire Fighting Systems 
Inergen system for: 
- Engine room, engine control room and workshop 
- Compressor room and converter room 
- Seismic instrument area and misc. stores rooms 
- Incinerator room 
- CO2 system for emergency generator room 
- CO2 system for galley hood 
- Foam system for helicopter deck 
- SW Sprinkler system for all work decks


Electric Power Plant (450 Volt AC - 60 Hz) 
- Two Shaft Alternators, each of 3000 kVA 
- Two Generator sets, each of 1800 kVA 
- Emergency Generator, 375 kVA 
- UPS / Clean power system 208 V / 120 V - 75 kVA


Electric Equipment 
- Main Switchboard 450 V, 220 V, and 120 V 
- Emergency Switchboard 450 V and 220 V 
- Control Consoles in brigde and engine room 
- General Electric Equipment 
- Multifunctional Automation system with integration of Alarm and Monitoring system 
Tank Sounding system