INGENIEUR
for the umbilical winch and a-frame / LARS . The green line shows the control from the control container to the umbilical winch and the trencher .
This article focuses on the overall system and construction of the vehicle only as it is the key for the whole trenching system . Every element will be explained in very simple terms but not ignoring their technical importance to provide substantial knowledge to all readers from various background .
VEHICLE SYSTEM
The trenching vehicle comprises several subsystems that are integrated to form a fully functional subsea working trencher . In normal circumstances , a trenching ROV must be able to function like a ROV but most of the time must work as a subsea trencher . In order to do that , few important aspects have to be carefully considered in designing the trencher such as :
1 . Sufficient water pump power to perform the seabed trenching in a smooth and efficient way .
2 . The subsea hydraulic power unit must be able to supply enough power for the trencher to operate the water pump , hydraulic systems such as thrusters , hydraulic pump , hydraulic motor , and manipulators .
3 . The thrusters must be able to push the trencher forward during the trenching operation . It has to be able to hold the trenching ROV in a horizontal position during the cable / pipe burial due to the high reaction force from the water that is jetted out from the jetting sword .
4 . The structural system must be designed in such a way that all sub-systems can be easily accessed especially during maintenance . It has to be able to handle the safe working load by considering the seastate condition base on the Douglas Scale from World Meteorological Organization Sea State Code .
5 . The electrical system is designed to control the subsea vehicle from a control van or container . It can be either fully hard wired or through fibre optical integration .
A summary of the overall sub-systems for the vehicle is shown in Figure 3 .
Part 2 of this article will be published in Vol 92 .
REFERENCE
[ 1 ] IMCAR004 Code Of Practice For The Safe & Efficient Operations Of ROV July 2009 , International Marine Contractors Association .
[ 2 ] IMCAR006 Standard ROV Audit Document , February 2001 , International Marine Contractors Association .
[ 3 ] Chris Bell ( Jan 2000 ), Handbook for ROV Pilot Technicians ( 2 nd Ed ), Oilfield Publications Ltd
[ 4 ] https :// en . wikipedia . org / wiki / Submarine _ communications _ cable #:~: text = The % 20 first % 20submarine % 20communications % 20 cables % 20laid % 20beginning % 20 in , cable % 20which % 20became % 20 operational % 20on % 2016 % 20August % 2- 01858 .
[ 5 ] Tate , K . W .; Tudor , W .; Eaton , R . Protecting Submarine Cables from Accidental Damage . In Proceedings of the Offshore Technology Conference , Houston , TX , USA , 3 May 1982 .
[ 6 ] Pierre Guy Atangana Njock , Qian Zheng , Ning Zhang and Ye-Shuang Xu . Perspective Review on Subsea Jet Trenching Technology and Modeling . Journal of Marine Science and Engineering , 22 June 2020 .
[ 7 ] BERR . Review of Cabling Techniques and Environmental Effects Applicable to the Offshore Wind Farm Industry : Technical Report ; Department for Business Enterprise & Regulatory Reform : London , UK , 2008 ; p . 159 .
[ 8 ] Brunning , P .; Machin , J . Applications and performance of trenching technologies in Asia-Pacific . In Proceedings of the Annual Offshore Technology Conference-ASIA , Kuala Lumpur , Malaysia , 25 – 28 March 2014 ; pp . 1447 – 1462 .
[ 9 ] Warringa , S .; Rhee , V . C .; Miedema , S . A .; Lupea , C .; Visser , C . Modellling the waterjet cable trenching process on sand dunes . In Proceedings of the 22nd World Dredging Conference , Shanghai , China , 22 – 26 April 2019 ; pp . 1135 – 1152 .
70 VOL 91 JULY-SEPTEMBER 2022