Editing Dynamic positioning (section)

==Power and propulsion systems==
[[image:North Sea Giant offshore installation vessel.jpg|thumb|North Sea Giant]]
To maintain position [[azimuth thruster]]s (electric, [[L-drive]] or [[Z-drive]]) [[bow thruster]]s, stern thrusters, [[Pump-jet|water jets]], [[rudder]]s and [[propeller]]s are used. DP ships are usually at least partially [[Diesel-electric transmission|diesel-electric]], as this allows a more flexible set-up and is better able to handle the large changes in power demand, typical for DP operations. These fluctuations may be suitable for [[Hybrid electric vehicle#Marine and other aquatic|hybrid operation]]. An [[Liquefied natural gas|LNG]]-powered platform supply vessel started operation in 2016 with a 653 kWh/1600&nbsp;kW [[battery pack|battery]] acting as [[Operating reserve|spinning reserve]] during DP2, saving 15-30% fuel.<ref name="Battery" /> The 154-meter North Sea Giant has combined 3 powerpacks, switchboards and 2 MWh batteries to operate in DP3 using only one engine,<ref>{{cite web |last1=Stensvold |first1=Tore |title=Et av verdens mest avanserte skip er bygget om: Sparer 30 prosent drivstoff med batteri |url=https://www.tu.no/artikler/et-av-verdens-mest-avanserte-skip-er-bygget-om-sparer-30-prosent-drivstoff-med-batteri/432656?key=17JN041I |website=Tu.no |publisher=[[Teknisk Ukeblad]] |access-date=31 March 2019 |language=no |date=14 March 2018}}</ref><ref>{{cite web |title=The Motorship {{!}} Giant battery boost for North Sea Shipping |url=https://www.motorship.com/news101/ships-equipment/giant-battery-boost-for-north-sea-shipping |website=www.motorship.com |access-date=31 March 2019}}</ref> keeping the engine load between 60% and 80%.<ref>{{cite web |last1=Førde |first1=Thomas |title=Dette fartøyet sparer penger og kutter CO2 med avansert batterisystem |url=https://www.tu.no/artikler/dette-fartoyet-sparer-penger-og-kutter-co2-med-avansert-batterisystem/465783 |website=Tu.no |publisher=[[Teknisk Ukeblad]] |language=no |date=31 May 2019}}</ref>

The set-up depends on the DP class of the ship. A Class 1 can be relatively simple, whereas the system of a Class 3 ship is quite complex. On Class 2 and 3 ships, all computers and reference systems should be powered through a [[Uninterruptible power supply|UPS]].