Many thanks for that, Ive been talking to Marshalsea and they ve been very helpful but the max we can get is 1000 BAR. Funny you mention the Royal Navy because I used to serve onboard HM Submarines but unfortunately the hydraulic pressures were nothing like 1500 BAR, well not on the boats I served on. There is a detail that I hav'nt mentioned is that the requirement for 20 Ltr @1500 BAR is only needed for intervals of 10 sec, 5 sec and 1 sec, so in other words its not needed to be sustained for long periods. Ive thought of using intensifers and accumulators but the accumulators at that pressure dont exist.