Pictured during sea trails, is an aerial view of HMS Queen Elizabeth, HMS Sutherland and HMS Iron Duke as well as a Fleet Air Arm Merlin helicopter. HMS Queen Elizabeth left Rosyth, where she has been under construction since 2014, to conduct sea trials. Type 23 frigates Sutherland and Iron Duke joined the 65,000-tonne aircraft carrier, along with Merlin Mk2 helicopters of the Fleet Air Arm, to guard the seas as the trials get under way. The Queen Elizabeth Class Carriers are the biggest warships ever built for the Royal Navy - four acres of sovereign territory, deployable across the globe to serve the United Kingdom on operations for 50 years. HMS Queen Elizabeth and HMS Prince of Wales will be the most advanced warships in the Royal Navy fleet. They are the future flagships of the nation. Initially the ships will carry helicopters. The vast flight deck and hangar can accommodate any helicopter in Britain’s military inventory. From 2020, however, our punch will be delivered by the F35 Lightning II, the world’s most advanced stealth fighter-bomber.

[box with_bg=”true” inner_padding=”small”]


  • Warship in Harbour Assessment
[/checklist] [/box] [spacer size=’small’] [box with_bg=”true” inner_padding=”small”]


  • Explosive Safety Management at Platform Level for Queen Elizabeth Class
  • Ship/Class Explosive Safety Cases/Reports for Queen Elizabeth Class
  • Safety Management Plans and Certification Strategies under JSP 430/ DSA02-DMR
  • Naval Environment Assessment Statements (NEAS)
  • Ship Explosives Store Safety Instructions (SEXSSIs)
[/checklist] [/box]
[two_third last]


System Design Evaluation Ltd (SDE) were tasked to provide support to the Aircraft Carrier Alliance to produce a Warship In Harbour (WIH) Assessment for the Queen Elizabeth Class Carrier, in support of the vessel’s Ship Explosives Safety Case.

[spacer size=’medium’]


The UK MOD’s Harbour Protection Strategy requires that Naval Base Duty Holders manage the risks from explosives posed to third parties by an ammunitioned WIH. The level of risk posed by an ammunitioned warship alongside is defined in the WIH Methodology Suite Overview as a function of the potential magnitude of an on board event, the likelihood of that event occurring and the scale of the consequences if that event does occur. The present assessment covered the first two of these key elements:

  • Effective Net Explosive Quantity (ENEQ) – The munition ENEQ, as published in the munition Ship Explosives Store Safety Instruction (SEXSSI) are used.
  • Likelihood of that ENEQ detonating together in a practically instantaneous event – A range of external threats with potential WIH implications have been collated together to form a worst case / most likely harbour environment, termed the Generic Harbour Environment (GHE). In each case the probability of that initiating event occurring is presented.

OME Safety is a core capability and the team maintain currency and competency with relevant policies, including JSPs 520, 375 and 862, DSA02-DMR along with POSMS, POEMS and Def Stan 00-56.

[spacer size=’medium’]


The output of the WIH assessment is a Warship Hazard Footprint Statement (WHFS), which can be used as direct inputs to the Naval Base Duty Holder’s consequence models.

[spacer size=’medium’]

To view a PDF version of this case study please click here.