Supply Chain Notice: WAT0149-01 B Lock Penstock Replacements- Portsmouth Naval Base

The Tenderer should be aware that the works detailed in this package are constrained due to the nature of the location they are to be conducted in.

Project location- HM Naval Base Portsmouth

The Contractor shall be expected to adhere by the HMNB site security requirements, all Contractors and Sub-Contractors shall be BPSS security vetted and will be required to hold the relevant site security passes. The Contractor shall be expected to hold the following levels of insurance £10m Public Liability, £10m Product Liability, £5m Professional Indemnity.

KBS Maritime - Introduction

KBS Maritime is a joint venture between KBR and BAE Systems, bringing together two global players with a rich heritage of delivering excellence, innovation and reliability. The joint venture will combine the expertise of KBR as a global leader in infrastructure asset management and services with BAE Systems' experience and capability within Portsmouth Naval Base. KBS Maritime are delivering an ambitious, modern and enduring change to the Portsmouth Naval base infrastructure, securing investment in the local community and ensuring fit-for-purpose, world-leading fleet support for the Royal Navy and the UK in the decades ahead.

Project Background

KBS Maritime has a requirement for penstock replacements at B Lock within Portsmouth Naval Base. The project consists of 10 in number replacement penstocks in 6 chambers overall. The penstock system controls sea water via a culvert system between the harbour, the basin and the dry docks. These include levelling penstocks of circa 8 metres deep to drainage penstocks circa 18 metres deep. The replacement programme will replace the current cast irons doors with new with specification to be agreed along with the associated shafts, wedges, door nut, brackets, platforms, ladders and actuation and road plates. This project is due to commence in Q4 2026 with all to be replaced by Feb 2030.

Contractors must be able to demonstrate design, manufacture and installation of penstock replacements in a marine environment including all site management under CDM regulations and competency of Health and Safety compliance and safe practices. Contractors must also possess at least five years' experience working within a marine environment. Contractors who do not provide suitable and sufficient evidence of this will not be considered.

Key Dates (approximate)

- Expressions of Interest close: 18/06/2026 - Bidders Selected: by end of June 2026 - ITT Published: early July 2026 - ITT Close: early September 2026 - Project commencement: December 2026 - Project Completion Feb 2030