The Patrol Boat Autonomy Trial (PBAT) will help develop knowledge across Industry and Navy about the ‘logistics of autonomy’ as it explores the operation of larger Uncrewed Surface Vessels (USV). The activity, sponsored by Warfare Innovation Navy (WIN) Branch, is currently in the process of converting ex-HMAS Maitland (renamed PBAT Sentinel) into a large USV before commencing a series of sea trials.
The prime industry participants in the trial are Austal, who are focused on mechanical systems, and L3Harris UK who are providing the figurative ‘brains’ or navigational control of the vessel. While the two companies are leveraging autonomy work done by Austal USA and L3Harris U.S on T-EPF-13, USNS Apalachicola, they’re doing so in an ITAR-free way to develop and retain sovereign Australian capability.
Leveraging Legacy Assets
Ashley Hamilton Rice, Head of Sales and Business Development - Defence, at Austal told ADM that the trial was important to the company because it sees repurposing existing assets for uncrewed missions as an important area of market growth.
“[Austal is] identifying and looking at the market and where there are opportunities and gaps. There are basically two lines to take; repurposing existing capability, like an Armidale, to provide new capability for Defence customers and creating new uncrewed platforms.”
Converting legacy assets into functional USVs comes with a whole set of challenges, mainly focused on maintenance-intensive mechanical systems. These, Hamilton Rice said, were the ‘Achilles heel’ of developing autonomous capabilities aboard older systems and PBAT would help identify and remedy some of these problems.
“The challenge when you use existing systems, legacy systems, is trying to deal with mechanical systems that were never designed for autonomy. These mechanical systems will normally require crew intervention. [Part of PBAT is] going through the [trial] process to understand where those vulnerabilities are”
Commodore Darron Kavanagh, Director-General of WIN Branch, said that his focus was also on learning about the reliability of mechanical systems aboard USVs so that the RAN can gain a better understanding of requirements as it looks to procure more uncrewed systems in the future.
“Our main goal is to learn more about the logistics of autonomy which we can apply to future RAN platforms. That is, on a crewed vessel, we might only need one oil filter, how many will we need on a USV? Do we need double redundancy? Those are the sort of issues we’re exploring [through the trial]”
CDRE Kavanagh explained to ADM that WIN Branch and its industry partners will be taking a ‘crawl, walk, run’ approach to conducting sea trials of the uncrewed vessel.
“We’re taking a crawl, walk, run approach to PBAT. The first step will be remote control of the vehicle, then we’ll experiment with autonomous navigation between waypoints. Finally, we will conduct a long-duration endurance test off the coast and away from major shipping lanes.”
Hamilton Rice said that, from Austal’s perspective, the most challenging part of the trial wasn’t offshore operations, but learning how to operate autonomously within busy waterways such as ports.
“When you’re in cruise it’s ok but when you come into the difficult task of manoeuvring and docking a vessel, that’s where the challenge is.”
The Flip Side of Continuous Shipbuilding
The entire PBAT activity is expected to take place over just 18 months, after which Sentinel will be disposed of. Asked if other decommissioned Armidale class patrol boats could be converted after Sentinel, CDRE Kavanagh said the ships to do so are ‘certainly there’ and that future, iterative conversions were a ‘possibility.’
CDRE Kavanagh also flagged how PBAT shows another benefit of a continuous shipbuilding program which isn’t often considered; a near-constant supply of surplus vessels for experimentation and research.
“PBAT’s [use of ex-HMAS Maitland] shows the benefit of a continuous shipbuilding program on the back end. We normally just focus on new ships but with a continuous program, we have these platforms available for experimentation to support Navy [as they leave service].”