# The Ocean-Going Autonomous Ship--Challenges and Threats
## 4 The Case of the First Unmanned Ship Crossing the English Channel
### SEA-KIT--Built, Trials, Unmanned Operations  
SEA-KIT has been designed by the UK Company Hushraft Ltd., and built as the part of the GEBCO-Nippon Foundation Alumni Team solution for the Shell Ocean Discovery XPRIZE Challenge [6; 7; 8]. The requirements of the competition determined the size and functionalities of the vessel. The hull with a detachable mast fits inside the standard 40-feet shipping container, which allows it to be mobilized in any part of the world relatively quickly and cost-effectively. The specification of the vessel is presented in Table 5.  
The unusual shape of the hull ensures good stability, necessary for the survey work and the optimal use of space inside the vessel in the situation where the midship part is reserved for the transportation of Autonomous Underwater Vehicle, launched and recovered through the stern part.  
\begin{table}
\begin{tabular}{c c} \hline \hline
**Feature** & **Description** \\ \hline \multirow{4}{*}{Dimensions:} & Length: 11.75 m (38.55 ft) \\  & Beam: 2.2 m (7.22 ft) \\  & Transport height: 2.0 m (6.56 ft)–Operational height: 8.5 m (27.89 ft) \\  & Weight: 12,000 kg (estimated) \\ \hline \multirow{4}{*}{Fully redundant propulsion and communication systems} & Propulsion: 2 \(\times\) 10 kW/1200 rpm electric directional thrust motors \\  & Communication: Wi-Fi, Radio, Satellite (VSAT, Iridium, Immarsat) \\  & and Kongsberg Maritime Broadband Radio (\(<\) 45 km offshore) \\  & Closed-Circuit TeleVision: 2 interior and 6 fore and aft cameras, \\  & 360 degree FLIR camera \\ \hline \multirow{4}{*}{Three independent power supplies} & Generator 2 \(\times\) 18 kW 48 V DC \\  & Fuel 2000 L \\  & Dual-purpose batteries for the engine and propulsion \\ \hline \multirow{4}{*}{Payload} & EM 304 Multibeam Echosounder-pre-release version \\  & HiPAP 502 High-precision acoustic positioning system \\ \cline{1-1}  & Kongsberg Seates MGC-R3-SB50 motion sensor and gyro compass \\ \cline{1-1}  & sound velocity probe \\ \hline \hline \end{tabular}
\end{table}
Table 5: Specifications of unmanned surface vessel (USV) SEA-KIT ’Maxlimer’ [6; 7; 8].  
The first trials of the new design vessel have been conducted in the United Kingdom. Initially the vessel has been registered as a manned boat, first, due to the lack of regulations related to the unmanned vessel registration, second, to ensure the safety of people working on the boat at the early stages of trials. Since 2017, unmanned vessels can be registered in UK [48] and the status of SEA-KIT has been changed.  
Trials of the K-Mate Autonomy Controller and the systems responsible for the cooperation between the surface vessel und the AUV have been conducted on the waters of Oslo Fiord in Norway, mostly on the sheltered area off the Kongsberg Maritime facility in Horten.  
The vessel has been exposed to the open sea environment during field tests in Greece, working on the Ionian Sea. The final trial of the Shell Ocean Discovery XPRIZE covered 32 h on continuous unmanned, over horizon operation, including launch and recovery of the AUV and 24 h of hydrographic data collection by two cooperating vehicles. The state-of-art seabed mapping operation was easier from the navigator's point of view because there was no traffic inside the survey area during the challenge.  
The next stage was to test the technology in real traffic conditions. This kind of test was conducted in May 2019 on the English Channel, the busiest world shipping route (around 400 ships every day, according to [49]) when 'USV Maxlimer', (Figure 4a), successfully crossed the channel from Tollesbury in the UK to Ostend in Belgium.