Project overview

Torpedo SEAL is a small electric swimmer Delivery Vehicle for two divers. REAPsystems designed the advanced Lithium Polymer battery and charging system. Either one or two battery modules can be installed in order to optimise either for weight or for range. The vehicle uses two thrusters, delivering a range of up to 10NM at a maximum speed of 4kts, to the typical operating depth of up to 12m and payload of 120kg. Its special design enables trouble-free transportation, storage and deployment. It can be airdropped, simply stowed and stored in a standard 533 mm torpedo tube on submarines. With its outstanding features, Torpedo SEAL has considerable implications in terms of underwater survey, submarine reconnaissance, counter-narcotics and harbour patrol, mine countermeasure operations and delivery of explosive ordnance.

As featured in Michael Bay's The Last Ship


Our solution

On this project, we worked very closely with our customer in order to deliver a custom turnkey battery and charging solution within tight timescales and budgets.

Using our more than ten years of expertise in designing and managing large lithium-ion batteries as well as many lessons learnt from more than 120 projects world wide with our BMS systems, we supported our customer identifying key requirements and specifications for a battery and charging system. 

We supplied a rapid prototype battery and charger within weeks. So, the customer was able to test their systems and refine their requirements and specifications. Following this we designed and supplied a first prototype (A-Sample) that could be used under water. 
The rapid initial prototypes allowed the customer to gather very valuable experience in a real world scenario.

The requirements and specifications were finalised, we designed the battery and charger in its final form and function, developed all production processes, QM and final quality control tests. Then started supplying a number of batteries and chargers that are now already in operation. Validation tests are performed by REAPsystems too. We ensure that our designs and production processes are capable of meeting the requirements.

Key challenges

The timescales of this project together with the very innovative nature of the system have proven to be the biggest challenge. We had to find the most suitable approach that would allow the customer to use a battery and a charger very early in the project. So, they could test the rest of the vehicle whilst our design of the battery and charger was carried out. We strive to offer short lead times, which is a proven challenge in an industry (underwater technologies) where most of our suppliers only offer very long lead times.

Also, the design for low weight and size was very challenging. The battery had to fulfil very stringent requirements in terms of weight and space envelope. At the same time, we had to ensure that the battery can safely be operated down at depth in sea water.


"We all think you have done a splendid job. Even though we seem to always try to push what is possible in terms of time and cost you not only deliver first class quality in time, you also approach this and our other projects in a way that has helped us with more than just batteries, and we are very thankful for that. Your sense of responsibility and patience is admirable."
Tobias Westling, Head of Electronics