The last time Aquabotix said the US Navy was sniffing around its drone submarines, its stock jumped 12 per cent.

This time, it appears drone-o-phile investors are still on holiday.

The company (ASX:UUV) has signed its second contract with the US Navy, a deal worth $70,000 to develop the SwarmDiver product further for the organisation.

“This development contract will provide greater flexibility in the systems’ use while maintaining the benefits of conducting an unmanned mission,” said CEO Whitney Million.

The stock dipped 2 per cent to 4.8c on Thursday.

The first US Navy deal was with the Cooperative Research and Development Agreement with the United States Naval Undersea Warfare Center, a Federal laboratory, in June last year.

SwarmDiver is a small underwater robot which are deployed in a mechanical swarm.

Each SwarmDiver, weighing just 1.7kg and 75cm long, can dive to 50m. They have a battery life of up to 2.5 hours and a range of 7km.

The robots are designed for military purposes – Aquabotix doesn’t say whether they can be deployed as mini-torpedoes but has applied to develop them with “explosive capabilities” – but can also be used in oceanography, aquaculture, research and hydrographic survey work.

The company raised eyebrows in November when it unveiled a new designed that left little to the imagination.

Aquabotix shares over the last 12 months.