Loch Striven is a sea loch adjoining the west side of the Firth of Clyde just north of the Isle of Bute, where it forms a narrow inlet about eight miles long extending north into Argyllshire's Cowal peninsula. During times of recession in shipping, the loch has been used as a sheltered anchorage for laid-up vessels such as large oil tankers.The Danish shipping company Maersk used the loch for cold layup of some of its vessels namely the b- class vessels in its fleet.
The upper reaches of the loch, because of their secluded location, and their topographical similarity to Norwegian fiords, were used extensively for midget submarine (X-craft) training during World War II. The training programme was directed from HMS Varbel in Port Bannatyne to the south in the luxury Kyles Hydro Hotel, overlooking the Port, which was requisitioned by the Admiralty to serve as the HQ for midget submarine (x-craft) operations, including the top secret and audacious attack on the Tirpitz. Ardtaraig House, located at the head of Loch Striven, and similarly requisitioned by the Admiralty, became a secondary naval base for the 12th Submarine Flotilla midget submarines and became known as HMS 'Varbel II'.
- "Ships moored on loch during slump". BBC News. 30 June 2009. http://news.bbc.co.uk/1/hi/scotland/glasgow_and_west/8127423.stm. Retrieved 20 October 2013.
- Bute at War
- Location map: 55°56’30"N, 5°4’56"W