Deep Loch is a location/challenge in the main Raven series. The objective of the actual Deep Loch challenge was to swim across an icy lake (wearing a wetsuit and lifejacket, of course) to win gold. If you came last, you'd lose a life.
In series 1, Deep Loch made its debut on Day 3 of the first heat. Here, Raven would instruct the five warriors to swim across the lake to continue in the tournament. On the far shore were 4 gold rings, one each for the four fastest warriors. However, for the unlucky warrior who came last, they'd lose a life, as Sejen found out the hard way, despite a gallant effort.
Like half the locations in series 1, Deep Loch held more challenges than listed on screen; the other two challenges, in this case, were Stepping Stones and Treasure Ring.
Always played as the second challenge on Day 3 of the heats, Stepping Stones was played by one warrior at a time. They were faced with two paths, one of five stones close together and one of three stones, further apart. At the end of both paths was a giant gold hoop, which the warrior playing this game had to jump through if they got to the end of their chosen path. Jumping through the hoop would guarantee the warrior a gold treasure ring (once they'd managed to drag themselves back to dry land). If they fell off their path, not only did they have another dip in the lake, they'd lose a life.
Despite there being two paths, most warriors picked the five-stone path (probably because the closeness of the stones made it easier to traverse). Moreover, there was a between 40% and 60% chance of completing this challenge.
Introduced as the first challenge on Day 3 of the second heat, the warriors in first and second place (Lamar and, respectively) would start on opposite ends of the lake, in coracles. In the middle of two ropes was a raft with a ring on it, and it was the aim of this challenge for the warriors to hoist their coracle to the raft first and get the ring first. The loser would lose a life, whilst the winner would keep the ring and then stay on to face the next warrior.
Series 2-3, 5-10
In series 2, the basic premise of Deep Loch was kept, though the amount of rings for each warrior changed. First out would get three rings, second would get two and third would get one. However, the warrior coming last would lose a life.
The map symbol for Deep Loch was changed to a more circular loch symbol with a skull on a pole and two arms on the skull. The words "Deep Loch" were moved from the loch to around the skull pole.
For finals week in series 4, there were 10 rings up for grabs. Four rings for first place (Linma), three rings for second (Kinsa), two rings for third (Dejan) and one ring for fourth (Wilja). The unlucky warrior who came last was Sarla.
This variant of Deep Loch appeared to take place on the shores of the loch virtually on the doorstep of Nevar's castle.