The 'Under Water Tunnel' - voted the most dreaded obstacle 5 years running.  The approach to the tunnel is wading through chest deep water.  As a concession we let you drop in the water halfway round the river in the winter, but in the summer you've got to do the full 200m.  The river has a series of acclimatisation dunks as your route is blocked by telegraph poles.

The tunnel itself has been rebuilt ready for 2005, it is now 50% wider to ease bottle necks,50% longer and to add a new level of danger we've reduced the air pockets too!

Obstacle Rules

Elite : - Single dive through the tunnel - no opportunities for coming up for air!
Mere Mortals : - the classic route, 2 small dark air pockets to break up the tunnel
Old and infirm : - if its bellow -5 °C and you've got note from you mum and we might let you walk round!

Here you can see Tough Guys emerging from the Tunnel, most people if they have done the obstacle properly in one breath are quite dazed and disorientated after emerging; this is quite normal!

The Berlin Wall