Kontiki season is picking up here in Southern Africa, with Windhoek, Namibia hosting their event this weekend, and the Western Cape hosting theirs next weekend.
The diagram above shows one way of fastening barrels that worked well for my troop. You can double up with a second rope starting at the opposite corners to make it really secure. Apart from the ropes, the spacing of your poles is really important to make sure that the barrel sits securely on the raft base.
drawn on iPad Mini using Paper app and Just-Mobile AluPen