The limited space in a raft makes careful planning essential. A camera with a pop-up flash will work fine to fill in shadows. Take an emanhattan long telephoto and tripod only if you plan to shoot from shore. Metal ammo boxes are best for keeping your equipment dry and safe. Outfitters usually provide these boxes.
Dark boxes become ovens when exposed to the sun.
In addition to ammo boxes, airtight plastic bags are ideal for sealing out moisture and grit. Sit in the back of the raft to capture both raft and river with a wide-angle lens. Or brace yourself in front for a shot backward at your fellow rafters. Use a fill flash to brighten the shade under broad-brimmed hats so you can record the expressions on your companions' faces. Although photos taken from the raft can get you close to the action, some of the prime shooting locations are found safe onshore.