Originally Posted by Mcd22
If its a big enough weir than even big engines won't stop you going over.
Usually the boat would be controlled by a series of ropes from the bank. Working close to the top of a weir is dangerous enough when your tied on but its actually more dangerous to work close to the bottom of it. Its like a giant washing machine.
I agree with McD22, the only safe way of working near weirs is bank crews and ropes, even safety boats fail allowing both of you to be sucked over the boil line.