need to use common sense when climbing the float tube, therefore, a good idea would be to tie the float tube. also, pay attention to the maximum weight capacity of the float tube. this information will be very easy to find as this piece of information is usually mentioned on the float tube itself, on the packaging as well in the instructions booklet.
float tubes were specifically designed for still waters such as a lake and in some cases, slow rivers. however, if you plan on fishing in larger lakes or fast-moving river then you are going to need to buy either the biggest float tube or better purchase a pontoon 