I suspect that would be more accurately said something like, "The movement used with a bo to block a low kick may have been derived from the motion used to steer a boat with a pole." Even then, I question how often the movements were actually derived from those sources, versus that being used as an example to teach people who knew a similar movement.
One of the joys of Cambridge is sitting in a pub garden next to the river and watching people strand themselves on the pole as they watch the boat continue down the river on it's own.
I think that's a key... many times, movements were likely compared to everyday activities, or maybe even encouraged to practice in their everyday activities... There are tons of stories of masters teaching students by having them do things that are unrelated to the martial arts, then only after long periods of "sweeping the temple" or "wax on/wax off" were the movements "true" use shown. They had to come from somewhere, no?
Just a note - if you train yourself before going for the 1-1 training, you're likely to develop some bad habits that need correction. If you are enjoying exploring it (except for the head shots, of course), then keep doing it by all means. Just know you're likely to develop habits that will slow down your later learning. It's something I've often accepted about my own explorations - just best to go in with eyes wide open.
Likely some of them started as such, with people either messing around in boredom or grabbing what was on hand in a moment of need. When they started actually training to use them, they likely made versions specifically designed to be weapons (different balance, made to withstand impact, etc.).
There are lots of origin and historical stories that are apocryphal. So many that it is almost certain nearly every one of us (students and instructors) believes more than one that isn't literally true. Unless one makes too much of them (in this case, perhaps, trying too hard to make it exactly like some motion used by Japanese boatmen), there's little real harm and not much to gain by trying to figure out if they are accurate or not. At worst, most of them just bug some of us.
. I hope they'll have that sort of training here in SA. I'll google around. 
In most schools, weapons training starts well into the curriculum. You may be able to find an instructor who is willing to offer some private lessons to specifically work on that weapon.I 100% understand where you're coming from; that's usually the case with practicing several martial arts systems at once too, isn't it?. I will look into some professional training for the Nunchaku. I don't want to make a fool of myself either
Add the kama and kuwa (Okinawan farming hoe) to the list of actual tools turned weapons IMO.
