catherine and i argue again

so just now i was talking to my crazy sister, and she tells me that last night she had a dream that the whole of sydney harbour froze, and people could go iceskating on the harbour, and she and her friends got a boat and put a blade-thingie on the bottom of the boat and went 'ice-sailing'
..
well obviously that was the most retarded thing i have ever heard in my life, because well, who ever heard of ice-sailing, i mean come on, shut up
because obviously when she said to me 'and me and my friends put a blade on the bottom of a boat and went ice-sailing', i invisioned this retarded looking boat with one giant blade in the middle on the bottom, and well of course everyone knows that would be retarded because if the boat stopped moving for like one second, then it would tip over to the side
so when i told my dear sister this, she replied that yes, maybe the boat would tip over, but its not as if it would completely turn upside down because it would get stopped by the ice
..as if there is nothing wrong with what she just said
so then i said, i said catherine, i said, so what if the boat tips over to the side, how the hell is it supposed to get moving again? and she said, well the wind would push it of course
and im like
what the hell
you would have to like, prop the boat up with a stick on one side, and also make sure it didnt fall over to the other side, and wait until there was a strong enough gust of wind to make it start moving again, and the odds of that actually happening, or it happening and then actually working, are like a dillion to one
anyway, then she proceeded to explain that when she said the boat had a blade on the bottom of it, she actually meant that it had two blades on the bottom so that the boat could balance on the ice
and the following argument ensued:
me: well if thats what you meant, why didnt you just say that there were two blades?
catherine: i thought that you would just assume
me: why would i assume, if you said 'there is a blade on the bottom of the boat'. a blade. one. singular
catherine: yeah, but its like iceskating. you dont have one blade, you have two blades
me: thats because you have two feet
catherine: yeah but you dont iceskate on one foot
me: some people do
catherine: no they dont!
me: yes they do!
catherine: no they dont!
me: anyway even if you have two feet, you still only have one blade on each foot
catherine: so what?
me: so, the boot is like the boat. and you only have one blade on each boot, so you should only have one blade on each boat. unless you have two boats, there is no way you could have two blades, so you would only ever need one blade because its not as if people sail with one foot on each boat, they just have one boat. if they had two boots, they would have two blades. and the boot is like the boat. so if you had two boats, you would have two blades. but you dont. you only have one boat. so you only have one blade
catherine: (pause) yeah, but people dont iceskate on one foot
me: ARGHHH

anyway i feel like my point came off fairly well, and once again, catherine lost