Funny Ha Ha; Funny Peculiar

As we rowed up to the St Denys club on Saturday, we were passed by a coxless pair. I've never done it, but rowing a pair boat is horribly difficult I believe, just asking for frequent duckings. The power on either side has to be exactly balanced if you are to stay upright. And rowing a coxless pair is perfectly insane - you bump into things all the time as well as getting the duckings.
Among the lovely vintage rowing boats at the St Denys club are several coxed pair clinker boats, which look precarious enough though the risk is much lower than with a modern flying toothpick.
We wanted to try one, but it had been put in the water for the first time since last summer and was filling rapidly so we didn't.
I have this vague memory of my mother telling me that a  pair-oared boat was known as a 'funny'. Does anybody know definitively what a rowing funny is?
It's no use googling 'funny rowing boat'. You just get stuff like this: