Pat,
Thanks.
I would have guessed around 40kg.
So not too far off.

We used to put two on 12 ft cats until they became very confident and then they could sail by themselves if they wanted.
Same experience this end.
They always had a great time playing dodge ball and they got to learn boat handling skills trying to manouvre their boats in the game.
I think I enjoyed watching them as much as they enjoyed the game.

I know that the voices in my head aint real,
but they have some pretty good ideas.
There is no such thing as a quick fix and I've never had free lunch!