Used to be a regular start tactic ( lightish weather )in the Tornado fleet at Worlds and Euros - don't ever recall any protests resulting from it.
It was a regular one up to the Prep signal (i.e. 5 mins in a 10 min cycle) in fleets I've sailed in (not Tornado). But after that
Except when permitted under rule 42.3, any single action of the body that propels the boat (in any direction) with the effect of one stroke of a paddle is prohibited.
Applies and so it's a nono.