I have long wondered why rowers row in sync. That causes a burst of speed and power when they all drive and then a lull in speed when they all recover. That burst of speed raises the force of resistance from the water to the cube power.

Rather, why not split the rowers into 2 groups? Have drive while half recover. And vice versa. The speed curve of the boat won't be so peaky. And the cube law resistance from the water will be much lower.

Seems like that would more efficiently turn total power into average speed, and waste less power on overcoming water resistance?

I understand there may be physical issues with long oars not cycling in sync. But perhaps there's a boat design that could solve this?