Does every oar need a blade?

[ocni]

I admit to having a poor yachting image and rowing technique, I am a sailor who rows to sail but sometimes the means to an end becomes a distraction. Question is: why such a large difference in blade area has so little effect on performance, it seems impossible to row straight with such an imbalance no matter how bad my technique?

[jamesg]

why such a large difference in blade area has so little effect on performance,

Because performance depends on us. What blade shape changes is efficiency.

Modern blades shapes increase the hydrodynamic wing effects at catch and finish, where the blade is moving axially through the water, reducing turbulence and slip.

To allow for this the outboard length is shorter, reducing gearing and increasing ratings. Nowadays we may see the entire 2k done at 40.

In any case the cubic power law applies, so large speed changes cannot be expected.

[ocni]

Modern blade shapes may not be the best fit for the use and geometry of a dinghy. The 3 blades in video vary greatly in area and aspect ratio yet perform equally well. If such a large area reduction were applied to a modern blade, I assume performance would suffer? I am quite the amateur here, no idea "2K in 40", (distance-time?) but I have been rowing with a matched pair of the middle oar for 2 years in various conditions to good effect. The only obvious efficiency is in using less material for the same effect. They are easy to build, store, carry and better balanced, all good for my type of rowing. But this leaves unanswered the question of area reduction's non-effect?