Around 1990, one of the staples of rowing design changed, possibly for good. The traditional blades, also known as “macon” or “tulip” (A possible nod to the Dutch) blades were replaced by the first ever “big blade” which are now known as “hatchet” or “cleaver” blades. Designed by a pair of prolific inventors, the Dreissigacker brothers, these blades abandoned the symmetry of traditional blades in favor of oars that were side-specific (Port and Starboard).
The hatchet blade provides a fairly simple upgrade to the macon blade. As a result of being designed for a specific side of the boat, it provides an increase of blade surface area underneath the water, while simultaneously reducing the amount of oar shaft that enters the water. Increased blade surface area increase thrust while decreased shaft area decreases drag. Hatchet blades also just look faster. They look modern. They look efficient. Next to hatchet blades, macon blades look like that old coffee maker we all have: totally reliable and useful, but foolish looking next to a new 7,000 watt toaster oven (aka Mahé Drysdale).
Upon their invention, the initial claim was that hatchet blades are about 2-3% more efficient than traditional blades. At first, this made me do a double-take. That’s marginal improvement at best. And while this is true, such an increase in efficiency can lead to a 8-12 second decrease in time over a 7 minute 2k. This is a substantial amount; however, there have never been any hard data presented to back up this claim. FISA itself did a strange study involving a sample size of one that suggested efficiency gains may actually range around -3 to + 7%.
Nowadays, every company produces blades that have nearly identical hatchet designs. Details from blade surface area to blade cant and curvature vary only slightly between brands. As fuzzy fluid dynamics support this current “meta” design, it may be only a matter of time until a new design replaces the traditional hatchets we use today.
