While rowing, “catching a crab” means to put one’s oar in the water at the wrong time or at the wrong angle into the water. This results in the oar flipping parallel to the boat. When an oar goes from perpendicular (good) to parallel (bad) a rower must pull the oar in and over their head.
Crabs are common among novice rowers and also seen in experienced rowers. A crab can be avoided when a rower starts to think about the following:
- Verify the pitch of the blade
Sometimes you may catch a crab for absolutely no fault of yours. If the rigging is done in such a way that the blade cuts into the water at a steep angle then there a high chance of going too deep and catching a crab. Make sure that blade is at the correct pitch as often as time permits. If the boat has had a shock its high time to check the pitch of the blade. For instance, the oar lock pitch should be around 5 degrees.
- Square the blade before the catch
Rowers feather the blade during the recovery phase of the rowing stroke (when the blade is not in the water) and square it before dropping it into the water. If a blade goes into the water while still feathered there is a high chance of catching a crab. Therefore, it is very important for a rower to start squaring the blade as he/she cross the knees gradually squaring it completely, and moving slightly on the square to take the catch as part of the recovery. There is often a small click when the blade is on the square.
- Visualize the boat on the recovery
Imagine yourself observing your own rowing from outside the boat. Visualize how you move forward at the speed of the boat and square the blade without increasing the speed on the slide. The pause on half-slide drill is very beneficial to ensuring adequate time to square the blade.
- Time the catch
Catch is part of the recovery. It is very important to drop the square blade into the water and be ready to push immediately. If the blade enters on the feather then the rest of the team may apply force and cause the rower to catch a crab due to the speed of the boat.
A good catch can be seen a force curve when the blade is loaded immediately after it enters the water.
- Extract the blade on the square
One can catch a crab also at the finish. Make sure the blade has full pressure (body hanging at the finish) and comes out on the square due to a small tap leaving. The pressure at the finish is very important to prevent the blade from turning in the water or washing out hence increasing the chances of catching a crab. A drill that alternates between feathered-blade rowing and square-blade rowing can help the rower obtain cleaner finishes.
The force curve obtained from Oarzpot can tell a rower if there were negative forces at the finish due to an unclean extraction: