This affects the pitch. Gate The bar which closes the swivel. Gearing The ratio of the oar length inboard of the pin to the oar length outboard of the pin. The section of the oar between blade and handle. The angle of the blade to the water.
Pitch prevents the blade from digging uncontrollably deep into the water.
The pitch is positive, in other words the top of the blade tilts towards the stern. Rigging The relationship between the dimensions and angles of the boat, the seat, the sculls and you. The distance from the swivel pin to the centre of the boat. The distance between the swivel pins. What ordinary folk call the 'rowlock' - it carries the scull and rotates on the pin.