stern oar, scull
艣 centers on a specific boat-related tool: a stern oar or scull used to propel or steer a boat from the rear.
艣 combines 舟 (boat) with 虜, which likely contributes the sound ロ. The character is a phono-semantic compound for a type of oar or scull.
The left side 舟 is a boat, and the right side 虜 looks like a captive or prisoner. Imagine a captive forced to row a boat with a stern oar: the boat 舟 plus the captive 虜 gives you the tool they use, a scull.
For ロ, picture a row of rowers using stern oars in unison: row -> ロ, and the boat moves with each stroke.