Rowing does not need to stop after you have graduated. Contact the Honorary Secretary (firstname.lastname@example.org) with your non-Cambridge email address and you will be added to the mailing lists. On this you will be invited to Boat Club Dinners and other social events and will be informed of kit orders. More news can be found here.
The Cross Keys Boat Club exists to facilitate rowing for alumni. It uses PBCs equipment to participate in races and social rowing, for example, a CCKC boat participated in Fairbairns 2012. If you would like to contribute to PBC, more details are explained here.