  We present the blind Westerbork Coma Survey probing the HI content of the
Coma galaxy cluster with the Westerbork Synthesis Radio Telescope. The survey
covers the inner $\sim$ 1 Mpc around the cluster centre, extending out to 1.5
Mpc towards the south-western NGC 4839 group. The survey probes the atomic gas
in the entire Coma volume down to a sensitivity of $\sim$ 10$^{19}$ cm$^{-2}$
and 10$^8$ M$_{\odot}$. Combining automated source finding with source
extraction at optical redshifts and visual verification, we obtained 40 HI
detections of which 24 are new. Over half of the sample displays perturbed HI
morphologies indicative of an ongoing interaction with the cluster environment.
With the use of ancillary UV and mid-IR, data we measured their stellar masses
and star formation rates and compared the HI properties to a set of field
galaxies spanning a similar stellar mass and star formation rate range. We find
that $\sim$ 75 % of HI-selected Coma galaxies have simultaneously enhanced star
formation rates (by $\sim$ 0.2 dex) and are HI deficient (by $\sim$ 0.5 dex)
compared to field galaxies of the same stellar mass. According to our toy
model, the simultaneous HI deficiency and enhanced star formation activity can
be attributed to either HI stripping of already highly star forming galaxies on
a very short timescale, while their H$_2$ content remains largely unaffected,
or to HI stripping coupled to a temporary boost of the HI-to-H$_2$ conversion,
causing a brief starburst phase triggered by ram pressure before eventually
quenching the galaxy.
