Well, dd_rhelp is a bash script that uses dd_rescue in order to try to rescue data from hard drive with bad blocks. I've already used it for my computer, but the hard drive wasn't such in a bad situation: I had rescued everything.
In this case, the hard drive belongs to a dedicated server on hire, and unfortunatly, I had no way to do a backup. Moreover, the hosting service, which is supposed to furnish a perfectly working hardware, only changed the hard drive five days after the disk began to have bad blocks!
If you want to learn more about dd_rescue and dd_rhelp, you can look at http://www.garloff.de/kurt/linux/ddrescue
There is also another ddrescue (not dd_rescue) which does a similar work as dd_rhelp: http://www.gnu.org/software/ddrescue/ddrescue.html