How to NANDroid a phone without ClockWorkMod? I'm almost sure that there is no ClockWorkMod Recovery for my phone (I've been reading some questions and answer in the forum and also google it with this result. So when I installed ROM Manager the first thing I was asked to do was selecting my phone model which wasn't in the offered list.
I want to do a NANDroid but I'm not sure how. In the question I read here I saw Odin, Amon-Ra and Heimdal. I really have no idea what this three tools / apps are and how to use them. What is each one of them? How can I make a NANDroid?
If it helps I have a Samsung Galaxy I551
Thanks!
First, some disambiguation is in order.

Amon_Ra is a developer who created one of the recovery consoles (named after himself.)  Just like ClockworkMod (which was created by a different developer named Koushik Dutta, a.k.a. Koush) Amon_Ra's Recovery performs various low-level tasks on Android devices.

Odin is a Windows application that can be used to flash firmware onto various Samsung Android handsets and tablets.

Heimdal is a cross-platform application (available for Windows, Linux and OS X) that uses the same protocol as Odin to interface with Samsung devices in "download" mode.

NANDroid is a script which runs in Android Recovery mode and dumps the image of the devices' partitions onto the external media such as SD Card.  It requires root and some other libraries to function properly.  For restoring, the recoveries use a different script which utilizes the fastboot binary to flash the image files created by NANDroid back onto their appropriate partitions.

With the above said, neither Odin or Heimdal can be used to take backups of devices; they are purely for flashing firmware onto them.  ClockworkMod or Amon_Ra Recoveries do include the NANDroid script.  However, due to the differences in partition layout, they need to be modified specifically for a given device they are ported to.  If you are knowledgeable enough, you can try to adopt the NANDroid script for use with Samsung Galaxy i551, and run it manually via ADB shell while the phone is in Recovery mode.  Again, you will need root privileges and other libraries compiled specifically for this device.