I've started building my first R/C boat, from an old plan of Indias hobby centre, for that I need Propellor
shaft, and stern tube assy (12")  etc:. Can anybody help me in getting the above things

Tobin

please go through this topic:
http://www.rcindia.org/wanted/prop-for-speed-boat/msg112603/#msg112603

Normally all the prop. are made for 4mm shaft and 6mm stuffing tube which you can arrange locally. you have to arrange 4mm drive dog somewhere.
http://www.hobbyking.com/hobbyking/store/__12713__4mm_Drive_dog.html

Depending on the size and weight of the boat that you are building, you can use a variety of readily available items for your Propeller Shaft and Stuffing Tube. Thick Bicycle spokes are good substitute for brass propeller shafts, but they do tend to rust over time unless you lubricate them. 2mm Brass Welding rods can also be used. Copper pipes are available at shops that sell refrigeration and air conditioner spare parts. You can use that for the stuffing tube.

If you follow the many threads of the accomplished boat builder Mr. Roopesh Krishna, you will see that he uses different materials for prop shafts and tubes. You may also contact Alokehovercraft on this forum. I have bought many such items from him at very reasonable prices.

By the way, which boat are you planning to build?

Thank you Maharana and VC for your kind informations. I used to build boat models out of plywood in my teens, Now at the age of 40's I got an old torn and  rugged plan in A3 size paper belong to India's hobby centre. It has no name ,but it's a 36"cabin cruiser

Tobin