Friends..and Colleagues i am planing to make a submarine that must dive in ti 1.5 meter...is it possible to make a craft like that..?  will someone advice...?

If anyone is capable of making a rc submarine, it is non other than you. Start a build as soon as possible.

Maharana..i am in a confusion now, that will a craft with 3 meter length with stand the pressure of 1.5 meters..? possible..? if so what kind of material can be used..? please...?

Yes it is possible, if we obey the nature's law, underwater pressure & buoyancy.

I read somewhere that PVC, fiberglass, Lexan-plastic etc are used for making submarines.

Here is a link with details on diving mechanisms for submarines:
http://www.rc-sub.com/resources/index.php5

Hope you find it useful!

Oh my God...thank you, my Friend...for the link and advice...

My pleasure, sir!
It would be really nice to see a build-log of your submarine.

swapnil..now i got the idea..and by this night i will start my work..thanks for the idea to me...god may bless us...have a nice time...

hi mate.
good luck with you're design.
the radio would need to be a mhz so the antena is long and standing up from the hull.
1.5mts deep would be very poor signal.
regards
don

Sunk Sir, i have completed the whole mechanism of the SUB, and it working nicely. it spans over 3.8 meters and 20 inch in Dia...each and every controls are based on electronic switching, all driven by toy RC means by RX and TX 2B s...now i am facing a great problem about the radio..because of the  toy rc, frequency clashing is happening. so, i talked to the related officer of my project, to give me a professional radio. he is convinced. but i tried it with a 2.4 Ghz radio, from my Colleague,but it is not responding under water almost..so will you suggest me a good working frequency that works under water nicely..please its a humble request, because i am losing my sleep because of this problem.then only i can start the final finishing works of it...please...advice me once ... 

hi mate.
2.4 gig is not rcomended for boats as it gets reflected from the water. you need mhz radio  this will penetrate the water better but will need an aerial that stands upp from the hull ....like a snorkle . as I said earlier 1.5 mts is extremely deep for radio signals.
regards
don

Thank you Sir...i will try with Mhz radio..and also try a transponder placed under the water to avoid long antenna..so have to start the work on them..thank you Sir..

hi mate.
transponder........ not thought of that but yes that would be good then you can experiment with depth for signal range.
I have just found this. very good site for what you are doing.
http://associationofmodelsubmariners.com/radio-control-underwater.php
regards
don

Sunk Sir...a million thanks for the link......thanks once again...

This is going to be an interesting build. I hope to see a build log too.

Good morning and sure...and i started my work with it...of two..one in to 2.7 meters, and one 3.2 meters.first one is equipped with conventional piston tank concept, while second one is based on my own design, with a huge ballast tank made out of brass, and compressed by a air tank took from a kerosene stove with a hand pump. i replaced the hand pump with a 12 volt car tire inflating pump, and experimenting. she is working well and nicely. but from last day my back pain is increased so now in a rest,....so friends i will post all making steps here and i hope it may help you all some...have a nice day...

hi mate.
Glad you were able to start.they sound good so far . a pic of the systems would be nice
regards
don

sure Sir...i will post a detailed article about my build...but by last day i am suffering from the back pain again...but soon i will be back...thank you..