Welcome to the wonderfull world of Subs :dancing1:
I am onto my 5th sub now and still a gluten for punishment I still love building and flying them.
I started off with a Robbe U47. Pretty reasonable priced kit, with good buildings and schematics. I found that it was pretty stable and handled well in the water. Plus if your really keen you can convert it to a static diver with a piston tank. I did that with mine and it works pretty well.
But what kit I suppose it depends on what you want. I dont know if you have had much experience of subs, so please dont think I am being cheeky here, but theres the Dynamic diving, where the boat has a slight positive bouyancy so the motors have to push it under with the forward hydroplanes. Acts like a porpois in the water.
Then theres the static divers. Those are like streamline boats, Darnell ( Metcalf mouldings ) boats or Engel boats. They use Piston tanks, or ballast balloons to inflate or displace water. But they are true subs and have the advantage of being able to dive on the spot without movement.
Also depends on how much you want to spend. I think my U47 was about £300 ? The Metcalf mouldings Royal Navy "T" Class was about £500 ish and my Engel Typhoon was about £1200 all in. If she ever knew she would go mental!:grinball2:
I would start with a Robbe U47, or if your feeling adventurous get any Engel kit, there (in my opinion) one of the best about.
But whichever you choose there are a few of us on here have them or building them and always here to help if we can. I have a thread on here for my typhoon which i am building. Have a look, see if the Engels interest you.
Good luck:regards:
Paul