The Robbe Seawolf kit IS a dynamic diver - in case you haven't seen one you just ballast the sub well down in the water until the decks are awash - then after setting the front dive planes slightly down (with a mechanical adjustment) just move the sub forward slowly to stay on the surface then speed up and down she goes. There is an option to have the rear planes fixed, but I would recommend having a servo to operate them - it makes the dive and recovery much easier. By the way when you slow the boat down while travelling under water she just pops up again anyway. Hope this is of some help.

Ian