I'm using a Tarot T-2D 2-axis brushless gimbal which is essentially designed for drones. I take the original wheelhouse off and install the whole camera system instead: brushless gimbal, 3S/2200mah LiPo, 5V BEC and dedicated receiver (although I rarely tilt the camera).
Here are details on the rig:
http://rc.noalia.fr/boats/sequana/log20150403Looks like this once completed:

There are smaller stabilization systems but it will always more or less turn your boat into a "video rig" (ie: can't expected to keep scale appearance).
But I'm happy with the whole setup. In the video above you can see how well it works at 3'47. My springer was rocking just like the other boats but camera stays level.
Alain - the Jupiter's owner and builder - has uploaded pictures over the years on the MCCR website:
http://www.mccr78.com/index.php/bateaux/photos-videosYou'll find her among pictures from other boats at various events.