Hello all,
Even the great HO scale modeler John Allen abandoned the notion of actual water on his pike for the same reasons mentioned.
His solution was to use a rippled or textured glass on his mill pond to replicate the look of water.
I would suggest adapting a similar solution.
The glass could be placed over a painted underwater scene-scape. Through the use of color grading depth could be replicated while maintaining a parallel surface under the glass.
Then a track or path could be cut in the underlying scene-scape. A motor could be placed in the center of the area.
A horizontal arm would be extended from the motor, with a possible support on the outer edge of the area.
Attached to the horizontal arm would be a vertical element with a magnet that would move just under the glass "water." This element would not be fixed to the horizontal arm, but allowed to move along it's length and track through the track or path cut in the sub-scenery.
Then a water craft, with an alternate polarity magnet, could be placed atop the glass "water."
When the motor is actuated the circular motion of the arm tracking through the path of the track cut in the sub-scenery would move the craft. The texture of the glass could also provide the bob of the craft across the surface. If the surface of the glass is smooth, not textured, then there would be no bob of the craft.
If you place the connecting magnets of the craft on the bow, when the polarity of the motor is reversed, then the craft would come-about.
All this without having to introduce actual water into your pike.
Hope this helps.
