One of the more foolish ideas I have come across lately is the notion that having all the land above water on one side of the planet could result in instability of the planet.
The problem with that idea is that it ignores the size and mass of this planet. I've done some calculations below, and a 30 km average depth of ocean - average, not in a few places here and there - constitutes around one QUARTER of ONE PERCENT of the total mass of that portion of the planet.
If we have a one km wave running over it, each wave would create one ONE HUNDREDTH of ONE PERCENT change of the total mass of the planet in that area.
If there as no land above the water surface, the depth of water would be <3km (from here, and see here for a graphical representation of the volumes), or less than 0.05 of one percent of the radius of the earth.
Tides would not be constrained by the continents, but the locations that currently have higher tides do so in part because of water trying to get through narrower gaps. I doubt we would have anything like a one km tide - and the wind required to cause that depth of wave would be astronomical. From here, the max wave height I can get for a 22,000 km fetch and a continuous (ever lasting - NEVER stopping) 100 knot wind is 200 m. This would be ONE FIVE HUNDREDTH of ONE PERCENT change of the total mass of the planet for each wave, which would occur around every 75 seconds.
I consider the idea that having all the land above water on "one side of the planet" or all the current volume of water in a single ocean could significantly affect the rotation / stability of the Earth to be, frankly, nonsensical.
See here for an explanation of effects on earth's orbit from a climatic perspective.
