Travis, the ships engineer in Enterprise put it like this,
"These engines damage the space time continuum"
I wonder if (big If here!) to produce a warp field, we could some how change the "phase" of the mass/time around the ship.
I'm not sure how to put this, but I liken it to the way a choke in a fluorescent light keeps the voltage and current in phase.
When you take out the choke, the light appears to be using less power, but only because the current and voltage are no longer in phase.
So, somehow, we "de-phase" the mass of our ship, making it heavier at the bow, lighter at the stern.
A bit like making a soap powered boat, where the soap changes the surface tension of the water its floating on.
Kinda like surfing a locally moving wave the ship generates, where "downhill" is always at the bow end of the ship.