I wasn't thinking of using the water like an ablative expended shield, the water stays in the jacket layer it only prevents the titanium hull from melting the way water inside a pipe keeps it from getting hot enough to melt solder. You can place a water filled waxed paper cup on an open fire and it wont burn up.

I did consider that there might be a problem of creating steam and the pressures involved, but wouldn't it have to have air in the jacket to be able to turn to steam? I also considered the problem of the water freezing in orbit but heaters could prevent that or perhaps an oil substitute or maybe even ethylene glycol.

The vacuum layer and other insulation insulates the crew from the heat that is built up until it can be dissipated when the craft reaches the more dense layers of the atmosphere.

The design also relies on the floating paper like effect because of the large diameter so it doesn't fall as fast therefore less heat is generated.

Would a huge cone shaped piece of card board burn up on reentry?
I don't think it would. The floating principle is the same although the engineering is different. I'm not suggesting that card board be used as hull or ablative material.