sentences:  After "Deutschland", which had a mixed set of fire-tube and water-tube boilers, the remaining four members of the class received a uniform set of water-tube boilers.These were lighter, and the weight savings were passed on to the armor layout in the form of a slightly thicker armor belt and a strengthened upper deck.The "Deutschland" design was criticized in Germany at the time the ships were being built, as the trend in all the major navies pointed to battleships armed with all-big-gun batteries; indeed, work on what would become the of dreadnought battleships had already begun in 1903.