I think you guys who are saying 6" guns will 'hound' Incomparable better have a read of its proposed statistics:
General characteristics
Displacement: 46,000 long tons (46,738 t) standard
Length: 1,000 ft (304.8 m)
Beam: 104 ft (31.7 m)
Draught: 24 ft (7.3 m) (at deep load)
Installed power: 180,000 shp (134,226 kW)
Propulsion: Brown-Curtis geared steam turbines, Yarrow boilers
Speed: 35 knots (65 km/h; 40 mph)
Range: 24,000 nautical miles (44,000 km; 28,000 mi) at 10 knots (19 km/h; 12 mph)
Armament:
3 × 2 – BL 20-inch (508 mm) guns
5 × 3 – QF 4-inch (102 mm) guns
9 × 1 – QF 3-pounder guns
8 × 1 – 18-inch (450 mm) torpedo tubes
Armour: Belt: 11 in (279 mm)
Decks: 4 in (102 mm)
Barbettes: 14 in (356 mm)
A full read of the Wiki entry may also help:
http://en.wikipedia.org/wiki/HMS_Incomparable
Incomparable was never meant to stand in the line of battle, it was designed like all Fishers battlecruisers, to 'scout', be the eyes of the fleet. To be able to brush aside the enemies scouting forces and lay eyes on the enemy fleet. The ship was armoured well enough to fulfil that role. Even had Incomparable been built it would have been superseded by the catapult launched and carrier borne aircraft for scouting duties.
An 11" belt was deemed thick enough to keep out the 12"-13.8" guns that the Admiralty believed were being fitted to the German battlecruisers in 1915-16, when Incomparable was first mooted.