It took me four days (a testament of how
massive where IJN major refits and recontructions) but here is finally Mutsu as of 1937:
Between september 5th 1934 and september 30th 1936 Mutsu was refitted at the Yokosuka Navy Yard, when the refit ended she was nearly a colpetely different ship, with maybe only the propeller shafts where left untouched...
The hull was lenghtened by 9 meters, a triple bottom fittend and massive torpedo bulges increased the beam from 29 to 33 meters, al the 20 original steam boilers where removed and replaced with ten oil-fired boilers, the fore funnel was removed while the aft one moved slighty forward; the mainmast was cut down heavily, both fore and aft superstructures where massively enlarged, especially the first where the heptapodal mast was incorporated into a massive pagoda mast towering 41 meters above the waterline, displacement rose by 6.533 tons to a standard of 39.050, maximum speed dropped from 26,5 to 25 knots.
The searchlight platform already positioned abreast the aft (and now only) funnel was enlarged to make space for an extra set of searchlights, new rangefinders where fitted, casemated guns modified in order to increase elevation to 35°, the four twin 5-inch (127mm) guns where left untouched, altough their platforms where slighty modified, the main guns where instead colpetely replaced, both Nagato and Mutsu recieved the turrets built during the 20's for the canceled Tosa Class battleships, wich had a maximum elevation of 43°; airwing was composed of three Nakajima E4N.
A little extra explanation: given photographic evidence it seems that Mutsu did not recieve 25mm machine guns untill at least late 1938/early 1939, but given the time the refit was implemented it's a little hard to believe that she was not fitted with light Anti-aricraft weapons at all, so i've put a 13mm Hotchkiss mount where the old 40mm Vickers machine guns where: on the shielded platform near the boat-handling area.