Makes me wonder if the USN radar can see shells fly in the scope panel.

ezekill said:

Makes me wonder if the USN radar can see shells fly in the scope panel.

By 1943, yes.
The mid-to-late-war American Radar were perfectly capable of detecting both incoming and outgoing shells (and had to account for this unless they wanted to 'go blind' every time the ship fired off a salvo); this practice would later be built into radar/gun-fire control units (post-war radar/gfc) and by the '70s they were using these radar returns to correct for gun error on outgoing shells.

kibehisa said:

wasn't they also basing their firing according by straddle? aka the shots were almost/indirectly hit the ship?

T34/38 said:

wasn't they also basing their firing according by straddle? aka the shots were almost/indirectly hit the ship?

Well, yes, commonly both were/are done at the same time when inside radar range. Shot Watching (also 'Watching for Shot') tells you where you hit; Radar tells you where you are aiming at, where your shot is going, AND allows you to Watch for Shot beyond-visual-range.
So, even using Radar, they were still Watching for Shot as the Shell Splashes (shell impacts with the water) were visible on radar on higher-end surface/air radar.

This, of course, is not covering the various 'minor' problems with Radar, such as accuracy and the inability to see shell splashes on the immediate other side of the target.

This really should not have happened, considering that the Japanese were pioneers of radio technology with the Yagi antenna. Which they promptly forgot about until after the capture of Singapore, where they learned the British had employed the Yagi antenna in their radars... source paper

In the ultimate twist of fate, the two atomic bombs had Yagi antennas mounted on them to determine the bomb's altitude for a successful mid-air detonation.