Naval types: What part of the ship is this?

Calling all naval types . . .

In preparation for my dad’s memorial service, we are going through old pictures and mementos. One interesting item is a note card with a picture of the ship my dad served on in the Navy in the late 1950s:

USS Prichett

Inside the note card he wrote: “See that little arrow under the pix? That’s the 56 director way up there, behind the after stock. I know, I’ve scrubbed it many times.”

I’ve drawn in an arrow pointing to the part that his arrows (not in the scan) indicate.

OK, so what’s the 56 director and what does it do?

Thanks much.

I’m a Navy brat. Does that count?

The ‘56 director’ is a Mk. 56 Gun Fire Director.

Oh – I’m pretty sure that’s ‘after stack’, not ‘after stock’.

Four minutes. I love the SDMB! Thanks, Johnny!

OK, looking at the handwriting again, it could be a sloppily written “a”. The amazing thing is that the handwriting of his that I knew was a practically unintelligible scrawl. This note is written in fairly neat cursive. I would never have thought he wrote it. Obviously he was much younger then. (I’m sure his mother, who was a schoolteacher, was appalled if she ever saw his older handwriting.)

Further commentary is more than welcome, of course!

Here’s more about the Mark 56 Gun Fire Control System than you probably need to know. Basically it’s a narrow-beam radar feeding an analog computer that aims the ship’s 5" guns.

Here’s the Wiki article on the USS Prichett.

Note that while Wikipedia accurately notes that the Prichett was a Fletcher Class destroyer, which accords with the description of “5 × 5 in./38 guns (127 mm)” in the armaments section, the 56 Director actually replaced the number 3 mount, (the one just aft of amidships that faced forward), during the 1952 modernization. (The Navy apparently figured that greatly improved accuracy compensated for a 20% reduction in firepower.)