A few thoughts about tugs:

As I've been reading Beans, Bullets, and Black Oil, a 1952 book about logistics in the Pacific in WWII, I've been struck how often the topic of tugs has come up: ships that were saved because of their presence, or perhaps lost due to their absence.

Some examples that jumped right out: that the carrier USS Yorktown might have been saved at Midway, had the Navy yet appreciated the value of fleet tugs.

That the carrier USS Hornet and destroyer USS Porter might have been saved at the Battle of the Santa Cruz islands if tugs had been available:

And that tugs were able to help save three heavily damaged cruisers after the Battle of Tassafaronga:

By my count it looks like the USN started WWII with 20 or so ocean-going tugs (ATs) available. And then over the course of the war, as lessons were learned, the USN built 200+ more (ATAs and ATFs), many of which served for decades more.