From: Land o' Lakes, FL
The rub on replentishing ships at sea (using their own fuel), is that bigger refuels smaller, if even to a fault. If you press that "refuel at sea" button too many times during your trip, eventually your CVs will drain their own tanks (and depleat your ops points), and you'll be left with a CV with 1800 fuel in the middle of no-where. There will no one to refuel your CV (you're the largest ship), so you get stuck moving 1/0 - which tends to be very hazardous.
Wherever my CVs go, there is always a replentishment TF in the wake somewhere farther back. I also keep one fueled up at Pearl to top off the destroyers on ASW patrol topped off, and to sprint out to refuel somebody who runs out of gas down near the Line Islands. And RN ships tend to have fairly sucky range, so a replentishment TF just for them is a good idea as well.
"It is obvious that you have greatly over-estimated my regard for your opinion." - Me