How will a DUI affect my chances at making E7?

This will be something considered. It all comes down to the board members and how they weigh it. Showing you were able to overcome this is key. NCOERs are crucial to showing growth.

Having sat a number of boards, including E-7/8/9, it will depend on several factors. Number in your designator under consideration (zoned etc.), number to select, what the precepts say is important, fair game, off limits for Board consideration, etc. Decline in performance trend not supported by things like forced redistribution of grading, etc. will be a negative. Static grading/performance is a red flag. Given all that, it's what the reviewers see and present for each crunch. One thing for sure, if there isn't a negative about it, board members are prohibited from bringing it up if they know about it. A thing in your favor is time. Shrewd reporting seniors who want to see you make E-7 will have grading and commentary that offsets prior negative information. Seeing where you are on the comparative spread and reporting senior average is important. Although Navy, we all have to follow the DoD Inst. Variation amongst the Services relates to stuff that is unique to the Service. For the Navy, there can be a difference with deployed vs. homeport paper even with the same reporting senior. There's guidance with how the Board looks at that. Although you say you have good evals, I know a ton of ways to stealth kill a career and the same number of ways to push the plus button. Words like "when due", "effective", and others in certain context is a stealth kill. Words like "exemplary", "beyond", "gold standard", etc. are pluses. Bottom line, it will depend where you shake out in the pool, everything given. Good luck.

In talking with previous board members they said negative information is less important the more time goes by, and that it is required for the board to review it. Even if it was when you were a PFC the board members are required to open and view the negatively filed information