Zulu time is a standard naval and aviation time based on what was once called Greenwich Mean Time. A very very basic explanation of it is as follows. Based on where you are in one of the world's time zones you add or subtract 1-12hrs from the stated Zulu time. For example, when time is shown as 1430 Zulu while at JAG headquarters 5 hrs is subtracted. Meaning, it's 0930 in Falls Church, Virginia. So even though the time shown was 2223 Zulu when the money was delivered, based on their location it is reasonable that it is daytime.
The fictional submarine here is USS Crawford (SSN-806). No such ship exists. However, there was once USS Crawford (SP-366), originally a commercial tugboat (as a property of the Erie Railroad Company), which became converted into a minesweeper, which thus served 1917-19. In the US Navy the submarine with the highest hull number is USS Delaware (SSN-791).
In the scene following Harm's "I'll be back", a Champion Crane is visible in the background. Such a crane featured in 'Terminator 3: Rise of the Machines' (2003), the last film from the series that originated that phrase.
The aircraft carrier in this episode, CVN 69 USS Connolly, is actually the USS Dwight D. Eisenhower.
The fictional aircraft carrier here is USS Connolly (CVN-84). The real USS Connolly was DE-306, a destroyer escort of the Evarts class, which served 1944-45. The real Connolly provided protective patrol services during the amphibious landings involved with the Battle of Iwo Jima. CVN-84 does not yet exist in the US Navy. The carrier with the highest number is CVN-80, still in planning, to become named as Enterprise.