Now that the game is in open beta, the changes that have been made to SOLs bring them back in line with the original concept. They will cost a lot more to make, and the items required to build them will vary in level, meaning that lower level players can contribute to the construction. Another change is that the difference in cost between Fourth, Third, Second, and First Rate SOLs has been increased. Because they were previously similar in cost, people would skip straight to the First Rate SOL, which really unbalanced things. Now there will be a bigger cost variance between these ranks of SOL, and the First Rate will be very expensive to fix after being damaged, making it a major decision on whether to bring one to a battle, or to stick with the less powerful but less expensive versions.
All of these changes have implications for various classes in the game. For example, the SOLs are one of the main reasons to become part of the Navy, so of course, this changes things for them in a big way. The full beta devlog has information on how the Navy will be altered with respect to the SOL updates, and how it will affect others as well.