Sorry, I missed your comment. To answer your first question, a significant amount of RCS for a capable commercial radar, not least of all because it is rounde

Sorry, I missed your comment. To answer your first question, a significant amount of RCS for a capable commercial radar, not least of all because it is rounded for hydrodynamics, which is a terrible shape for minimizing RCS. Second, I should have been clearer: the submarine stands to gain by operating their own radar rather than working from sonar alone. Finally, submerged transits are mostly advantageous for security concerns.