A submarine's ability to remain unseen makes routine public signaling costly. Surfacing identifies its location and can give nearby acoustic sensors a starting point for identifying its signature. It also tells other observers where that boat is not operating. For a small force with only a few submarines available, one appearance can reveal a substantial share of its dispositions, especially when other boats have carrier or deterrent-support duties. Larger submarine forces can absorb that loss of uncertainty more easily. An appearance can still have a purpose when it demonstrates access to a location where an opponent did not expect a submarine.
Notable Point · 2:21:58-2:24:42
What a submarine reveals when it signals its presence
Surfacing can demonstrate reach, but it also reveals location and reduces uncertainty about a small submarine force.