Complex sentence: Between rescuers and survivors, the "R.B. Forbe" was overcrowded, leaving little room to work the oars; the overcrowding also made the boat even more difficult to manage.
Split into simpler sentences: Between rescuers and survivors, the "R.B. Forbe" was overcrowded, leaving little room to work the oars. The overcrowding also made the boat even more difficult to manage.