Each tank vessel having a COW system under Sec. 157.10(e), Sec. 157.10a(a)(2), or Sec. 157.10c(b)(2) must have a means that enables two-way voice communications between the main deck watch required under Sec. 157.168 and each cargo discharge control station. [CGD 82-28, 50 FR 11628, Mar. 22, 1985]