In case anyone is interested:
The secchi disk was invented by the Italian Astronomer Pietro Angelo Secchi circa 1860. In 1865, Pietro Secchi was asked to assist the commander of the papal ship S.S. I'Immacolata Concezione in measuring the transparency of the coastal waters of the Mediterranean Sea. Secchi experimented with two types of disks, a 43 cm disk of white clay and a 60 cm diameter disk of sailcloth painted white and stretched over an iron ring. Secchi lowered the disks until they became invisible; this depth was thereafter known as the secchi depth. Secchi tested brown and yellow disks; occasionally he would shade them from the sun with umbrellas or hats. He also tested variations in the secchi depth in calm and stormy waters.

Good morning Dave, I've checked the ships systems, and everything appears to be running normally.