CAPTAIN’S LOG

20 January 2015

We are doing our island hop leg of the SeaTterm.  Puerto Rico is now astern of us we steam toward St. Croix. As we move along the way to St. Thomas we’ll pass close to Nevis, St. Barts, Monserrat and others. The weather is nice, a little chilly under cloudy skies, with a north easterly breeze.

We prefer to steam at an economical rate, notice I did not say speed. Because we are a self-sufficient city at sea, making our electricity, fresh water, treating waste water and keeping all personnel cool (or warm) – there is significant decision making going on in the engine room operations. One element
is steam condensing.  The main condenser brings “used” steam in for the turbines, pumps and auxiliary systems, into a massive heat exchanger – where the steam meets the relatively cool ocean water – and brings the steam back to liquid form once more.  This requires a significant flow rate of sea water. When running slowly or in port, a large pump must move the sea water, but at sea
we can direct sea water passing the moving hull into the condenser via a big pipe called the “scoop”.  I we desire to sue the scoop the ship’s movement has to be about seven to eight knots.  So, we need that speed.

Mayaguez and St. Thomas are separated by only 120 miles. But keeping the ship moving to maximize deck an engineering training at an economical rate, we’ll travel nearly 500 miles.  That seems like an incredible increase,especially when the ship burns about 50 gallons of fuel per mile. But that is one element in the cost of our training operations.