Some of my best friends on Saipan have been captains of the nautical stripe. Many are quite adventurous, and spin great yarns about distant shores that I\u2019ve yet to visit, such as the Solomon Islands, the Marquesas Islands, and such. On the tamer end of the spectrum, some of my relatives just took their first ever cruise ship excursion (in Alaska); they were so impressed with the operation that they suggested it would make a good column on how solid customer service makes for happy tourists. <\/p>\n
I said OK, but as I prepared that work, I veered into an engineering caper that\u2019s pretty cool. <\/p>\n
I was looking over a passenger\u2019s \u201cCruise Log\u201d from the MS Oosterdam, part of the Holland America Line. The log is one of many nice touches for the passengers, a simple little summary of where they went, distances, speeds, and such. The back of the log has a summary of the ship\u2019s engineering; this is a monster of a ship, displacing 82,000 tons, which is on par with some aircraft carriers. <\/p>\n
Here was the caper, and you ship guys will appreciate this. Under the \u201cpower\u201d section of the engineering summary, it lists five \u201cdiesel generators,\u201d plus one \u201cgas turbine.\u201d From the way that\u2019s worded, I assumed that the diesels are making electricity, and the gas turbine (which is basically a jet engine that drives gears) was used for propulsion, though the turbine struck me as way too puny for that job. Things didn\u2019t add up.<\/p>\n
I got even more confused when under \u201cpropulsion\u201d the listing was this: \u201c2 x ABB Azipods.\u201d<\/p>\n
Azi-what? What\u2019s going on here? What\u2019s going on is that the modern age has, yet again, leap-frogged right over my head.<\/p>\n
Conventional ship propulsion is sort of like a pickup truck. You\u2019ve got a power plant (engine), which drives a shaft, which goes to a transmission, which reduces the RPMs, which drives another shaft, which drives, instead of tires, the propeller (a\/k\/a\/ \u201cscrew.\u201d) That\u2019s what car people call the drive train. <\/p>\n
As for power plants, I\u2019ve been to sea aboard nuclear, diesel, boiler, and gas turbine varieties, but, regardless of the power plant style, the basic concept of drive trains is (OK, was) still the same. <\/p>\n
Well, along comes the Azipod, a trade name for a Swiss company called ABB. <\/p>\n
You\u2019ve heard of fly by wire? This is thrust by wire. <\/p>\n
An Azipod is a submersed pod that contains an electric motor and a propeller. On the examples I saw on Internet photos, the ships had two such pods, each of which could swivel, and each of which was mounted outboard of where the ships\u2019 rudders would be. I say \u201cwould be\u201d since the swiveling Azipods serve the purpose of a rudder. <\/p>\n
So there\u2019s no mechanical drive shaft between the ship and the propellers. The ship\u2019s engines drive generators (hence that \u201cdiesel generator\u201d phrase that I had encountered; the gas turbine also drives a generator), which (of course) produce electricity, which is (of course) run to the Azipods. <\/p>\n
The propellers, incidentally, are fixed-pitch, not variable-pitch. <\/p>\n
The Azipods must pack some muscle: According to the cruise log, the MS Oosterdam was making good 22 knots along parts of its voyage. That\u2019s a hair over 25 miles per hour. Not too shabby! <\/p>\n
This isn\u2019t just a civvy thing. The U.S. Coast Guard uses Azipods on one of its ships, the USCGC Mackinaw (WLBB-30), which was commissioned in 2005. <\/p>\n
I\u2019m pretty much a nut for anything that moves: Ships, planes, helicopters, cars, you name it. Maybe that\u2019s because I just can\u2019t sit still. I prefer to be moving. Some other folks do, too, but in this sedentary age, I suppose we\u2019re a dying breed. Hopefully, Saipan will always have some captains as part of the local color, who can provide perspectives too big to be held in cubicles.<\/p>\n
****<\/p>\n
[I]Ed is a pilot, economist, and writer. He holds a degree in economics from UCLA and is a former U.S. naval officer. His column runs every Friday. Visit Ed at TropicalEd.com and SaipanBlog.com.[\/I]<\/p>\n","protected":false},"excerpt":{"rendered":"
Some of my best friends on Saipan have been captains of the nautical stripe. Many are quite adventurous, and spin great yarns about distant shores that I\u2019ve yet to visit, such as the Solomon Islands, the Marquesas Islands, and such. On the tamer end of the spectrum, some of my relatives just took their first ever cruise ship excursion (in Alaska); they were so impressed with the operation that they suggested it would make a good column on how solid customer service makes for happy tourists.<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4],"tags":[],"class_list":["post-126567","post","type-post","status-publish","format-standard","hentry","category-local-news"],"_links":{"self":[{"href":"https:\/\/www.saipantribune.com\/index.php\/wp-json\/wp\/v2\/posts\/126567","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.saipantribune.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.saipantribune.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.saipantribune.com\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.saipantribune.com\/index.php\/wp-json\/wp\/v2\/comments?post=126567"}],"version-history":[{"count":0,"href":"https:\/\/www.saipantribune.com\/index.php\/wp-json\/wp\/v2\/posts\/126567\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.saipantribune.com\/index.php\/wp-json\/wp\/v2\/media?parent=126567"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.saipantribune.com\/index.php\/wp-json\/wp\/v2\/categories?post=126567"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.saipantribune.com\/index.php\/wp-json\/wp\/v2\/tags?post=126567"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}