Mackinaw?

[Odysseus]

I'm in agreement about any sort of "twin" to the current Mackinaw 30.

When I first heard about the whole idea of azipods for propulsion, I was wondering what they were thinking. Great Lakes ice issues are not always plate ice issues, or issues with ice piling up in windrows. More often than not, we see ice that is slushy and brash, which can cause problems as I see it with propulsion systems. Ice gets caught under the bow, stuck in the pods, and probably screws (no pun intended) up the pods,

A fixed screw with ample HP and a wide enough beam is what's needed. Add in the bubbling system the 140's have if need be.

The Mackinaw 30 seems more like a middle-weight when it comes to the ice issues we've had these past two years.

Based on the ice issues for the years before she was commissioned, it makes sense why they would have ordered her. But given the past two years, it seems like they underestimated the future needs.

[Jon Paul]

I think the Coast Guard should nicely ask our Canadian neighbors to borrow the plans for the Pierre Radisson and make a copy of it. I don't mean any disrespect to any USCG people who are reading this, but since the original Mac was retired it seems like any time some serious icebreaking needs to be done on the lakes it's up to the Risley, Martha Black or the Radisson to get the job done.

Im not sure I would include the Risley and Black as serious heavy icebreakers. The Risley spent several days last week trying to open Whitefish Bay and didn't get anywhere till the Radisson showed up.

[Guest]

I think the Coast Guard should nicely ask our Canadian neighbors to borrow the plans for the Pierre Radisson and make a copy of it. I don't mean any disrespect to any USCG people who are reading this, but since the original Mac was retired it seems like any time some serious icebreaking needs to be done on the lakes it's up to the Risley, Martha Black or the Radisson to get the job done.

[guest]

The current Mackinaw by no means has the ice breaking abilities as the original Mac. There are those who classify her as a heavy ice breaker which is not the case, she is more of a medium to medium/heavy class ice breaker. The USCG was informed when the current Mackinaw was proposed that it wouldn't be sufficient for Great lakes which has been proven. So what is really needed is a "Heavy" ice breaker committed to the lakes instead of a second Mackinaw as we currently have as the LCA has proposed.

[Firemedic026]

The general principle of ice breaking is no drag on the hull. When they were designing the MAC "chief" told them over and over that azipods were a bad idea for use on the lakes given the ice conditions can dramatically change from year to year. One of his original designs was a twin screw 18000 hp diesle electric plant with fixed pith pitch props. Azipods belong on cruise ships in the tropics not an ice breaker on Lake Superior

[Al]

Article and video about the Mackinaw, saying it might return to service Friday: http://www.9and10news.com/story/2871004 ... ng-repairs

[DocF]

Virtually all of the cruise ships that have azipods from ABB have had seal and/or bearing trouble. Rather than being an issue with lack of familiarity with this style of propulsion, it is, in my opinion, an issue with the manufacturer.

Now to be fair, Rolls Royce, another major builder of azipods, has had even more issues with theirs.,

[The Schipper]

They use that system in parts of the world that have ice anywhere from 9-20 feet thick with no problems moving in the ice and that the reason it seems the Mack has problems is that they truly do Not know how to effectively use the Azipods to full efficiency and capabilities. Boats that have the Azipods chopped up and moved thru 10 feet of ice with no problems.

[MattJ]

Following information is about capabilities ofMotor Tanker Mastera a finnish double acting tanker. And Azipods are far superior to conventional propulsion systems as attested to the thickness of ice she can break through.
The icebreaking capability of the double acting tankers proved to be superior to other ships since the beginning — in shuttle service between Primorsk, Russia, and the Finnish refineries the tankers require no icebreaker assistance and have even acted as an icebreaker for other merchant ships that have utilized the wide channel opened by the Aframax tanker.
The ships have performed beyond expectations in both level ice up to 1 metre (3.3 ft) thick, which can be broken in continuous motion at 3 knots (5.6 km/h; 3.5 mph),[8] and ridges up to 13 metres (43 ft) deep, which can be penetrated by either allowing the forward-facing propeller to mill (crush) the ice or breaking the ridge apart with the propeller wash.[15][29] While the vessels have been immobilized occasionally by pack ice, they have been able to free themselves by using the rotating propeller pod to clear the ice around the hull.[30]

[MattJ]

Because of the limitations of traditional propulsion systems, the double acting ship concept wasn't seriously considered until the development of electric podded propulsion units which combine the advantages of the diesel-electric powertrain, already widely used in icebreakers, with the excellent manoeuvrability of azimuth thrusters.[1] Initially developed as a co-operation between the multinational electrical equipment corporation ABB Group and the Finnish shipbuilder Masa-Yards in the late 1980s, the new propulsion unit became known as Azipod (a portmanteau of "azimuth thruster" and "podded propulsion unit") which is today a trademark of ABB Group.[7]

The superiority of electric podded propulsion in icebreaking ships, especially when running astern, was proved when the first propulsion pod was installed on fairway maintenance vessel Seili, owned by the Finnish Maritime Administration, in 1990. Before the conversion the ship could not break ice astern at all, but after the propeller and rudder were replaced with an 1.5 MW Azipod unit she could run astern in level ice as thick as 0.6 metres (2 ft). The vessel could also easily be steered when running astern in ice. When product tankers Uikku and Lunni were converted to Azipod propulsion in 1993 and 1994, respectively, the result was similar increase in manoeuvrability and icebreaking capability. Even though the ships were originally designed with icebreaking capability in mind, after the conversion ice resistance in level ice when running astern was 40% of that when breaking ice ahead despite the ships being equipped with an icebreaking bow and not designed to break ice astern.[1][4]

Model tests conducted by MARC in 1994 showed that a double acting ship equipped with an Azipod propulsion unit could break through ice ridges in continuous motion instead of ramming like conventional icebreakers. It also required less power for running in level ice than traditional designs, resulting in 40–50% reduction in ice resistance due to lubricating effect of propeller-induced water flow, more open stern design and the propellers being allowed to mill (crush) the ice.[4] The icebreaking capability of an Azipod-equipped icebreaker operating astern in level ice was also found out to be superior to traditional icebreakers regardless of propulsion arrangement.[1]
I think this speaks volumes of using azipods in icebreaking vs traditional propulsion.

[GuestfromEU]

Fair enough, new technology is always difficult at the beginning. The problem is that azipod technology is not new technology. I worked with pods built 20 years ago, just as I now work with ones built less than a year ago. The design really hasn't changed - they are 95% the same. ABB/Rolls Royce has this technology down to a science. The problem here is that azipods are not the best choice for ice operations. The designers of the Mackinaw may have chosen the propulsion based on open water work, which is the majority of her time. Regardless, until a true all-weather multi-purpose boat is built, the USA will depend on the Canadian Coast Guard for icebreaking. In the grand scheme of things, perhaps paying the Canadians for their service is cheaper in the long run...

[Denny]

I would say now that after reading today's news of the Mackinaw and her problems and issues, the call and debate to build more and new icebreakers for both the U.S. and Canadians will raise a few new eyebrows! Also, I would say that we should really start to hear more on the issue from the LCA and the shipping firms to lobby and have authorization to build and construct new ones. I don't see that happening for a while only because the New Mackinaw just built in the past 10 years or so give or take. I am sure congress is not too eager to have the CG build and construct any new vessels in the near future but, that is just my opinions only on this subject.

[wlbblw]

Chalk it up to teething problems. Every new technology has bugs. Whatever ship was first to employ the old Mackinaw's tech probably spent some time in the yard getting it right. If we were talking about the 5th one of her class breaking down, yeah, ok to complain, but she's the 1st. That's just the way of it. Try again next year & do better then.

[Guest]

So much for modern technology. When the job calls for a simple work horse you use a simple work horse. A new, basic, simple powerful Mackinaw is needed if the US wants to stay in the ice breaking business.

Workhorse like the Samuel Risley. That boat has been everywhere.
Mackinaw can go back to buoy work.

[drydock]

So much for modern technology. When the job calls for a simple work horse you use a simple work horse. A new, basic, simple powerful Mackinaw is needed if the US wants to stay in the ice breaking business.

[edm]

nice picture of her at the west pier in the soo in the photo gallery.

[Guest]

So any reliable info out there about how badly the Mackinaw is broken?