Motorized bow enables tugboat to break ice up to 70 cm (2.3 feet/27.6″) thick
MarineLog reports progress on this. We talked about this earlier, looks like this is happening. This description from the earlier report.
Danfoss Editron’s hybrid electric system will powering the removable bow with two generators, built as a DC system, and two propulsion systems. In addition, the company has provided a front supercapacitor so that peak powers can be efficiently controlled. The Editron software also cuts fuel consumption and delivers high efficiencies as the diesel-generators in the DC system can be driven at variable speeds.
Lake Saimaa, where it operates is not very large. Looks like it is about 40 miles from corner to corner. Note while the tug pushing it is not an icebreaker, it is ice strengthened.
Below is a comment on the earlier post by, Tups, a Finn, and our resident icebreaker expert.
“… the technology is easily scalable and, since you don’t have to worry about seakeeping during the open water season – you can go for a slightly more “extreme” icebreaking bow to increase the performance at the cost of slamming impacts in head seas. Perhaps this could be a solution for commercial (contracted) icebreaking in the Great Lakes?
“By the way, this relates to another post you published some time ago – the tug that pushes the removable bow is the one that was fitted with the new ice-strengthened bronze propellers.”
Chuck Hill's CG Blog 
Marinette Marine had a patent for a self-powered icebreaking bow attachment, but it expired in 2016:
https://patents.google.com/patent/US5660131A/en
In the patent drawings, the detachable icebreaking bow is shown attached to a USCG Juniper-class buoy tender, showing its potential for scalability.
Imagining the possibility of this concept for the 140 WTGB replacement (eventually). Icebreaking section for winter and buoy tending/construction section for summer. ATB connections have come a long way since the USCG started pushing the ATON barges with the 140. That soft line system was always problematic in a seaway. A system could be designed that had nearly the breaking power and width of the Mac and allow a much smaller and easier to maneuver crane bow for summer. The 140 is a great small breaker but pretty bad at everything else.
During the full-scale ice trials last spring, the “add-on icebreaker” broke almost 24-inch ice at 4.7 knots:
Click to access Passion_news_2021_nro_02_12_13.pdf
That falls somewhere between the 140′ WTGBs and USCGC Mackinaw.
@Tups, thanks, that is impressive.
@Tups, This is, as I recall, like the Great Lakes, fresh water?
Yes, Saimaa is a freshwater lake.
as i mentioned quite awhile back. the uscg has done this before. without digging out my uscg cutters and craft of ww2 book, this was tried before. if i remember right it did not catch on. now we all know tech has improved so don’t know how it would work today. ice plow. used in upper mississippi, pushed by cgc fern. page 90, u.s. coast guard cutters and craft of ww2.. ok, i dug out the book because it bugged me. for those that have it. like i said that was the 40s sure the tech has improved a lot. it doesn’t say if the fern’s plow was the only one used though i get that impression.
Of course I have Coast Guard Cutters and Craft of WWII also.
Looking at the Fern’s arrangement their are substantial differences.
In the case of the Fern it gave a typical blunt bowed pusher tug a sharp bow and also made it wider to clear a wider path.
Unlike the Finnish system the add on bow was not powered.
kinda figure you have the book chuck what coastie who likes our ships and history doesn’t? i also mentioned the tech is much different now. read the piece though not easy even with my glasses. 😉 why self propelled? not sure. easy to marry the pusher to the plow? obviously not going to send the plow without the pusher. maybe i missed something.
@bigsbigs1. I am sure Tups has better information but apparently the icebreaking bow is powered to provide additional power and better maneuverability. Also means less pressure on the connection between tug and bow piece.
The removable icebreaking bow in itself is indeed not a new invention; this is probably the oldest example I have come across:
However, it’s quite likely its primary purpose was to protect the hull of the tugboat rather than facilitate icebreaking. It’s difficult to say where the photograph was taken; if I had to guess, I’d bet on one of the large European rivers.
Anyway, I just noticed that some video footage of the full-scale ice trials has been uploaded to YouTube:
I would say the primary reason to add propulsion to the detachable bow would be simply to provide more power and thrust to increase the combination’s icebreaking capability – after all, you’re increasing the width of the broken channel so you might require some “boost”. Depending on how the power is put to the water, the additional propulsors may also increase maneuverability and divert the broken ice under the surrounding ice sheet. However, if the pushing vessel is for example a powerful high ice-class azimuth stern drive tug, it may be better to leave additional propulsion out.
Oh, and while everyone talks about “self-propelled icebreaking bow”, I heard that while it’s theoretically possible to drive the bow without the pusher tug, it would be a very interesting exercise as you’d have to steer with differential thrust, the directional stability would be horrifying, and you couldn’t see out from the emergency control position…
Not the best picture to show off the configuration, but I did find a picture of Fern with iceplow here. https://www.ebay.com/itm/LG822-1946-Orig-Photo-COAST-GUARD-ICE-BREAKER-FERN-United-States-Military-Ship-/363091223092