I’ve seen hovercraft used to pre break the ice on the St. Lawrence River. The air under the skirts forces down through cracks in the ice, either natural or created by the over pressure. This creates big air pockets under the ice, and it collapses under its own weight. Then a conventional ice breaker or even just a sturdy lake freighter (the old ones have thicker plating than most ocean goers), can push its way through the broken ice, as long as they come along in the wake of the hovercraft before it refreezes.
Thank you! I've been waiting for icebreakers ever since i requested it, iirc in 2020 Feb. And i've been subscribed all that time, in fact i think i found your channel back in 2017 and subscribed almost immediately. By far the best marine engineering channel i've found, to this day. If you don't mind a followup q, how thick do they make the hull (compared to normal ships) and has this changed much from the earlier years? Also interested in what kinda extra maintenance on the hull is needed.
Thickness varies depending on the ice they are designed for. For the Mackinaw, her hull plate was 41 mm (1-5/8 in.) thick. The other factor is the stiffener spacing. On some bigger icebreakers, the bow stiffeners are so close together that you can barely fit your hand between them. I don't have specific details for extra maintenance on the hull. But I expect a lot more focus on the hull during daily inspections. Checking for cracked welds. Another factor is the vibration. Breaking through ice can vibrate the hull violently. There are stories of bulbs breaking and equipment getting damaged just from the vibrating hull.
@@DatawaveMarineSolutions Great to hear there will be another vid on them. I first got interested from reading about Soviet icebreakers, which later became nuclear.
I was at a shipyard earlier this year and the ship that was in the dry dock next to us was nunavik which had a spoonbow that was really impressve. she has ice class IACS Polar Class 4 according to wikipedia
When you said museum piece I was worried you were refering to the Canadian coast guard's Louis S. St-Laurent. As well, museum piece is rather apt name for our current flagship from the 60s...
I recall that the SS Stockholm which collided with the Andrea Doria had an ice breaking bow. Is that true and if so how was she able to manage transatlantic crossings?
My information may be wrong, but I remember that the SS Stockholm wasn't an ice breaking bow, it was ice strengthened. I know, we make these terms similar enough to sound the same. But they are different. An icebreaker goes into virgin ice fields and cracks through, creating a channel for regular traffic. The ships that follow in the channel are ice strengthened. Their bow isn't shaped for icebreaking. They don't have rounded hulls. They are normal ships intended for open ocean service. The hull is just a little stronger in case they hit a stray piece of ice left in the channel.
i Finally started drafting up a rough design in autodesk in my spare time... not very far along on it. while i was working today i thought about how i might send the file for you to look at some of the concepts i wanted to incorporate in it... the thought of you looking at it and letting it pass you by crossed my mind, then that it might cause a coronary... Best of luck Nick. If i ever make it to Florida i might look you up.
