First of all, thanks for all your inputs, they make me learn from all. This was a “what if” game and I didn’t want to extend too much in my previous post. Supporting my idea, let me drop a few more comments…
One point is that I saw 17 knots somehow slow compared to the 2x4.5 MW motors. Then I was not sure if it was due to the hull shape or to the propellers (fixed or variable pitch? optimized for low speeds because of ice? – I also don’t know) . For an ocean going tug and submarine rescue ship, I considered 3-5 additional knots would help. I intentionally used conditional (“maybe propellers and prop. system should be also reviewed”) meaning that it should be studied both in terms of Navy needs and technical feasibility without introducing major changes/risks on the design. Sorry that I was too brief in my post.
Same way applies to the ice thickness. If it were as easy as just to use a thinner layer of steel in the hull (probably not), and if the Navy would not require these two ships for full Arctic environment, then they could be redesigned for 70 cm instead of 120 cm. Please remember that in the game we had no problem about money and had time enough untill mid 2020’s, when we would find the production gap, to make such redesign.
Crane (for SUBSAR) - I read sweeds using a 55 tons, A-shaped crane for their Sub-rescue ship, Korea uses an A-shaped crane as well. Might it happen that the 20 tons crane of the AOPs would not serve for the purpose? Is it really required an A-shape crane? and is the AOPS crane of such type?
Towing- of course any ship can tow. However, other navies (US, France, Russia, for instance) do operate oceanic tugs (UK relies on a Forward repair ship listed in the RFA), relieving other ships from such task.
Range and payloads – Good to know about the SUBSAR & SUBSMASH payloads! Then it wouldn’t be necessary too much of special design for the AOPS platform. On the other hand, since these 2 additional ships would not need to cover the Arctic, then it might be useful to redesign the hull for ocean-going (and benefit from a “lower” [1] polar class). Good also to know about the 4 months endurance of the AOPS (I had no data on that). But still 6500 nmi might be reviewed acc. to the needs and requirements of the RCN. IMHO it might be a little bit short to properly cover the Pacific without refueling in the way to assist to the distressed vessel. Vancouver to Sidney distance is about 6.700 nmi straight [2].
While I had in mind to use as much as possible an existing platform (the AOPS) and cover a possible gap in the Navy’s fleet, from the comments received it becomes clear that such ships (2x submarine rescue & oceangoing tugs) should better be designed from a blank sheet.
[1] Lower as less restrictive, therefore, higher number.
[2] Yeah, the range depends on the cruise speed as well. I’m primarily pointing to the RCN to determine the targeted range for such SUBSAR & Tug duties, and secondly expressing that IMHO 6.500 nmi would not suffice.
Sorry for this loooong post. And thanks again for your comments.
One point is that I saw 17 knots somehow slow compared to the 2x4.5 MW motors. Then I was not sure if it was due to the hull shape or to the propellers (fixed or variable pitch? optimized for low speeds because of ice? – I also don’t know) . For an ocean going tug and submarine rescue ship, I considered 3-5 additional knots would help. I intentionally used conditional (“maybe propellers and prop. system should be also reviewed”) meaning that it should be studied both in terms of Navy needs and technical feasibility without introducing major changes/risks on the design. Sorry that I was too brief in my post.
Same way applies to the ice thickness. If it were as easy as just to use a thinner layer of steel in the hull (probably not), and if the Navy would not require these two ships for full Arctic environment, then they could be redesigned for 70 cm instead of 120 cm. Please remember that in the game we had no problem about money and had time enough untill mid 2020’s, when we would find the production gap, to make such redesign.
Crane (for SUBSAR) - I read sweeds using a 55 tons, A-shaped crane for their Sub-rescue ship, Korea uses an A-shaped crane as well. Might it happen that the 20 tons crane of the AOPs would not serve for the purpose? Is it really required an A-shape crane? and is the AOPS crane of such type?
Towing- of course any ship can tow. However, other navies (US, France, Russia, for instance) do operate oceanic tugs (UK relies on a Forward repair ship listed in the RFA), relieving other ships from such task.
Range and payloads – Good to know about the SUBSAR & SUBSMASH payloads! Then it wouldn’t be necessary too much of special design for the AOPS platform. On the other hand, since these 2 additional ships would not need to cover the Arctic, then it might be useful to redesign the hull for ocean-going (and benefit from a “lower” [1] polar class). Good also to know about the 4 months endurance of the AOPS (I had no data on that). But still 6500 nmi might be reviewed acc. to the needs and requirements of the RCN. IMHO it might be a little bit short to properly cover the Pacific without refueling in the way to assist to the distressed vessel. Vancouver to Sidney distance is about 6.700 nmi straight [2].
While I had in mind to use as much as possible an existing platform (the AOPS) and cover a possible gap in the Navy’s fleet, from the comments received it becomes clear that such ships (2x submarine rescue & oceangoing tugs) should better be designed from a blank sheet.
[1] Lower as less restrictive, therefore, higher number.
[2] Yeah, the range depends on the cruise speed as well. I’m primarily pointing to the RCN to determine the targeted range for such SUBSAR & Tug duties, and secondly expressing that IMHO 6.500 nmi would not suffice.
Sorry for this loooong post. And thanks again for your comments.
