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Post Info TOPIC: Power requirements
Sub Prime

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Power requirements
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Hi.

Love the site and love the subs. Amazing job. Bad weather avoidance, low fuel cost, no sailing experience required makes travelling the oceans as easy as using a canal boat.

The 20T is a beauty, she looks like an orca.

I have a few questions if that's ok.

Could you give me some idea of how much hp it would take to move the subs. I've read through the whale locomotion stuff and I think I've seen you say 400 hp would move the 200 ton sub at ~30 knots. Is this correct or is it 400 hp for the 20T sub? That's for below the waterline, correct?

Does engine size scale easily? If it's 400hp for 200T would you only need 40hp for the 20T to achieve the same speed? I love the idea of drift driving for free btw.

Can a sail be used? I think i've seen you post a pic of a sub with a sail and I've read the story of the Australian WW2 submariners who made a sail for their sub but I wonder if a sail can be used while the sub is actually submerged and what speeds it could achieve. I don't see any reason why it couldn't in theory but i know nothing about boats.

 

Slightly OT.

Hydrothermal vents. Have you any sources about using them as a power source. I've read through the mining articles but can't see anything relating to power. A 400C heat source seems like it would be a great power supply.

Clean water. I haven't seen any mention of using the deep, cold ocean depths to condense freshwater out of humid air. Couldn't cold water be pumped up through insulated pipe and run through a condenser, or humid air blown over a condenser at depth and then the condensed water pumped up.

https://www.windows2universe.org/earth/Water/images/temperature_depth.jpg

Temp. at 500m is ~12C, which would work ok for air of high humidity. At 1000m it's about 6C which would be great.



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Hello Sub Prime,

Welcome on the concretesubmarine forums. Thanks for your nice words. Yes 200 ton whale can make some 30 knots with 400 hp energy input and the same whale makes about 5-8 knots with 40 hp input. That works for a hydrodynamic body of some 20m length swimming submerged without creating surface waves.

I doubt that the 20 ton sub can go 30 knots with any amount of energy input. Speed is mostly a function of lenght. The 20 tonner had only 10m lenght i think 10-12 knots will be the maximum you can achive with an oversizzed engine.

Although it seems to be possible to rig a sail on a snorkel mast, and the pull of such a sail will surley be sufficient to make a reasonable speed, the sail handling seems a bit problematic. I would rather explore the possibility of making oceanic voyages in drift dives with the current all oceanic animals do that the Ben Franklin data suggest that this gives you logs very similar to a sailing yacht.

You drive your boat under diesel into the Gulf stream in Florida, and then just sit there until England comes up after 4 relaxing weeks reading a few books. You use the same free renewable energy as a sailing yacht but you avoid seasickness and sail handling - the annoying part.

I am sure hydrothermal vents will be a source for both minerals and energy more about this under the theme "Vent base alpha"



-- Edited by admin on Friday 15th of August 2014 12:27:07 AM

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