October 10, 2006


Thinking WAY outside the box! - The human powered submarine

I've been getting some really great emails from you all regarding my previous semi-submersible concept, so I thought I would keep this 'thought-experiment' rolling, by GOING ALL THE WAY - the full-on human powered submarine.

This is a cool idea, but really way too dangerous for an ocean crossing. Too much can go wrong, and some of those go-wrongs could kill me. But, for fun and adventure, I can't imagine a better way to travel through water! Being well below the surface of the water would completely remove any ill-effects of weather and rough ocean conditions. It's always a beautiful day 10 feet below the ocean surface!

I wonder how tough it would be to build something like this...

Rich Easton tells me that he Mormons believe that a prehistoric East-West Atlantic crossing was made by a submarine. And some of you also pointed me to the Hunley which was a civil war human powered sub!

Human Powered Submarine (click to enlarge the images)

I started with a revolved NACA laminar flow airfoil for the main submarine body, and adjusted the seat position such that my head was just above the main sub body. The fore-aft position of the seat with the weight of the ballast keel below the prop is set to balance the vessel front-back. To minimize the volume of the air filled cockpit area, I placed a small dome over my head, which could also serve as the entry/exit conning tower.

To further minimize the air volume of the cockpit, the chamber wall dividing the stern compartment from the cockpit could take the shape of the back of the seat. Same for the front wall dividing the bow compartment.


(click to enlarge)

There would be a fresh-air intake valve at the top of the rear fin. This should be something that would allow air to flow in, and not water. The top of the rear fin should stay above the water line, but according to some reading I did on the Hunley, the crew were able to dive far below the water line for up to 2 hours after fresh air filled the cockpit from the surface. So it may be possible to dive lower than what the top of the fin would allow for.

The sub is divided into 3 air-tight compartments. A hand or leg (pedals) pump is used to pump water into the bow and stern compartments to decrease buoyancy. Another pump can be used to vent the water ballast out of the bow and stern compartments by pumping air into them from the fresh air intake on top of the rear fin.

A weighted ballast keel below the prop is used to keep the human powered sub upright.

Small wings on each side of the human powered submarine could be used to make small adjustments to it's depth when moving forward rather than replying solely on the amount of water ballast. I didn't draw the wings. Ah, I couldn't resist - here is a rendering with the wings:

Actually, now that I look at it, I think it might be smarter to make the ballast keel a mono-wing. The angle of attack could rotate providing lift or negative lift.

And here are some other cool shots of the HPsub:

I don't know much about submarines, but it would seem to me that the bow and stern compartments when filled with water would weight the SAME as the surrounding water, and therefore will do nothing to help submerge the sub. Therefore, the weight on the end of the keel below the prop has to be heavy enough to negate the buoyancy of the air-filled cockpit. I'm not sure how heavy that would need to be, or if there is some other way to decrease buoyancy aside from water and lead.

One idea is to make the sub slightly positively buoyant and diving is accomplished with wings which force the sub down under the water when moving forward. This isn't a bad idea, as it wouldn't require any pumps or filling compartments with air or water, etc. However, some component of power required to move the vessel forward would be diverted to keeping it under the water - a trade-off. How much I don't know..

Pros:

1. Erase the adverse effect of waves and wind and weather slowing forward progress.

2. Stability and comfort. Under the waves and under the weather makes for SMOOTH sailing

3. Because it would be the coolest thing ever!

Cons:

1. If something sprang a leak, or malfunctioned, it could be game over batman.

2. Heat. I think it could get pretty hot in there.

3. It would be hard to build strong enough to withstand the water pressure. But then again, it's not meant to dive any deeper than 5 to 10 feet...

I don't know.. What do you think? Is there a way to design this thing so that if everything broke, it would not sink? That would be the key to building something safe enough to use.


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