River Roller! Pontoon Boat that Rolls Across the Water!

I don't see how it can truly plane in a tradtional sense.

Planing requires resistance of water against the planing surface.

In thid case the planing surface is moving aft and I don't see how that will use resistance to push the craft up out of the water.

I suspect if the combined bottom shape of the toons was replicated as a one piece corrugated surface it still wouldn't plane easily.

If the toons are successful I think they will work by slapping their way across the surface.

 

The

Planing is just supporting the hull from increased hydrostatic pressure rather than fluid displacement. The thing is - ANYTHING can plane given enough surface area and speed. Think of some of those rocks you have skipped on water.

BUT - rollers will probably just dig into the water due to their curved profile, unless they are rotating against the direction of travel

The power drain ( fuel consumption) and required engine weight to get to the required speed will probably be just too much when trying to Plane this contraption though.

 

Think you mean hydrodynamic pressure and not hydrostatic pressure. Still don't think planing can be applied to this thing.

 

The links to similar craft I put in my posts used planing surfaces to achieve their goals on the high speed end of things, some relied only on the planing surface to stay above water, others had planing hulls that supplied flotation, the paddles only provided propulsion.

In this thread some people have suggested using planing surfaces to aid the paddles, but the OP feels the paddles can do all the work.

I agree, I don't think you can call this a planing hull. And dragging a scale size model of this hull in the water would be meaningless, it needs to be under it's own power for a test to have any value.

 

" The Main Difference between both hydrodynamic fluid and hydrostatic fluid is that one is study of fluid in motion and the latter is study at rest resp."
Difference between Hydrostaics and Hydrodynamics | Aerodynamics | Fluid Dynamics https://www.scribd.com/doc/43645725/Difference-between-Hydrostaics-and-Hydrodynamics


When a boat is planing, the water is at rest. So I always assumed Planing is a function of HydroSTATIC pressure. If the craft was being supported by the movement of water eg fast flowing river current, then that would be HydroDynamic pressure, to my understanding.

 

You are absolutely correct that the water is at rest under a planing boat and much of my understanding of planing phenomena rests on that factoid. Nevertheless, at the interface of the hull bottom and the water, this is irrelevant and planing lift generated is dynamic and not static. Static lift requires that there be no relative motion between hull and water, i.e., the boat is at rest on the water.

Based on your comments you might like to read my own take on the theory of planing. Planing boat theory – Bluejacket Boats http://bluejacketboats.com/planing-boat-theory/

edited: As I read over this , I see that there is some possible confusion about the "static" water. I should have said that the water is static until set in motion by the passing boat hull. On contact with the inclined hull, the water is accelerated in a vector normal to the hull surface. Dynamic lift is thus produced in direct proportion to the force exerted on the water to accelerate it. This works in exactly the same way for rocks or golf balls or a boat bobbing in the waves from a passing boat. If motion is taking place, its dynamic and if there is no motion, its static..

 

When a boat is planing the water is not at rest, it is acted upon by the planing surface. Planing is dynamic, it cannot occur statically.

 

Lol on the shop vac! Thanx for the Ideas. I only really differ with not needing a motor for each trantoon. I think that is necessary to provide power to the most effective trantoons.

 

Yea. I was thinking bigger would be better. Thanx

 

Thanx! Good to hear.

 

No. I just wanted to get it into the water and see what happens. No proof of concept for this test.

 

Hello All,
Back from a long vacation on a chain of lakes in Wisconsin. I spent a fair amount of time and money on gasoline and oil. Whatever you all think about my design, an solar charged electric pontoon boat seems like a winner. It would be great just to get in and go. Even on a partial charge the sun would be enough to just cruise around.

Some food for thought. I noticed that my when my kids tried to get away from me in the paddle boat, pedaling faster seemed to reduce the effectiveness. Clearly trantoon speed will have to be relative to water speed.

Its amazing the difference a vacation can make in terms of objectivity. I have a few design changes in mind. I'll post them as soon as I have refined them a bit.

 

Well, I admit to getting tired of the ******** and jumping to the end of this, so if someone else made my points here previously, I apologize.

First off, stop talking about planning. You are not designing a boat that runs in the water. You are designing a vehicle that runs on top of the water. If you have the buoyancy where your roller run only 10%25% sub merged you are basically walking on top of the water not running in it. The hydrodynamics are not the same at all.

I doubt the solar electric is going to work in the real world. It just does not. As a supplemental power supply, it has possibilities, but not as a primary.

I also doubt the speeds you are talking about. There are amphibious ATV's, they do not have the floatation you are talking about so have hulls, but they are slow on land and slower in the water. There is actually a high floatation tire called an Aquatrack or something like that that is designed to use on them.

Your vehicle would be a skid steer vehicle like a bulldozer or a military tank, changing the speed of opposite rollers.

Another problem is that you will not have the grip on the water that such a vehicle would on land.

I am not interested enough to try and do the math to prove or disprove the possibility of such a vehicle but would give it a strong maybe.

 

Wow. One of the most sensible replies so far. I appreciate your time and hope you will take some more to respond further. I guess I've been using the word planing loosely. I figure there are 2 modes of operation. First is "Light" mode. Where submersion of the trantoons are minimal. Second is "Heavy" mode where submersion of the trantoons is significant. Light mode should be simple and tread across the water easily. Getting Heavy mode out of the water to the point of "Planing" will be the challenge.

I've use the phrase "Solar Charged" many times here. The idea is that a boat sits doing nothing in the sun more than enough to accomodate the occasionaly day of fun in the sun. Range anxiety, normaly associated with electric cars, can easily be accomodated by the ability of the sun to slowly return the craft to the dock.

I appreciate the acknowledgement that conventional hydrodynamics do no apply here.

The grip in the water will simply be a function of the design and use of the trantoons. I'm confident this can be engineered.

Speed is definitely up for debate. From what I've seen the water buggys are capable of significant speed with just four limited wheels providing propulsion.

Thanx for the strong maybe. I don't suppose I can convince you to actually vote yes? I could really use the support.

 

I haven't read this whole thread, so please excuse me if some one else has posted this. I think what your proposing would operate in the water very much like the Sherp in the linked video with out the advantage of the Sherps large diameter tires to provide paddle speed.