River Roller! Pontoon Boat that Rolls Across the Water!

Looking at your original claim though, I understood from your drawing that you would not have any planing surface on your boat. Ie you would be able to get your boat "on step" or on top of the water at high speed. I believe that at least one of the contributors suggested that you might need a planing surface to get the thing going. No one has denied that a paddle wheel will provide forward force. This mode of propulsion has been around since the early 1800's

For me the unproven claim is that you can get this boat moving at high speed in the configuration without a planing surface.

Both of these writings have the model starting out at rest on a buoyant platform then applying power, getting up to speed and in one case at least, the planing portion becoming clear of the water.

 

the challenge with this design is how to effectively get between the only two useable speeds of slow idle paddling and wide open throttle to skip across the surface.
in order to overcome the dead zone where it digs a hole into the water why not add a quadcopter top to it... you could take off just above the surface and accelerate till its at max speed and then cut the rotors and Floor it with the trantoons..... and as a added bonus be able to use the rotors at low voltage as ceiling fans when at rest or when slow idling on hot days.... could even have them tiltable to help generate electricity and recharge the batteries when not being used to get the vehicle to top speed.

 

Well if there was an exact example of the River Roller this would all truly be useless. The one craft shows a clear proof of concept of riding on the paddles tips at high speeds. I think that the interior of the paddlewheel will intefere little with the abilitiy to skim across the water. So there is some proof of concept here for high speed function.

The other shows the ability to achieve high speeds and minimize the spray. Minimizing the interaction between trantoons will be key to efficiency. So some more proof of concept there also.

I've been meaning to come back to your previous post and try to understand it better. I don't suppose you have a graphic for this?

 

Yes there is not a complete proof of concept on these papers. Just additional positive evidence for proof of concept.

 

Nice! Best post so far! To the point and funny! Yes the transition is of concern to me. I figure the transition will be simple when the trantoons aren't submerged too much. It will be a greater and greater challenge the deeper the trantoons are sitting in the water at stop. At some point they will be so deeply submerged that It will prove everyone here right and It will never "Plane" out.

 

glad I could bring some humor.

in all seriousness maybe try just putting the paddles on the outside edges of the toons.. at least that way it shouldn't immediately sink due to cavitation directly under the main mass of the boat on take off.... then again it might just as well make a hole on either side to fall in and crash on the way to full speed.

 

Cavitation or ventilation, which do you mean, do you know?

 

Sorry for my flippant use of terms on what was originally intended as just a pithy and flippant series of replys to the OP... to answer your question it will primarily be a problem of ventilation with the paddles shoveling air under the boat as fast as they can but with the massive amounts of force required to do what he is proposing im sure some cavitation of any water lucky enough to displace that air will occur as well ... guess ill just stick to the highly technical term " blowin a'hole in da water"

 

Proof of progress. This is a first mock up of frame and trantoons. I'm having some wobble issues. No biggy but slowing me down.

 

Ok, you all see that digging a hole is entirely weight dependent right? If the Roller is light enough it will just skip across the water no problem.
The heavier it gets the harder it will be to get out of the hole. Just like any other boat. I'm sure that heavier loads can be accommodated by simply transferring power to the most effective trantoons. Remember each trantoon is independently powered. So some trantoons will have different rpms to maximize buoayancy while others will focus on traction. While this equation is currently unknown it should be doable.

 

I will ask again, what is a reasonable plane speed for a 1/12 scale model? Please let me know so i have a goal for my Model. Surely someone out there can quickly tell me this answer.

All assistance is appreciated.

 

The speed is determined by the exact hull design, and you don't have a planing hull, so how can that be answered.

It is nice to see progress on the scale model.

 

For surface vessels speed scales as the square root of the physical dimensions. So the speed of a 1/12 scale model would be equivalent to a full size vessel going 3.46 times the speed of the model. A 1/12 model going 5 knots would be equivalent to a full size vessel of the same design going 17.3 knots.

 

Interesting
And how do you account then for weight?
Ie 1/12 the weight, as you have 1/12 the wetted surface etc?

or?

Re the "speed scales as the square root of the Length?" Do you have some reference for this? I would like to read a bit about it

 

Barry asked about weight and the other thing would be, how do you scale the propulsion power needed up or down? If a full size boat took 100 hp, how much would a 1/12 model need?