Split Paddle Wheel propulsion design

More than good reason.
Believe me, if the crackpots and MacGyver's of the industrial revolution era could have done it they would.
Right along with the flapping fish tails and, (later on,) ornithopters.

 

I have been running a sidewheel steamer for more than a decade, and have a couple other steamboats as well as IC boats. See youtube video: <<< >>> . If you want to build mechanical complexity, consider a steam plant. Most of the parts can be cobbled together from IC engine parts, plus plenty of welding to make a boiler.

For a displacement type hull at "hull speed", two or three horsepower per ton of displacement is sufficient, even considering the lower efficiency of paddle propulsion. Displacement hull speed is: Speed (knots) = 1.34 x squareroot of waterline length (feet). This gives about 6 knots, and a maximum of 10 horsepower will push a 4 - 5 ton boat.

On the other side of performance, various snowmobiles can actually go faster than the high performance personal watercraft. Functionally these snowmobiles are actually using a propulsion system that is the same as a stern paddlewheel boat. A traditional stern paddler could be built with similar high performance. You could build a fast sternwheeler if you want, with a few hundred horsepower for a 30 foot hull. Automotive engines and drive train components can be adapted to this path.

I have been educated in paddlewheel propulsion, and am willing to assist you in design details if you like, once you decide on the basic direction you would like to take: Steam or Internal Combustion power plant, fast or slow, traditional silent or viscous radical fast. Have a look at the Beckersville Steam Engineering Co. website.

Photo of articulating paddlewheels built for my sidewheeler.

 

But what a spectacular failure it could be! Fun to watch. If those aviation pioneers had the movie rights they would probably be rich men.

 

You've given me plenty to consider. I'll respond more later. Thanks.

 

The commentator in post 12 offers misleading information wrt to choosing power.
His comment that Torque is the predominate factor when choosing an engine and Horsepower does not really matter. This is incorrect.

Torque is measured as a static twist in a shaft. For discussion purposes say it is 1oo pounds feet . If you maintain this torque in a shaft while it turns at
say 100 rpm, it produces X Horsepower. If you maintain this torque in the shaft while it turns at 200 rpm, it produces 2X horsepower.
( by saying that "you maintain this torque" I mean that the load/resistance to twist is increased as it is this load that creates the demand for the HP requirements)


Horsepower is Force through Distance with respect to Time.
If it takes 50 Hp to push your boat through the water ( Force component) at the speed (Distance and Time component) that you wish to drive it at; irrespective of drive mechanism losses, paddle wheel efficiencies and hull drag, you need a engine that produces 50hp

That does not mean that you pick a 50HP engine. As a 50 hp engine would be then running at an extremely high RPM and will not be fuel efficient.

 

I'm sure that most everybody on this forum understands the relationship between Hp and torque.
Neither the commentator in the video or we on this forum have any need to be pedantic, driving down endless rabbit holes that don't lead to anyplace worthwhile.
Theoretically you could turn a paddlewheel with a leaf blower engine if you had enough gear reduction to provide the necessary torque, but the gear reduction necessary to go from many thousands of rpm to ~60 rpm would absorb most of the power you started out with.
I believe that the guy was only trying to make the point that having an engine with high torque at low rpms enables a more efficient propulsive system without having to use massive amounts of reduction gearing.
In that respect he is totally right.
The old hot rod saying, "There's no replacement for displacement" is quite true for paddlewheel drive.

 

I will need to sit down and get an estimate of how much hp it would take to move a through the water with a paddle wheel. Actual hp needed isn't critical at this point. I can install whatever hp I eventually need. No more than 10' wide no more than 25-30' long. It needs to be trailerable and it needs to fit through my smallest shop door. Try to keep the weight under 10,000 lbs.
At this point I am most focused with what it is going to take. Engine(s), transmission(s), gearboxes, shafts, etc. And the layout of these pieces. Aesthetics and functionality both matter.
The only absolutes at this point are: Not steam powered, not side wheel and not noisy.
At this point I am still leaning towards the split rear wheel. To the argument of it isn't worth the effort. Worth is relative. I guess my question would be is a split wheel hurting anything? More hardware to break but also some redundancy. I'd lose some wheel width by splitting it in half.
I kind of like the one engine powering 2 transmissions option. One cool looking big old engine. More open real estate.
2 engines w/ attached transmissions like an Atomic 4 for example. Fairly compact package. Total control of individual wheels.
I appreciate all of the input even if I don't respond directly. All the information is good. Just need to find the time to watch videos and do my reading. Thanks.

 

That goes against all properly recorded data. If paddle wheels were better, tugs would use them. They are inefficient and prone to breaking and fouling.

 

That would be a modern engine with a well designed and matched muffler

A big old engine will no be smooth and quiet as you want. Atomic 4 engines are not very efficient. Further, you would have to add a second transmission with a reduction gear to go from 2800 RPM to 80 RPM, which is a 35:1 ratio. You can either have a very large gear or a series of reductions. Open crankshafts and gears, like some suggest, need to have a protection cage or most likely people will get injured or killed, particularly in a small boat.

 

Probably most contributors do but in general the average person does not.

A 50 cc leafblower will produce betwen 3 to 9 hp. Assuming that Theoretically you could turn a paddle wheel with a leaf blower engine if you had enough gear reduction it would not turn
the paddle wheel at 60 rpm if the boat requires 50 hp to the paddle shaft.

My point of taking his comments to task were simple. It is not torque that will drive boat but HP. You gear reduce to increase the torque but the HP is the decisive factor.

The OP will be at some point be trying to determine how many HP to put behind his build. The commentator said that he has a 105hp 4BT diesel.

Horsepower of a 50 cc leaf blower engine
Displacement(cc) 49.5
· Rated power output and Rotational Speed (HP/RPM) 2.8/7500
· Max. Power output and Corresponding Rotational speed(HP/RPM) 3.35/8000

 

A steerable paddlewheel sounds like a terrible idea! I’m picturing an articulating paddle wheel at the stern which would require a substantial keel under the hull, usually a bad idea on a shallow draft barge type hull.
Maximum maneuverability means spreading the wheels as far apart as is practical.
Moving side wheels towards mid ships should cause it to turn on a dime, and possibly operate without any rudders.

 

You might want to talk to the operators of the riverboats in Taylors Falls MN about dual stern wheels and maneuverability. They may operate the only class I - II whitewater paddle wheel tour boats in the world. The captain said that paddle boat captains from other places can get a bit panicky going around one of the islands. The river can be crawling with clueless canoeists on weekends, so they have to have good control over the boat. It's a 4 1/2 hour drive.

Visual complexity is good for getting attention. Mechanical simplicity keeps you clear of the rocks. Drive the eyewash with a chain off the wheel axle and drive the axle with hydraulics.

Complexity can be used to some degree of advantage, such as feathering paddle wheels. The website below has a lot of paddle wheel stuff.

Paddleducks - Feathering paddlewheel. http://www.paddleducks.co.uk/smf/index.php?PHPSESSID=d01994555ac3a4699413187745c8911a;action=gallery;sa=view;id=4144

This page, if you scroll down far enough has a sideways fully submerged paddle wheel, but the page heading is of more interest in some respects.

 

My original question had to do with having a split rear wheel on a paddle wheeler. I want to thank the people that provided info to that question.
I didn't provide any of my history. Maybe I should have. I have fabricated and built stuff all my life. Sailcars, hovercraft, boats, cars. With the exception of the sailcar( I was 10 years old) everything has been engines, hydraulics and gears. I know about heat, noise, safety, etc. I understand hp and torque. I know not everybody does.
I don't need to see the experts bickering.
So with that said, I am done.

 

Promises, promises...

No pictures, no plans, no progress?

You're welcome.

 

Thank you for this info. It is very on point. So, in response to my original, a split rear wheel makes a difference.. You sent this when I was typing up my resignation. Project is still on.