Pedal Boat Design

Oops. Never mind that.

The analytical machinery in my head isn't keeping up with the inspiration, lol.

 

Now quoting himself...I love it =)

Also, I just decided NONE of us are aloud to say things like "It would be easy" or "Simple linkage" anymore lol.

 

Good idea!

 

Curtis
:idea:
Rick

 

Here is the mono (or trimaran maybe) version.

It's rick's basic hull (18' long, 10" beam) with the exception of the notch for the flywheel propulsion pod (FPP for the PPB so I can PMAO =) which is also in the deck. I will run my hull top flange inward to clean the lines up a tad (it doesn't HAVE to be ugly Rick =) The notch makes the hull watter tight.

The FPP has all the drive sprockets (main, inner wheel sides, and outer wheel sides) in one package. The hump on its back is for a CF axle tube that will transfer power out to the far ends of the wheels. Four screws on top and 2 per side hold the saddle in.

On the outer most sides of the FPP the outrigger floats will cut a thin low drag swash, the arrows are about where they would go.

50-55 lb boat. Maybe 60 with all the FPP mechanics. No idea where the water line is, or where the wheels would settle...Ricks favorite program speaks math, and hates me.

It may not be "sexy" but I bet it works well.

 

BG
Took me 2 minutes to get the PMAO. From what you have been saying maybe just smaller rather than off.

The boat needs some detail like knowing where it will sit in the water. The prop should work OK even if the blades are fully exposed on the top part of the cycle. It will lose efficiency but will not be like a normal prop aerating. This is like being on ice in a car when it happens. I do not see how you will get pedal power to it yet.

The idea of it blended to the hull is good. It may actually be possible to have a three-part boat for easy transport and storage if they are issues for you.

I would like to see proof of concept with the wheel before getting into a lot more detail on the layout. For example I think the sides of the FPP will need to sit a little lower than the hull. However it may be possible to use smaller blades on a smaller wheel and spin it faster. These will be refinements of the theme as the boat comes together.

All the ingredients there for this to outperform the paddlewheel cat by a big margin but there is a lot to work through.

Are you still planning on a test tank of the wheel and paddlewheel? This basic layout also works for the paddlewheel just that the latter is much messier.

Are you able to do an animation in SW? Even seeing that will improve understanding.

This is at the stage where I normally head to the garage and do a basic model to test in a tub. No point going into detail if there is a fundamental weakness.

The attached is the geared foil I tested. My concept looked good and I partially anticipated the fatal problem of the high torque variation but in practice it was far worse than I expected. I phased the torque peakes to occur away from the deadspots on the crank. I managed about 5kph with this with a good measure of effort - so an absolute dog.

Rick W

 

(Sigh) I'd love to be better at this sort of thing, but I :idea: that I should stay within my limitations and do what I'm good at -- which is limited more toward things with no moving parts.

 

Curtis
My implication was that you had seen the light. It saved me going into the reason it would not work as you originally intended.

I have been fiddling with this stuff for 6 years now and it still takes thinking about.

I am sure if BG can build a working model it will be a lot clearer. It will also help identify unthought of impediments.

That fact that Voith have a commercial prop holds good prospects though. Also my calculations will be close providing the foils track the required path.

I have already thought of one issue with the side mounted wheels and that is they better have net lift otherwise they will make the boat roll.

I am off to bed now. You can take over the shift. I will look forward to the results in the morning. I think BG is slacking and actually gone to bed today. Must have good stamina for the speed he produces designs and the time he puts in. Hope the effort is worth it.

Rick

 

Yep. I pre-empted your correction, which seems to be happening more, lately. I'm better off taking the hint, which is that I've reached my ceiling. It's better for me to go look for a stairwell than bang my head. :!:

While we're waiting for BG's next progress report, here's a few pictures of the only boat I ever designed; this is a quarter-scale model. I designed this for my own limitations and requirements; power from kayak paddle, take-apart construction to carry, ten-foot length to fit in my pickup.
The rolls of coins represent my weight, to scale, and the one photo shows the boarding condition, where I would be sitting on the front of the deck. I was pleased that the model verified my calculations accurately. The last picture shows a second set of pontoons I made, with much speedier shape; again, this is the boarding condition. Pretty, but not practical for this design.

 

Slacking off? HA. More like the wife finally figured out where I have been hiding lol. Posted up those last images at something like 5:30 AM and then while staring at the drawings FELL ASLEEP in my chair lol. Awoke with Rick telling me that the superstructure needed to be an A frame for a more rigid structure, or some such. Obviously I just continued thinking about it while asleep lol.

Yes, I like the idea of the wheels flushed into the sides as well. Just no way for me to determine where the water line would be beyond doing a cross section in SW and then having it tell me how many cu ft the slice is. To ge the boat/wheel further into the water the only thing I can think of is to go with a smaller beam. Not a problem normally, but I am worried the boat will be quite tippy then.

I may not be able to have the wheels completely tucked in =(

That model is too cool Curtis. Balsa and obechi? Have to build one and take it over to my buddy Rick's pool (a local Rick). .25" x 5" x .0625" articulating three bladed wheels...now THERES a bit of sport lol.

 

Riding too high is a dead giveaway that inadequate cast iron has been used in fabricating components.

 

BG,
Glad you like the model. No balsa, just plywood, and faux-glassed foam pontoons on the first one.

The deck/seat assembly would be half-inch ply at full size.

The foam pontoons were built after Gary Dierking's Quick-Ama instructions;

http://homepages.paradise.net.nz/garyd/quikama.html

there's a central ply web with rigid insulation foam on both sides. You can see I copied his crossbeam attachments. I wanted to emulate a glass-epoxy coating, so I used a very thin cotton cloth and plastered epoxy on; it's very rough and ugly up close, but came very close to my calculations.

The plywood for the hulls would be quarter-inch in full size, and even with the monstrous overbuilding shown (upside-down, without stringers or skin) was still much lighter than the foam job.

There was a method to my madness in making it this way. All the pieces fit together with keys and slots. Notice that there is no glue on it as shown, but it's all straight and square. If the parts are all nicely cut, the assembly squares and straightens itself without forms or clamps. I figured that I'd be working solo on this, and hobbling around with a cane and trying to manhandle long pieces into place and clamp them would be too much for me. So, this.

Yeah, it'll survive a level of disaster that would certainly kill the pilot. I showed it to my brother, and he said, "That's way overbuilt!" I posted pics to the Yahoo Boatdesign group, and they said the same thing. If I were to actually attempt this in full scale, I would narrow the webs and eliminate most of them, but I like safety, so I'd keep the solid bulkheads.

As I was building these, I thought they were too flexible, even with the stringers, but once I put the skin on, I figured out that I could stretch strings on them and play music if I wanted to.

 

Oh, and another thing -- notice that I stayed within my mathematical abilities with the design -- it's all straight lines and arcs of circles.

Nice you finally got some sleep, BG.

 

Now your talking motorcycles..? Harleys.....?