Pedal Boat Design

Yup, and this would be easy enough to do with your design. The old school paddle wheels were compromises - they had to operate when the boat was both fully loaded and when empty. If it ain't helping push, it shouldn't be getting wet.

Y'mean something like this? http://cgi.ebay.com/Digital-Hanging...yZ384QQcmdZViewItemQQ_trksidZp1742.m153.l1262 That's a very generous offer - I wish I could help. Optimizing this old technology is fascinating.

I'm also quite grateful for these discussions and for Rick's patience with those of us who are arithmetically challenged.

Just the opposite, no?

 

LOL! Great! Now I have to go redraw mine.

 

Thanks Rick, perfect timing =)

Any idea what the second (aft most) little circle is? The dashed line is pedal arc I think right?

 

Curtis--

I am tinkering with the spokes idea. will post anything worth while.

 

Alexelbrite--

Shame those are so sluggish cause the do LOOK like they would be fun lol.

 

Tinhorn--

Wow...digital even. I was thinking some sort of old school calibrated springs and like a graphing arm that makes a mark on PAPER lol. Heck yeah though if Rick says that is acceptable pulling side ways instead of up and down I will get one. Reads Kilos too for Rick =). Resolutions only .5 pounds though, not sure how fine our numbers would need to be.

Even be handy for weighing finished boats =) or me after Thanksgiving dinner lol.

 

Rick--

How confident are you in that seating position in regards to the feet height? If I read it correctly and the dashed circle is pedal arc it looks like that setup would put the legs/feet higher then the the riders heart. From what I have read that is a bad thing....

 

Found the International Encyclopedia of Ergonomics and Human Factors Which has some interesting information.

http://books.google.com/books?id=fd...X&oi=book_result&resnum=9&ct=result#PPA505,M1

It also says that having the feet above the heart leads to "sleepy legs" so I think I will go a bit lower then the diagram you posted Rick.

Anyone else have any good sources for this type of info?

 

This set up is for a low seating position for 4 pedallers gang to a single longitudinal prop shaft. The second circle is the sprocket for a right angle drive. These boxes would have 15mm through shafts capable of taking the combined torque. The boat was intended for a 15 minute race.

Rick W

 

It is sleepy feet. It is particularly noticeable in cold weather.

You have to be a little careful with the things stated in some of these texts because they are for well-trained athletes. For example I prefer to have my clips closer to the instep to reduce load on the calf muscle. Not optimum but something I give away to make it less tiring on a part of the body.

I know a fellow who uses 125mm cranks and spins comfortable at 140rpm. So there can be lots of variation to suit individuals.

I go for the low seating position on my monos for stability reasons. On my cat I set the pedals lower.

The swing arm system I used on V12 gets CofG lowest without feet being above the heart. It is the best position I have tried - very natural.

 

Oh, thats right Rick, sleepy legs happen when you sit on the throne too long...I always get those two confused =)

 

By the way the seating diagram was one I did for a fellow a while ago. It is close to what I use but my back angle is much lower.

Sleepy feet is an issue for me and others who use low recumbent position. I wear socks in winter. It helps dry the feet as I operate from the beach normally as well as providing a bit more insulation. I find wiggling the toes overcomes it but it requires attention. I do not notice it in warm weather though and I have had continuous stints up to 9 hours. I posted the attached photo on the pedal boat thread. It was for the steering windlass but it also shows the seat back angle. It is surprisingly natural for me. I could just as easily be at home on the couch watching TV but the boat is much more fun.

Keeping low reduces windage and helps ballance on a monohull. If you sit high on a narrow hull it tends to flop onto the stabilisers. Sitting low allows you to achieve ballance once moving.

Your objectives are somewhat different to mine. I love my cat as a development boat but it is just too heavy and relatively slow for regular use. Nothing like a boat you can pick up in one hand. Greg K has got his V11 copy down below 18kg. Not bad for a 24ft pedal powered boat with stabilisers. My newest boat is 23kg.

Rick W.

 

Yeah, I would be the same way I think. I am at my desk 14+ hours a day and I put my legs up with calves on the desk (usually crossed ankles) with my chair leaned WAY back and the keyboard in my lap. Puts my head/neck at a sharp angle yet I have no problem. Wife thinks it's weird that I can hold my neck at that angle no problem. Anyway, my feet don't fall asleep either.

I cut my building teeth on high performance sea and float planes so I have no doubt I could build an extremely light boat. That said I am also pretty familiar with hangar rash. For a once a weekend boat thats hauled 30 minutes and beach launched, then ridden hard 7-8 hours and hauled home, and will usually have at least one 50 pound dog on board as navigator...60kg would be fine. Even 65kg as it is a tandem boat and has paddle wheels.

I know I harp on looks a lot but if you have ever watched or been in a Cub or older 172 on Edo's when it comes up on the step then breaks free...just has a beauty all it's own. Neither plane is remarkable in speed or range. Same with a Catalina or a beautiful sail boat. Call it personality. I am betting Tinhorn feels the same way when he sees an old stern driven River Queen.

One thing I have taken away from your experiences is that it's still a process and theres never just the one boat lol. Use this one for the summer, build the next one over the winter adding what we learned.

I have been working on the frame this evening. Your going to hate it too but I'll post some pictures later anyway =)

 

People find different ways to occupy their mind. I used to be an avid sailor but my kids did not enjoy it the way I did. I only had them ploughing through green water a few times (not really). It is just that kids have a different concept of time. Ultimately it was a selfish pastime and priorities changed as they got into organised sport. The eldest did try sailing and was good at it but it separated him from friends.

I could have golf club membership and pay my green fees every weekend but instead I order some more glass and epoxy and have a bit of fun in the garage and then test the results.

Pedal boating is something that can be enjoyed on the weekend before the rest of the world gets out of bed. If things are nicely set up; just put the boat on the car, 10 minute drive to the lake, pop the boat in the water and away you go. One thing that I have discovered is the significance of boat weight in getting the boat to water and especially back home after a long ride. If you do not have this well organised you can impose a lot of angst on the exercise. If the boat is a bit heavy you need well-drilled company or a neat trailer.

For me the ease to get to and from the water is a priority. I can get in 10km on a Sunday morning before the rest of the family are out of bed. I can do 4 laps of the lake before the sailing boats are rigged.

I appreciate form and function but for me the latter comes first. On the other hand I value the skill some people have to combine form and function in an elegant way.

With my early boats I would always get the question - did you build that yourself? Now I sometimes get the question - man where did you buy that. But my boats still do not pass the close-up test. I am simply too impatient and always developing new techniques. I can build in sheet aluminum fast and it looks OK. A full-size hull takes about 10 hours now. Quicker than the first pot of epoxy sets in our current cold weather.

 

Amazing the things kids decide not to enjoy isn't it? My mentor in my early 20's was an engineer with NASA's Jet propulsion labs and an avid R/C modeler in his free time. Lived right on a lake and also built boats. Both his children didn't care for either boats or airplanes. I swept up his shop just to be near all that cool stuff and learn what I could.

I whole heartedly agree that if it's hard to get the boat from the garage into the water people are less likely to use it. We have quite a few boat launches scattered about the bay here and I can build a trailer in a weekend. Just not sure about trailering something that light lol. Could easily pull it with the wifes convertible...if there was a way to get a hitch on it and the wife would let me lol.

I will keep at it trying to cut out the fat. I don't suppose you know how many layers of CF or a final thickness for a quality hull by any chance?