Pedal Powered Boats

Hi there

I have managed to acquire 2x1 gearbox like the one pictured. I really like the simplicity of attaching the crank arms directly to the gearbox. I have the parts in front of me and it looks easy enough to put together.

However, I am aware that 2x1 isnt a very high ratio at the prop. I was looking to do a 6x1 ratio using bike gears like Rick W.

I am not building a record breaking boat and more of an expedition boat.

can I make up for the slower prop speed with a larger/higher pitch prop? Is this a massive impediment to performance? Does anyone know what the builder from the pic did?

The openwaterbike website is down which is a shame as it had useful info. Seems like a lot of of the pedal boat info is being lost from the internet.

 

As with many expired websites, you can find various old versions of openwaterbike.com at archive.org. I have no idea how much of the content they captured. Waterbikes aren't my thing, but you can look for yourself.

Perhaps someone here knows if the full archives are available online.

 

yes I have briefly checked that out, but only found old versions of the site with less pages. I will probably do a more in-depth search. It’s difficult to even find old websites these days using google, they are buried deep in the search results.

 

Well, if you're a big guy, you could put longer crank arms on.
A larger prop would certainly be in order, perhaps up to 24" x 24".

What's your total/loaded boat weight and design?

 

You can work out your maximum speed potential from the pitch of your prop. A 24" for instance with your 2:1 gearbox would, at a cycling cadence of 90 rpm, give 72" per second. Of course you will always have some slippage from the prop. so I'd think that 4 mph would be the best you could expect. This may well be acceptable or you could add a chain and sprockets to improve the speed. My own pedal powered dinghy could reach 4 mph with an energetic cruising speed of 3 mph. I've sold it to build a new pedal powered catamaran. The excitement is palpable.

 

Don’t think I can get away with longer cranks, I’m already using 175mm in recumbent position.

24” sounds like a really big prop, feel like there will be problems spinning a prop that big. Is there a point where increasing the pitch isn’t enough and the length has to be increased. As you can probably tell I don’t know alot about prop design.

I don’t have a design yet, I’m just wondering what is possible. 4mph would seem a reasonable speed, obviously it depends on the craft.

 

how does 4mph feel like? Does it feel like good progress, or is it a bit of a drag compared to paddling?

do you have any plans for your new boat? Are you still going to use a paddle wheel?

 

Perhaps someone here knows if the full archives are available online.

Don't give up too soon.

The project manager's info is at from the Project Manager – OpenWaterbike Project https://web.archive.org/web/20210916235557/https://openwaterbike.com/projects/open-waterbike-propulsion-system/the-project-manager

which in part contains

I don't know whether clicking on "please contact the project manager" goes back to the non-working openwaterbike.com site.

If so, searching for +"Apollo Yann Sande" finds links like

P2PU | apollosande https://courses.p2pu.org/es/apollosande/

who is in Nairobi, and gives a number of ways of reaching that person.

There are also finds for +"Apollo Sande""

Good luck.

 

My dinghy had a flat transom which caused some drag. My new design is a catamaran with a fine stern as well as bow so should drag less. Even with the dinghy I was faster than an inflatable kayak but slower than a hard shell version. I basically travelled at walking pace so if that's fast enough for then 4mph will seem fine. Remember that any dinghy will need to plane to go much quicker than 5 mph and this is unlikely to happen under pedal power.

 

A maximum Speed of 4 mph for a one-man boat may or may not matter depending on what the goals are and where someone will be doing their boating. Consider a search under "Adventures of Greg" a trained athlete who holds the world record as of 2017 for 24-Hour sustained speed, of somewhat below 11 kpH or just above 6 mph, displacement craft, no foils, not planing AFAIK. The boat was a super efficient 13 lb carbon fiber shell designed with input from Rick Willoughby an engineer and hobbyist, was a former poster to this list. Short distance racing craft can have burst speeds above that, especially if hydrofoils are involved.

As for myself, I like reading about tiny one man boats, some of the world record holders are truly amazing! I use a tiny inflatable 5' customized e-powered boat up to 100 times per year, mostly on rivers, and with a range of 10 miles @ top speed of 3 mph, 25 lb fully loaded including tools, spare parts, powertrain and 1 liter of water. It does everything I want for me including air travel in a carry-on, but, of course- it might not work for everyone!

 

Props are all about disc area and pitch ratio. Generally, for efficient HPV props they are large, thin, and slow turning. I've designed a 36" counter-rotating set and 4 knots was an easy pedal.

 

Your boat sounds cool, do you have any pics of your drive and prop? I was planning on just using an off the shelf 16” apc prop, but if I go with a 2:1 drive I will need to find it make something bigger.

 

yeah I’m not really sure how speed relates to actually being on the water. I already kayak but I’ve not thought about how fast I am going. I overtake people on the tow path in my unsporty kayak, so I must be doing better than walking pace.

I feel that a pedal boat has to be at least as fast as a kayak to make the endeavour worthwhile. But with that said I’m sure with good ergonomics I could do more distance using my legs

 

This is exactly why I'm building a new boat, to get a better range at a similar speed. I am making my hulls rather short for storage and so that I can get the boat to the canal. I'd imagine with kayak length hulls I'd be faster than a kayak. After all legs give more power than arms. Paddles, however, are quite efficient whereas props may be less so.

 

The more detailed your statement of requirements SOR, the easier it will be to get suggestions.

I read only a couple of things so far, must be as fast as a kayak, and must use an existing 2:1 gearbox, though it's not clear how far up these are in your hierarchy of the SOR. A 16x16 prop is most likely incompatible with those two SOR things as they stand now, but a 24 x 24 prop might be workable, however it will cost you $$$ and time to find out, and you may not hit it right the first time.. Other considerations that might be good to know: your budget, your level of mechanical building skills, whether you will be using your existing kayak or something different, particular purpose of the boat ( leisure, fishing, racing against kayaks, exercise) etc.

Hope this helps.