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      Abbreviated rules   07/28/2017

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Russell Brown

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About Russell Brown

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  • Location
    Port Townsend WA
  • Interests
    Sailing, boat design/development.

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  1. Sailors Powerboat

    I'm not using this boat much anymore, Jim C. It could be yours. Oh Hell, you live in England.
  2. Sailors Powerboat

    I got to use this boat for a cruise with my wife and friends Steve & Kathy Callahan. I'm not the world's most experienced powerboat guy, but it seemed to do everything amazingly well. It had a big-boat feel, went plenty fast with 60 HP, and handled a long stretch of punching into really nasty chop with good speed and without stress. I think that people who commission and own fuel efficient powerboats are doing much more for the environment than just saving fuel. They are showing that it doesn't take horsepower to be cool. The opposite maybe... I also really like the motor yacht that Bob Perry has been working on. Imagine pulling into a marina full of Bayliners and Sun Seekers with something like that.
  3. R2AK 2018

    My comment about pedal drives being for sissies was a bad attempt at self deprecating humor. It's not a surprise however that the world expert on pedal drives for boats is from the Land Down Under. I guess we have as many cyclists here as anywhere, it's just that we have more monster trucks and mega yachts than anywhere else. Rick, I'll work on the geometry drawing. I don't do CAD, so need to talk Brandon into helping me. Most of it is there, just need to insert the new pylon geometry.
  4. R2AK 2018

    It takes me a couple of reads to fully understand what you are describing, but I get it. To use a double universal joint, the thrust has to be taken by a thrust bearing on the strut. It appears that you have been down all these roads. The sideways folding strut really doesn't work because the boat is so narrow. If I used the stiff/flexible shaft drive, I can get the lower sprocket/universal joint down to about 250mm above the waterline (with a fairing in front of it). If the shaft was 3 meters long and half of it was a stiff tube, the stiff part could end about 75 mm below the waterline to put the prop well underwater (but square to the waterline). The universal joint would take about 12 degrees of deflection at this level of immersion according to my drawing. Would this amount of deflection take a double universal joint? All inputs about universal joints welcome! If I used the stiff/flexible shaft, it could be quite a bit longer than 3 meters to make the angles better and I have 3 potential strut locations along the length for supporting such a long shaft and for installing a thrust bearing if I need to use a double universal joint. I have bought SS universal joints from McMaster-carr that seem good. Expensive yes. I have learned a lot from you already, Rick. I can send you some $ when we get this all figured out, or I can return the favor in some other way possibly. I think it's good to keep this discussion public as we don't know much about this stuff over here. Monster trucks and mega yachts are the way here. Pedal drives for boats are for sissies...
  5. R2AK 2018

    Rick, this is a lot of information that you have shared. I have been all over the map in my head and in sketches with this pedal drive thing. That I managed to build a successful one for the last race in a few weeks just before the race now seems kind of unlikely. Facing sideways was what allowed my last unit to be so simple and efficient, but it really doesn't help much with my new quest for a unit that can be deployed quickly. Having the leg fold sideways is not very attractive because I have low underwing clearance and the thought of hitting the folded leg with solid water at high speeds doesn't seem like a good idea I could see having the leg fold aft using the two separate belt system that you mentioned, but I would need a third belt to joint the two at cockpit floor level. I can picture how all this could work, but is it a good idea? I don't know. I was attracted to the bent shaft thing because it is only two sprockets, one chain, a universal joint, and a long shaft with a prop at the end of it. It's simple, and it fits the geometry of my boat. I want to ask if you can see a way that it could work. Maybe a stiff carbon shaft for the front half and a flexible shaft aft? Would you be willing to help me as a client, instead of just giving me free advice? That seems more reasonable to me. That way I may have a chance of having the system work the first time. I can provide a CAD drawing of the geometry of the boat including the proposed pedal pylon, etc. Russell
  6. Anyone know this cat?

    Tell us what you know!
  7. R2AK 2018

    Okay, you have given me a lot to think about. Would the uneven loading on the prop caused by the inclined shaft be the same at 3 knots as it would be at higher speeds? A folding leg is difficult on my boat where the pedal drive needs to be in the middle of the cockpit. There's not enough width to fold the leg sideways. Folding it aft might be possible, but I'd like to avoid using a gearbox. This short video shows my old pedal drive from above and below better than the other video: https://www.youtube.com/watch?v=BIW7kPpZwbU Thanks again, Rick, Russell
  8. R2AK 2018

    Thanks so much for responding, Rick and for offering your help. I had thought about using a carbon shaft as my shaft will have to be about 10 feet long, but a stainless shaft would be so much easier to make the bearing for the strut. I do have a relationship with a carbon tube manufacturer and could have a custom shaft built. In my case, I won't need a gearbox as I will be sitting sideways. Last year's unit used a 73 tooth chain ring at the top, a 13 tooth sprocket at the bottom, and a 16x14 prop. I think this video shows the top end of last year's unit. https://www.youtube.com/watch?v=R-S8MLB_n6I There are photo's of the whole unit earlier in the thread. One of the reasons for using a flexible shaft was to avoid having to use a universal joint. The front end of the shaft will be about a foot above the water and I imagined a slow S curve coming straight aft and then curving down into the water. A universal joint could be needed and more than one strut could be needed. It's possible that I could use a straight carbon shaft if the angle was shallow enough that the universal joint didn't induce too much drag. I will measure the angle between the lower sprocket/drive and the shaft if the shaft was straight (if using a straight, larger diameter carbon shaft). I have some time to figure all of this out, which means I might be able to do it the right way the first time. Thanks again, Rick.
  9. R2AK 2018

    Hello Ace, Welcome to the forum! This seems like a pretty good place to get lots of perspectives on whatever questions you might have. Because the race starts later this year, there could be less wind, which would give the advantage to the boats that are the easiest to human power. It seems that there are now 3 small and slippery trimarans entered solo. I haven't entered yet. I have until Monday. Oh shit, that's tomorrow.
  10. R2AK 2018

    I think that the mastermind behind Bad Kitty's system said that one of the advantages of the surface piercing propellers is that the resistance is aligned with the pedals so that the prop clears the water at the point when the power is the lowest. I don't know much about the compromises, but after watching the system in action I wasn't attracted to it. There's a bit of thrashing going on. I'd like to send a link to this thread to Rick and see what he has to say about it all. Whether I do a stiff shaft, or a flexible one, I think the same drive unit can be used. I could use a carbon tube for the drive shaft, but then a universal joint would be used at an angle that could induce some power loss. I don't want any more power loss (or cost) than I can afford and I can't afford much of either.
  11. R2AK 2018

    Wow, I thought that my 2.2 lengths of chain was a lot. Broderna had chain running all the way across the cockpit from one unit to the other and then another chain running down to the unit. Thanks for the photos. That was the day I had my mast up and down 8 times. Having seen the long, flexible shaft used on the Willoughby style systems, does anyone have reservations about them? My reasons again for going that direction is that it will be very fast to deploy and retract, the chain will be out of the water, and the resistance will be lower than having the prop on the end of a leg or strut. I never could find it, but my friend Brandon was telling me about an underwater video taken looking back at the shaft and prop while pedaling up a shallow river. The prop was bouncing off of rocks and the shaft was bending to stay in the wake of the boat when turning. It's a bit counterintuitive to put a propeller on the end of a long noodle, (I never would have thought of it) but it's one of those things that could be way better than one would imagine, even for a pretty big boat that needs a reliable system. Thanks again for all the help and ideas...
  12. R2AK 2018

    Dean, Is that you? That's the coolest bike that I have ever seen. What does it feel like going 50 on a bicycle? I have been doing a bit of internet searching myself and I found what is by far the coolest pedal drive system I have ever seen. I'm kidding, kind of... https://www.youtube.com/watch?v=Dne6h_hQfUc
  13. R2AK 2018

    I'm a bit dumbfounded at all the pedal drive information that has been posted since I left for work this morning. I agree that I should have a custom chain ring made. I would like to make it robust. Probably still aluminum, but thicker than standard and beveled at the teeth. When I figure out what size to shoot for, I'll ask for help with the design. Alex W, are you willing? I won't go smaller than 13 teeth for the lower sprocket and if I want to use similar prop diameter & pitch, I'll probably end up with at least a 65 tooth chain ring. I was a bit lugged down before ( about 60 RPM), so I think I could go a bit smaller on the chain ring. I have a shop neighbor that could CNC cut and bevel the chain ring. Paul Zeusche, who make the connective hardware for our nesting dinghies can probably be talked into fabricating the lower bearing shaft and associated hardware. I would really like to see a photo of Broderna's system if you have one Alex. Last time I saw Broderna, they were parked on the tip of Saturna with a pedal drive failure. I made the mistake of trying to pedal over a big current hump right there and as a result I didn't much feel like pedaling for the rest of the trip. i did come fairly close to catching them at the end of the following day though.
  14. R2AK 2018

    I never saw the system on Broderna, but now I wish I had. Was it a flexible shaft? Your idea of using a head set bearing is brilliant and the unit that you linked to looks like it could work. A 1" shaft could work for mounting both the shaft and the small sprocket. I'm happy to get your reinforcement on using chain instead of a belt. I know that the gear ratios I used last time worked and I don't want to mess with that. Finding the large chain ring is another puzzle. Somebody makes them, but I think they are custom. The video of "Take me to the Volcano" that Proa posted shows a large chain ring. Does anyone know how to get in touch with Matt Johnson? It would be nice to have a chain ring made that was a bit tougher than my old one because it will be prone to damage. As with my old unit, the first step is to gather all the parts. That's what I'm doing now. Thanks to everyone who posted ideas and links. It helps a lot.