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      Abbreviated rules   07/28/2017

      Underdawg did an excellent job of explaining the rules.  Here's the simplified version: Don't insinuate Pedo.  Warning and or timeout for a first offense.  PermaFlick for any subsequent offenses Don't out members.  See above for penalties.  Caveat:  if you have ever used your own real name or personal information here on the forums since, like, ever - it doesn't count and you are fair game. If you see spam posts, report it to the mods.  We do not hang out in every thread 24/7 If you see any of the above, report it to the mods by hitting the Report button in the offending post.   We do not take action for foul language, off-subject content, or abusive behavior unless it escalates to persistent stalking.  There may be times that we might warn someone or flick someone for something particularly egregious.  There is no standard, we will know it when we see it.  If you continually report things that do not fall into rules #1 or 2 above, you may very well get a timeout yourself for annoying the Mods with repeated whining.  Use your best judgement. Warnings, timeouts, suspensions and flicks are arbitrary and capricious.  Deal with it.  Welcome to anarchy.   If you are a newbie, there are unwritten rules to adhere to.  They will be explained to you soon enough.  
Russell Brown

R2AK 2018

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On 1/15/2018 at 1:35 AM, RickW said:

For pedal drives on an 8t catamaran I fitted a combination of Mitrpak boxes to large model aircraft props after observing the buckling issue with a curved shaft.  The eventual fold down drive legs were very effective.  Two people could sustain around 2.5kts. The first year on they gave considerable advantage up the Derwent in light, flukey winds.  In the photo below you can see the pedal drives folded up with the big two bladed prop resting on the seat back.  The first iteration were drop-in drives and there were times when the pedallers could not not slow the prop down to release cleats when they were motor sailing.  The idea of the prop thrusting against the transom then folding up when unloaded was an essential to avoid that condition.

 pretty picture.  

If you want to get into detail on a pedal drive for a specific application it is best to email me:

rickwill@bigpond.net.au

 

Peccadillo_3peaks.png

Wow.  Is that a Chris White Atlantic 46 cat? 

And two folks can move it at 2.5 knots sustained under pedals alone?!  To me at least that is freaking amazing.  Its a big boat that is not super light and has lots of windage.

If you don't mind another question, what type of set-up would you recommend for a small trimaran.  Lots of F27s do this race... as well as similar tris. Being an F27 owner and interested in the race I am starting to try to understand my options...

That is amazing stuff you did for Peccadillo... in my ignorance I would not have thought it possible.

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10 hours ago, RickW said:

Russ

I doubt that a curved shaft would be very useful in your set up.  My choice, without gearboxes, would be two toothed belts with a common middle shaft just below the bridge deck that allows the bottom of the leg to flip up sideways.  You can mount 14T pulleys for a T10 industrial belt inside a 50X50 aluminium tube.  Two shorter belts are no more expensive than a single long belt.  A 310T 16mm belt here costs AUD168 While 156T belt costs AUD56.  I usually use 24mm wide belts on crank pulleys bigger than 32T.  These allow maximum power from most adult males.  For pure endurance use the 16mm wide belts are adequate.  The black Twin-8 in earlier links only has 16mm wide belts and it has done more than 1000km including one MR340.

Bicycles have a constraint that these drive legs do not because the rear wheel is on the centreline requiring the chain to be offset.  Although the bicycle parts are convenient they are quite bulky compared with a belt drive or heavy duty chain.  Also the bicycle chainring overhangs the shaft so shaft flexing causes chain misalignment.  To avoid corrosion issues experienced with chains, I tried the Gates carbon drive belt and found the drag on the centre track was horrible.  A standard T10 belt rides off the pulley if the pulley is mounted on a crank arm spider.  That indicates the drag required on flanges to keep the belt on the pulley.  With a toothed belt the pulley can be supported by a bearing either side; meaning shaft flexing does not cause misalignment.  In fact a toothed belt on a properly supported shaft is more efficient than a typical bicycle chain when they are under load.  

The crank pulley would be say 42T to give you a 3X ratio to a 14T pulley on the bottom of the crank unit then two 14T pulleys inside the bottom part of the leg.  The bottom part would need to be braced so it could be held down against the prop torque as well as a means of lifting the prop. The intermediate shaft needs to be of sufficient diameter to take the bending moment from the thrust although it would be possible to have a fore-aft brace that pivots in line with the centre shaft to eliminate the bending moment on that shaft.

The belts in use on about 10 boats over the last three years are maintenance free.  There is no messy lubrication.  They will operate in water but the belt teeth tend to create a vacuum in the pulley teeth so they get noisy when wet.  It is not particularly difficult to exclude water to a satisfactory level.  Unlike a gearbox or even chain the belts do not deteriorate in water.  The aluminium pulleys get some surface corrosion though. 

Rick

 

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

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Russell, I have a SeaCycle I'm not using if you'd like to borrow it, but it's in Victoria.

I've organized a tour of the Joint Rescue Coordination Centre Pacific ( JRCC ) here in Victoria for 1000hrs, Friday January 23rd followed by a tour of Marine Communication and Traffic Services ( MCTS ) at noon, also here, in Sidney.

Maximum 10 people. I'll give R2AK entrants booking priority, race applicants next priority, and wanna-be dream racers third.

PM me an E'ddress and we can confirm details. Full names, addresses and date of birth required for security clearance. Unfortunately, we cannot accept any non-Canadian guests at this time, no offence, it's just way more complicated.

First come first serve.

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4 hours ago, Russell Brown said:

 

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

Russ

I do not charge for design work unless it has commercial value.  I usually make some money from the bits and pieces I supply for pedal boats and pedal drive units.  However I only make special parts that are not available off-the-shelf.

The concern I had for the sideways swinging leg was if there was enough cockpit width to park it hard up under the deck.  I doubt a 50mm faired bump hard to the bridge deck would cause much drag.  But there may not be enough width available for leg length required to get the prop submerged.

Depending on the overall length you have available there is the possibility of using a stiff aluminium tube to get down to water level then a shorter length of curved shaft to get the prop perpendicular.  There would need to be a CV joint or universal joint where the tubular shaft connects to the horizontal shaft.  Single universal joints at a relatively high angle are feel jerky to pedal.  The more complex joints cannot take any thrust meaning both shafts need to be supported and aligned.  That becomes complex.  

One of the designs I came up with has a belt box with nominally 5X ratio that has a double universal joint attached to an inclined shaft that is mounted off the belt box. That then connects to a 17-7 stainless curved shaft.  The shaft has a thrust absorbing strut at the prop that allows the prop to be lifted.  As stated before the allowable vertical drop with the 2.4m shaft is 500mm, which limits the diameter of the prop. I have attached a sketch of this arrangement that was designed for a Tornado cat.  The drop can be extended by adding an inclined straight section but that means it is longer.  The double universal for this design that I could find had a price tag of AUD168.

Rick

 

 

Screen Shot 2015-10-29 at 12.11.51 PM.png

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5 hours ago, Wess said:

Wow.  Is that a Chris White Atlantic 46 cat? 

And two folks can move it at 2.5 knots sustained under pedals alone?!  To me at least that is freaking amazing.  Its a big boat that is not super light and has lots of windage.

If you don't mind another question, what type of set-up would you recommend for a small trimaran.  Lots of F27s do this race... as well as similar tris. Being an F27 owner and interested in the race I am starting to try to understand my options...

That is amazing stuff you did for Peccadillo... in my ignorance I would not have thought it possible.

Wess

If you have the room to sit sideways and don't mind facing sideways then belts are the best option in my view.  Gearboxes were the obvious choice for the Chris White cat because the transom steps provided a neat mounting point for for backward facing engines.  Those units were not needed to push against wind.  The 2.5kts was in dead calm.

For side facing a faired tube with a belt inside is a simple way to go.  This is simple top engineer and easy to make from aluminium sections.  Either pivot the leg at deck level to park it or have it drop into a deck  well.  

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Below, a photo of Sidecar’s faired electric drive leg. As Rick says, the belt and pulleys are inside the 50x50mm tube. The drive shaft drops through a slot in the cockpit floor and can be rotated and operated through pretty much 360 degrees.

 Next big challenge is getting it to pedal as well from one position and still rotate as well...... so that I can still use it in either direction, or in the case of a cat or tri, be able to pedal on either side, without back-pedalling.

2C248DC0-A912-4C4C-BF64-6843D48B4482.jpeg

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4 hours ago, RickW said:

Russ

I do not charge for design work unless it has commercial value.  I usually make some money from the bits and pieces I supply for pedal boats and pedal drive units.  However I only make special parts that are not available off-the-shelf.

The concern I had for the sideways swinging leg was if there was enough cockpit width to park it hard up under the deck.  I doubt a 50mm faired bump hard to the bridge deck would cause much drag.  But there may not be enough width available for leg length required to get the prop submerged.

Depending on the overall length you have available there is the possibility of using a stiff aluminium tube to get down to water level then a shorter length of curved shaft to get the prop perpendicular.  There would need to be a CV joint or universal joint where the tubular shaft connects to the horizontal shaft.  Single universal joints at a relatively high angle are feel jerky to pedal.  The more complex joints cannot take any thrust meaning both shafts need to be supported and aligned.  That becomes complex.  

One of the designs I came up with has a belt box with nominally 5X ratio that has a double universal joint attached to an inclined shaft that is mounted off the belt box. That then connects to a 17-7 stainless curved shaft.  The shaft has a thrust absorbing strut at the prop that allows the prop to be lifted.  As stated before the allowable vertical drop with the 2.4m shaft is 500mm, which limits the diameter of the prop. I have attached a sketch of this arrangement that was designed for a Tornado cat.  The drop can be extended by adding an inclined straight section but that means it is longer.  The double universal for this design that I could find had a price tag of AUD168.

Rick

 

 

Screen Shot 2015-10-29 at 12.11.51 PM.png

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...

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2 hours ago, Russell Brown said:

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...

OK - it is probably time to do some layouts.  An inclined shaft with a universal joint is possibly a workable option.  If you are starting out only 250 above the waterline then you may get away with a single curved shaft.  I have used my folding prop with submergence less than 250.   There is benefit in having the prop closer to the middle of the boat than right aft or even behind the transoms.  Generally a pedal drive is used in calmer conditions so pitching is not too bad but the closer it is to the longitudinal CoB the better from a ventilation perspective.  With a small cat, that lists with the weight of the pilot, there can even be benefit in having the prop off centre as a prop nearer a hull is less likely to ventilate in a beam sea. Also the centre of resistance is offset from the centreline so the thrust line for neutral helm is offset as well.

I do not know at what angle a single universal joint feels jerky but I have never used one with an angle as low as 12 degrees.  I would usually opt for a double to smooth the torque but a single might feel OK at lower angles. 

I have not looked through the entire thread to see if you mentioned the size of the prop you are using.  My folding prop is only 330 diameter so it requires a submergence of about 260 at the hub centre where I locate it to avoid ventilating in waves; typically only 1m aft of the CoB.  

With regard to sissies, one of my inspirations for pedalling on water was a great uncle, a WW1 veteran, who never got a drivers licence.  He cycled everywhere until he was 92 when his diminishing eyesight limited his ability to cycle in traffic.  With that as a reference, I figure cycling is good for my health and longevity.  There are not many forms of exercise more enjoyable than being in a reclined seat pedalling a boat at a nice pace over water - weather provides variation. People I know who have built pedal boats inevitably lose weight. Being able to hit 10kts under my own power at my age is quite satisfying.  

 

 

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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.

 

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Holy pedal drives!

I fell asleep part way through this thread (since we don't have a multihull and a pedal drive wouldn't work), even though it was quite interesting reading in terms of learning something new.

And, now, I just realized/remembered (we've never used it) that the Cal 20 of course has an outboard engine well and accompanying opening on the bottom of the hull.  Am brainstorming pedal drives  in my head now (instead of rowing set up)...once we get our registration in, that is - tomorrow!).  Pedalling while facing aft, something could probably be rigged up...

(Maybe as a back up to oars after one gets tired of rowing a 2000 lb monohull! :-) )

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53 minutes ago, Jud - s/v Sputnik said:

Holy pedal drives!

I fell asleep part way through this thread (since we don't have a multihull and a pedal drive wouldn't work), even though it was quite interesting reading in terms of learning something new.

And, now, I just realized/remembered (we've never used it) that the Cal 20 of course has an outboard engine well and accompanying opening on the bottom of the hull.  Am brainstorming pedal drives  in my head now (instead of rowing set up)...once we get our registration in, that is - tomorrow!).  Pedalling while facing aft, something could probably be rigged up...

(Maybe as a back up to oars after one gets tired of rowing a 2000 lb monohull! :-) )

But that is sort of the point that is maybe missed.  I came in here thinking that for sure I would do 2 sweep oars (one on each float) of my F27 which is 3000 lbs BTW and so more weight and windage than what you are talking about. But what I got back was lots of PMs saying go pedal drive its more efficient.  And I see other F27 owners doing that.  So pedals are maybe more efficient even for you monohull.

Not that I have the slightest idea yet row to build rig them but I am listening and reading!!

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2 hours ago, Jud - s/v Sputnik said:

...And, now, I just realized/remembered (we've never used it) that the Cal 20 of course has an outboard engine well and accompanying opening on the bottom of the hull.  Am brainstorming pedal drives  in my head now (instead of rowing set up)...once we get our registration in, that is - tomorrow!).  Pedalling while facing aft, something could probably be rigged up...

Have a look at the (Searunners) Seascape 18 drive setup from the 2016 R2AK , that was an outboard well job from memory.....

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56 minutes ago, Sidecar said:

Have a look at the (Searunners) Seascape 18 drive setup from the 2016 R2AK , that was an outboard well job from memory.....

Great - thanks a lot for the reference.  Will definitely check that out.

(The good thing about oars is that, for this year, a rowing set up will be easy-peasy to set up as compared to a peddle drive.)

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3 hours ago, Russell Brown said:

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.

 

I took the sissies comment in the spirit it was intended; with a smile.  Also most of the design work I do for pedal boats is for guys and gals in North America.  The fellow I am working with on commercialisation of a boat lives in Texas.  The fellow that supplies the 17-7 shafts in another Texan.  A fellow in Missouri has made moulds for building the Twin-8 and V16-62 hulls.  The 6.2m hull he made for Greg K weighs just 5.2kg:

I am also privileged to do design work for Matt Johnson who has the biggest engine of anyone I have worked with.  He can still sustain 300W for a couple of hours.  He is planning to just pedal to Alaska this year.  He is reducing the weight of Rouleur right now by eliminating any sailing gear and using lighter materials in some areas.  Pedalling a boat that moves easily is good fun.    I just took your sissies comment as an opening to explain why I started playing with pedal boats 15 years ago and promote what I feel are benefits.

I gather by Brandon that you are referring to Brandon Davis of Turn Point Design.  I had some input on the pedal drive that Brandon Davis set up.  He started out with the idea of a curved shaft but steered away from it after I pointed out the challenges. He also had one of my folding props but decided to go for a bigger diameter prop after playing with JavaProp.  My prop is really suited to easily driven boats although it has been used on a couple of reasonably heavy R2AK boats; both much heavier than Matt's Rouleur.  Brandon has commented on the ease he can move his little cat under pedal power.

I will await some layouts. 

 

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4 minutes ago, Jud - s/v Sputnik said:

Great - thanks a lot for the reference.  Will definitely check that out.

(The good thing about oars is that, for this year, a rowing set up will be easy-peasy to set up as compared to a peddle drive.)

I have just found a video of Searunners: https://r2ak.com/2016-clip-of-the-day/

Day 22, it is an in cockpit drive facing aft but with the driveleg off the stern...  Apologies.

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On 1/11/2018 at 3:37 PM, lasal said:

Here is an off-the-shelf system http://www.h2proped.com/

I've never used it but I'm posting it because it looks adaptable to a variety of boat types and cockpit configurations with the flex drive. At $750.00 for a complete system it seems priced fairly too. I like that the gearing is compact. I can't comment on it's efficiency obviously, but the drive leg looks clean.

Alex W.'s posts are accurate and helpful on bike part specs.  There are many specs to consider if building your own system, and as Alex just pointed out you'll want to stick with a 3/32" pitch chain, chainrings and cogs. Also consider crank length, bolt pattern, BB spindle type and shell, pedal cadence targeted by gearing, etc, etc. I think Kim Bottles did a bunch of work on a pedal system a while back.

I have used the Mirage system and the low end torque does feel strong and I agree that might be a good thing on a relatively heavy sailboat. Installation, however, would be difficult on most sailboats.

Good luck to this year's competitors!

 

p1110301-2_orig.thumb.jpg.e1c625a49f3b926bfbec9a71444dd415.jpg

Team Pear Shaped Racing installed the H20 ProPed pedal drive system on our Multi 23 trimaran. What we discovered was that the stock flexible cable was not able to handle the torque involved in propelling the fully loaded (550 kgs) boat, and would bind up in the metal tube designed to limit flex under power.  The original design sports a 90 degree deflection from the pedal unit to the cable, as it runs aft through the transom of the boat, in the forward-facing pedal position.  We replaced the stock tubing with a straight tube, changed the pedal orientation to athwartship, and tried it again, but still ended up binding the flex cable due to the torque.  As a result, we could not achieve a sustainable pedaling cadence to power the boat at the target 3 knots of boat speed.  We also experimented with different prop pitches, to reduce torque (with considerable input from Brandon, at TurnPoint Design), but that didn't work either.  In the end, we installed Mail Order Bride's rowing stations, and were able to achieve 3-4 knots of boat speed through Active Pass, against 3.5 knots of current on Day 1 (before hitting the log, early the next morning).  Let me add that rowing the Multi 23 was a hate mission due to the large dihedral, which made it extremely difficult to balance the boat so the Canadian and I could maintain consistent rowing cadence.  We canted the rig so that one of us would always be lower / higher than the other, but every time a BC Ferry came by, we were screwed.

Suffice it to say we will be investing significant time and effort to design a workable pedal drive for "Dragon" for 2019.  We have our top Canadian engineers Googling solutions as I type...

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