Hydroplaning Rowboat

So--I've been stirring up some trouble here recently on a few threads--Boat suspension and
Stepped hulls- 50 knots plus. Why?, specifically. Already a few irons in the fire, perhaps. Some may have noticed. Just look for copious and really long posts, going all over the place.

What on earth is my problem?

Well, what I'm trying to do here, in life, is break the human-powered water speed record. It's currently held by Decavitator, designed by Mark Drela, a professor at MIT, with a lot of help and support from his team. The speed record was set in 1991, so it's coming up on 35 years. 18.50 knots over 100 meters, flying start. No one has beat it. Hundreds have tried. A few are still trying. Decavitator was awarded the DuPont Prize and hung in Boston's Museum of Science until 2015.

Why do I want the record? Why does anyone want records? Well, it's a challenge to your abilities, and you kind of want a goal to shoot for, to get you through the hard and boring stuff, right? You have to define and limit your optimization space, and have a purpose statement, to keep you on track. Should be ambitious, but small enough to maybe be attainable. There are probably other reasons, for me, but everyone has their own.

I don't know, and it doesn't really matter. Mostly, I had an idea, and I think it's a good one, and I want to see where it goes. The idea struck out of the blue, like a lightning bolt, in March of 2021. It ripped through me, and I suddenly saw about 8 or 9 perfectly patentable ideas in about 35 seconds. It took my breath away. I shot out of my chair.

OK, it wasn't exactly out of the blue. I've been dreaming about this since I was about 12. I'm now 58. It's not like it's been a lifelong quest, but it's been percolating for a long while. Seeing an article on another team's recent project is what reminded me of it all, and triggered the "chain reaction" explosion of ideas and aspects of the device. They're still coming, and getting refined and improved, but I 've been going much more slowly and methodically, now. Still, the game is back on. This is it.

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I already have a patent, for a totally unrelated device. It's a fundamental redesign of the internal combustion engine. ALL internal combustion engines. It is utterly revolutionary, or might be, if it ever works. I've been at it for more than 20 years. Still am, but I need a break. This just to say, I know what it takes to get a patent on an idea, and I don't think small. I sweat the details, and I stick with it.

But I'm over the patent game. Way too much time and effort. And for what? You don't get a million dollars when they send you your little cardboard certificate. It doesn't even protect your intellectual property. In fact, it puts you out there and makes it far more likely someone will snatch your idea, rip you off, and leave you out in the cold. THEY'LL get the millions, or billions, maybe, and you won't see a dime. Not unless you spend all your time and effort suing them and trying to get them to compensate you for damages. Yuck. Read about the Wright brothers, and see how that worked out for them.

Anyway. I don't need the money. In fact, I don't need the record, or to win a prize (there isn't one, any more) or to see this thing hanging in the Museum of Science. Not doing anyone much good, there.

No--what I want, on the small scale, is to introduce to the world to a very different, very strange, really fast, human-powered rowboat. A hydroplane. That flies, at top speed. Gets airborne and skims over the water. And yes, four-point independent suspension and tandem oscillating vertical foils with variable pitch and reversing, asymmetrical foil camber, and chine fences and midships steps and interceptors, and integral full-body or legs-only/arms-only powertrains, your choice, and novel ergonomics and building materials and construction techniques, and...there's more. It's not just another pedal-powered hydrofoil like Decavitator. That's been done, over and over, and it's just about played out. Not very interesting, to me. This is something completely new. NO ONE has tried it, that I'm aware of, and I've searched fairly hard. Aspects, for sure--some very exciting. Isolated elements, yes. But not the combination and synergies.

FUN, huh? Totally nuts. Think of how many sporty types would think it's cool, and buy one, and innovate and improve, and start a whole new class of boat and sport and industry. I wouldn't want anything to do with that--my wife would leave me, and I'd get fired--but someone(s) probably would. And more power to 'em. Go for it, I'd say. Just acknowledge the source, please.

But it's not only that. I know enough to know that if it worked, and "took off"--and that's a very big "if"--the ideas wouldn't stop there. It's big. Like, nudge the field of naval architecture big. Change the nature of rapid marine transport big. Maybe, change the world big. Really. Not me, but someone(s). It doesn't stop with a flying rowboat. You just have to put the pieces together.
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NOW, a caveat--

I'm almost certainly completely full of ****. I almost certainly don't know what I think I know, and my flat-out lack of chops in the areas of, say, math and physics, is totally embarrassing. I have no true, solid understanding of the subtleties of naval architecture, and would flunk out of any program on the first day. I wouldn't even get in. I just can't hack it, and that's not going to get any better. Wrong genetic programming. Not my skill set.

But what if--I know it seems laughable--but what if, I just happen to be right? At least in a few things. What if my totally ridiculous, long-shot, airy-fairy speculations have just one scintilla, one tiny sand grain, of actual merit, among all the piles of junk? I mean, I'm not a TOTAL dreamer. I know a few things. I've worked quite hard at my little hobby over the last four years, researching, reading whitepapers and graduate theses, bookmarking stuff in scientific and trade journals. Talking to people, watching YouTube videos, lurking on fora, zooming with various dingdongs. But also corresponding with a few professional naval architects. And pioneers in related fields. Like Volker Nolte, who revived and popularized the sliding rigger and won the World Championships in single sculls rowing in 1981. He's still at it. He's a coach, now, in Canada. He finds my proposals "interesting," and has tried some similar ventures himself.

So that's my model, and the reason for this thread. I want to pick all y'alls brains. You know many, many things I don't. The things that are hazy and cloudy to me and that I'm totally clueless and wrong about--I need and want and would be eternally grateful if you'd set me straight on. That may be enough that I realize how unworkable it is, and give it up, and go galavanting off tilting at some other windmill. That's fine, and I'd still be grateful for your freeing me from the grip of this obsession.

Or you may be a fellow crackpot who is enthused and energized by the same things I am. You have your own projects and dreams, and the discussion might stimulate and inspire you. Maybe you'll get as much out of participating on this thread as I will. Take as well as give. That would be AWESOME. That "synergy" thing. Like the Wrights collaborating with Curtiss, which they didn't, but could have, and should have, done.

I've started this thread because I deeply value your input and experience and insights, whatever form they may take. Some have already been generous with your time and wisdom, and I can't thank you enough. I hope we can continue, and that it provides something for you as well as for me. Feel free to "check out any time you like," if it's not doing anything for you. But I hope you'll "never leave."

Just a note--if you have nothing constructive to say or a respectful question to ask, please ignore this thread. Those who try to quash or mock the efforts of "content creators" like me--who are trying to present something new and interesting for us to discuss--are NOT welcome, and will be asked politely, or not so politely, to leave. I have no idea what your motivation is--this is supposed to be a forum on boat design, and I'm offering a rather radical new boat design. Don't tell me it's been done before, because it hasn't. (And what if it had?) Do you find ideas that challenge convention threatening? Do you want to do all you can to discourage innovation in the field? Why? Just sniff and scoff to yourself, but don't do it here. We're busy.

Oh--and do not steal. As far as I'm concerned, you're welcome to the ideas I present and any others that may be generated here, but NEVER represent anyone else's ideas as your own, when they aren't. It may be a fine line, but people of honor and integrity know when they've crossed it. Don't. All it takes is a word of acknowledgement.

Allllllllll right. Enough dilly-dallying. Do I actually have anything to say? What about nuts and bolts?

Let's dive right in, shall we?

Please see the attached. It's called "DaggerRo."

 

The design is full of inefficient systems. For example, the friction on the ropes and pulleys. Another major loss of energy is the "elastic foil return". The person has to use energy to overcome the spring force of the foil, which is a huge waste. The hulls seem like a heavy design and not conducive to lift. "Advanced but unconventional materials", is the type of sales hype that has no meaning. Materials are adequate for a purpose regardless of whether they are unconventional or traditional.

 

Whether it breaks the record or not, it's still worth taking that idea as far as it can go. Good luck.

 

"Well, what I'm trying to do here, in life, is break the human-powered water speed record. It's currently held by Decavitator, designed by Mark Drela, a professor at MIT, with a lot of help and support from his team. The speed record was set in 1991, so it's coming up on 35 years. 18.50 knots over 100 meters, flying start. No one has beat it. Hundreds have tried. A few are still trying. Decavitator was awarded the DuPont Prize and hung in Boston's Museum of Science until 2015."

Decavitator won because of a 5 mile per hour Tailwind, which was allowed by the rules. Higher profile may have helped with a sail effect. A propeller driven craft subsequently topped it in a race where there was no wind. The differences in speed between the two craft may not have been statistically significant, and of course it depends on the strength of the particular athlete serving as the motor, at the particular time it was done. The human power boat forum of this list has more info, on this and other aspects, which may be useful or not.. Offered with respect and the attitude that you can see some constructive aspects, in the response. Go for it, sir!

 

Hi, gonzo--thanks for the input. All good points. Well, most, I think.

Yes, there is a lot of friction. The choice to go with rolling cars on transverse tracks, as opposed to a more typical arrangement of a central pivot and a blade on a long shaft sweeping back and forth (Ondulo, Harry Bryan's Thistle, Atsushi Doi's Powerfin and Tandem Powerfin 2, Mark Palmquist's dual fin SUP, gondolas, yulohs, stern sculls), is a tradeoff of higher friction for greatly increased foil travel and better orientation of lift vectors. Which approach will win? That's why we prototype. Both approaches have pluses and minuses, as do traditional oars. There are enough variables that it seems not very productive to try to calculate and predict. Better to build it and see.

Foils on transverse tracks is also not new. There is a single patent I know of that proposes a similar idea in both colinear and tandem embodiments. As far as I know, this design wasn't prototyped. It seems to propose a sliding foil travel rather than rolling (talk about friction!), and the foils are either of very low aspect ratio or are cut off in the interest of space. Foils are solid and symmetrical. A method of variable pitch is outlined, but it's unclear whether or how this is to be implemented underway. Mostly, however, the proposed power delivery method, which would seem to be alternate arm pulls and trunk twists, seems to be both ill-suited to capture the the full power potential of the human body and to be ergonomically horrifying. An aside.

I'm not sure what you mean by overcoming "the spring force of the foil." Yes, the pilot is putting in work to stretch the elastic as the foil travels toward the end of its travel. Of course. She may be putting as much power into "charging" the elastic as the foil is applying to the water, or even more, both happening at the same time during the pull. One can buy elastic exercise bands with a resistance of up to 300 lbs (I plan on starting with about 50 lb per side). But this energy is not wasted. At the end of the pilot's pull, the stretched, tensioned elastic constitutes a reservoir of stored energy that is then "tapped" to drive the foils back to their starting position once they tack--i.e., as the elastic snaps back. One might think it doesn't work, but it does. See?

DaggerRo prototype - "Slapshod Slingshot I"

Yes this is a reversing motor, but the tension is applied by the rubber bands, and the motor is really just taking up slack. You can hear it--it labors on the outbound pull, then spins more quickly back. There are non-trivial hysteresis losses in the rubber/elastic bands, yes. Loss and friction and drag are inevitable in any real-world setup. The goal is always to minimize them while maximizing power and efficiency in other areas.

Palmquist, Doi, and others use elastic in this way. If one doesn't have a rigid attachment to a foil or oar, it's really the only way to retrieve it. It also acknowledges that muscles used during the pull--glutes, quads, calves, trapezius, lats, biceps--are far, far stronger than those used in a traditional rower's recovery stroke (hamstrings, abs, obliques, shins). Using the strong muscles for the pull/elastic charge and using the weaker muscles to simply return the body itself to leaning forward, pulling legs in, and stretching arms out (the rower's starting "catch" position) is a natural fit for the power requirements. I think it'll also be a pretty close analog to the forces a rower experiences in a traditional (sliding-seat) row or on a rowing machine.

(Just related, in the latest design, the rower has been reversed since the attached writeup. She now faces toward the rear as in a traditional rowing setup. I think it does a better job matching momentum shifts. There are other changes, too, but I thought it a better time to start the thread with an out-of-date writeup, since writeups are time-consuming, the design continues to be in flux, and there seems to be some momentum developing in exploring the project, at least between me and montero. That guy.....)

The hulls are now designed to use Coroplast (twin-wall polypropylene) rather than polycarbonate greenhouse panels. Coroplast is already used fairly widely for hobby and novelty boats, as well as folding kayaks such as the "Oru" brand. People are most familiar with it as yard signs, mail bins at the post office, and temporary floor and truck bed liners. Not as strong or impact-resistant as polycarbonate (about half), but 1/4 the cost and less than half the weight. You can buy it at Lowes or Home Depot for about $35 for a 4x8 sheet. It weighs around 1.6 lbs per sheet. Not kidding. An entire float (2'x5', 8" high) with full decks and internal "egg crate" bracing should weigh around 2.5 lbs, without attachments. Not heavy, on this planet or any other. Whether you call this a "sales pitch" is up to you. Whether you call making a boat out of yard sign material is unconventional, or "advanced" because it's unconventional and heretofore unconsidered, or not, also up to you. I'm not trying to sell anything. Saying something is "adequate to the purpose" is a tautology, and I don't see its relevance.

Materials in themselves have nothing to do with being conducive to lift. Planing hull shape does. Unless you mean, "light." Then, yes, light materials tend to make boats lighter, such that less "lift" (let's save that for later) is needed to hold them up.
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Overall, I suspect what you meant to say was, "Gee, Paul, that's kind of an interesting idea, if far-fetched. I don't buy some of your arguments, on first glance, and have some wonderments about what you're proposing. Can you tell me......?" See? Friendly in tone. Not trying to shoot anyone down, or show off, or one-up, or shut down discussion. There is a difference between constructive criticism and attack meant to demean or injure. Attack doesn't forward the inquiry one bit, but constructive criticism definitely can. Keep 'em coming.

 

Thanks, David!

 

Here's the link, discussed in the last few pages of the pedal powered boats forum,

The water speed record that's surprisingly hard to break https://www.bbc.com/future/article/20170921-how-fast-can-a-watercraft-powered-by-humans-go

 

Sssssshhhhhh!!! I know, and I agree with you, but Mr. Drela at least used to participate on this forum, and he might hear you. I believe they were also going downriver at maybe 2 mph. We'll just, um, overlook that, and resolve that WE'RE gonna play fair. In fact, if one's gonna try to get DaggerRo to fly, one might want to row into a slight headwind. Is that "fair?" I don't think the rules specify which way the wind's blowing.

The IHPVA seems to be defunct, as is the WHPVA. They had some spat a few years or decades back. I wrote a few folks, but nothing. But they really put a lot into their rules, and I think they're fair and thoughtful and very detailed. I think they're good guidelines, whether or not anyone's still around to enforce them.

 

A ha!!! THAT'S THE ARTICLE that I read, that kicked me off on my whole "eureka" moment. I thought horizontal whale tails were kind of silly. Not enough travel, bobbing up and down, only pedals, no back and arm....we can do better than that. Let's turn 'em sideways! Shark tails! And hey, what about, like, rails........?

 

I believe there was a human power commercial boat product that utilized the Shark Tale concept many years ago, went out of production after a year or so. A thorough search of the archives may turn something up on that.

 

Are you talking about Hobie Mirage Drive?

 

It does two detrimental things. First, there is always a loss on energy transfer. Second, she can't work at 100% capacity because of having to overcome the spring. Further, that would cause more fatigue.

 

This is neither unusual or advanced as you claim the design is. It is not light either by comparison to even medium tech boats.

 

Nope, that came much later.

Separately, There were several variations based on the Gondola boats propulsion.

One was from a couple of Engineers that built pedal propelled Motors for small boats based in Utah. Separately they had a fin powered boat motor that was extremely simple, a flapping foil at the end of a lever that was push / return, push/return, instead of cranking , wasn't very efficient meant for fisherman in tiny one man pontoon boats.

The other shark fin one was more efficient and part of a boat package that included a flapping fins propulsion was a little larger, just can't remember the name.

In addition to that was the ophira,( oferia?) a very simple foot crank with two paddles attached that alternately dipped into and out of the water. Lightweight and simple as you can get, but don't know about the efficiency.

Plus at least one or more up and down whale tail based drives.

There's lots of topic cross-posting on the forums, so they may be somewhere else than the pedal boat forum, or they might be on the now defunct human powered boat forum not associated with this list.

Ps. Search quickfin and prophish, long gone, poking around may eventually lead to some info,

Search Results for Query: Prophish | Boat Design Net https://www.boatdesign.net/content-search/13768398/?q=Prophish&o=date

 

No argument on energy transfer losses. I'm not promoting it--I wish it didn't "need" to happen--but there it is. Can't figure out how to retrieve foils any other way. The design has to "take its lumps" there, and hope improved efficiencies elsewhere will compensate.

She can't put 100% of her capacity to the WATER, no. But she's welcome to put in 100% effort to the overall system on every pull. It'll take her pulsed input and convert it to (more or less-ish, kinda) constant output. No "coasting" of the boat.

Here's the argument for that. Say a traditional shell has an 8 ft oar, 2 ft from oarlock to handle, 6 ft from oarlock to blade tip. Looking at a single oar, circumference at the blade tip is then roughly 2 pi r, so 36 ft. Say a third of that is travel through the water. 12 ft, per pull.

With this oscillating foil setup, I don't see how it's practical to get more than about 6 feet of blade travel per pull, per blade, without doing even more pulley gymnastics and making the thing more untenable than it already is. So to soak up the power on the pull, regardless of comparative efficiency, you either have to use a considerably bigger blade or pull at a higher (and less efficient) AoA--or, if you don't want that, but you have "power to burn" because of the short blade travel....and you need to get those foils back anyway, somehow.....and to plane (yeah, right), you probably want constant rather than pulsed power.....well, why not? Lemonade from lemons. Maybe.

As for fatigue, she doesn't know any better. She thinks she's rowing her regular boat, same effort, same resistance. She even thinks she's on a sliding seat instead of a fixed seat/sliding footplate. Only difference is that it seems like the boat isn't slowing down on her recovery, so much as speeding up or at least staying constant, and kind of giving her a boost as she leans forward to the catch, vs. what she's used to. Weird. Like it's self-propelled. And it doesn't accelerate or surge as fast on her pull, either. Maybe it doesn't accelerate at all, just stays steady. What the heck? That's annoying. But there's that weird powered recovery. Hmmm.