Stepped hulls- 50 knots plus. Why?

The speed improvement comes not from the vents, but from the steps. As a side effect of the steps doing their thing, they drive water downwards as the hull passes over. The downward movement of water causes a low pressure pocket behind the step. A very big one. LOTS of drag. You MUST relieve that low pressure, or your step is basically sucking your boat backwards and down.

Thru venting to the deck is the cleanest way to do that, I argue. With traditional "side venting" at the waterline, you're fighting against the sideways, outward flow of water from deadrise when you're trying to pull air in toward the center of the boat. Plus there's just the water itself blocking off the openings until you're up on plane. The drag makes coming up on plane harder and more power-consuming. Once you're up, a wave or the boat's up-and-downing might block the opening again. All most unsatisfactory. Just vent to the top, like popping a soda can. Fairly large cross section, and all the way across, to make sure flow restriction doesn't interfere with getting that vacuum OUT of there.

This all works even better when you have no deadrise or planform taper, I suspect. And when you use chine fences. Now you have a contained air pocket, no water flowing out to the sides or other complications. Just suck that air through, nice and smooth. I'm not going to touch "air lube," other than to say that the air has to go somewhere, doesn't it?

 

Sorry--I didn't start this thread, just sorta revived it. My own goal, not the OP's, is to challenge for the outright water speed record in the human-powered category for the 100m flying start and 2000m standing start events, as sanctioned by the Internatioinal Human-Powered Vehicle Association (IHPVA), now apparently inactive. My prototype is a planing rowboat that uses tandem, vertical oscillating propulsive foils mounted on rolling cars that are pulled along round, transverse rails by the rower pulling lines, much like a rowing machine. There's a lot more to it, but that's the bones. It is entirely original and novel in many respects, based on a fairly thorough survey of patents and literature in the discipline. Pure maximum speed over the prescribed distances on a set power (and torque) input is the only goal. Design parameters are unrestricted except for the requirement of human power. There is no fuel. Any seakeeping or handling considerations are non-existent for this effort, and at best secondary if one takes a view to someday modifying this design to have recreational appeal, on the fairly remote chance it breaks the record, or even shows much promise.

 

On this one, the boat isn't built yet. It's under design and constant revision. I have two model prototypes in a state of partial construction, but the design is still fluid enough that it keeps changing before I get a prototype complete. When I say "change the AoA," for instance, I don't mean change the trim of a completed boat, I mean change the lines on a drawing. "As AoA increases" means I erase the earlier line and replace it with another, or use the "rotate" feature on my PowerPoint. Yes, I'll probably get and learn CADD, someday.

I sometimes speak as if the boat is a done thing, because it is quite real, in my head. I have "hyperphantasia," so I build it, drive it around, test it, watch what it does, observe results, see flaws, fix them, rebuild.....all without buying a supply or making a cut or drilling a hole. When I have a question, I do more research to see what others have done or theorized about or observed, or talk to a specialist in a related discipline, or zoom with the guy (or gal) who built something I like, or, hey, participate on a forum, until I learn what I think I need to know and make the changes I think I need to make. Then I "build" it and "test" it again. I'm on version 6, at the moment, transitioning to version 7. It wasn't originally tandem, it was opposed. It didn't have steps at all. The rower used to face forward, now he faces backward. It didn't used to have variable pitch or reversing camber on the foils. It was sliding seat, not fixed seat/sliding footplate. It used to be made of polycarbonate, now it's being made of polypropylene (Coroplast). Etc., etc. I can't build a lick, even models, but I have a very vivid and pretty realistic imagination, and I research goodly. I am what one might VERY kindly term a "novice" engineer. And an even more novice physicist. Would not dare to claim the title of even the rankest amateur naval architect.

What I am not, however, is a novice inventor. I am an extremely experienced inventor, and I'm rather good at it, by now. Sorry. I hold a US Patent that I wrote and prosecuted myself, on an HCCI free piston-gas turbine engine. I've been at that project for over 20 years, and I'm not done yet. Four full-sized prototypes, none quite working. My current boat idea is good for probably 8 or 9 patents (and I should know) but I don't want to go through that process again, as life is too short. On the engine, I locked myself into a fatally flawed design with my claims, so the whole patent's useless (and now lapsed). There are better ways to spend one's time.

It's all dimensioned and sourced, FWIW, although that's sort of a moving target as well. I'm really good at internet shopping. Beats working for a living. Speaking of which...

 

You should start a new thread on this topic.

 

Sigh. Ok, you're right, of course. I appreciate those who've followed, and your great input.

Just--PLEASE don't agitate me by telling me or intimating I have no business being on a forum with qualified engineers and naval architects. I'm an inventor. I really am--it's what I do when I'm being me. I don't KNOW the box that I'm thinking outside of. That's why I 'm here --to learn and give an outsider's perspective to challenge and maybe interest those--you guys--skilled in the art. Maybe inspire you to look at things you already know, in a new way. Give you the fun of mentoring, if you like that.

I'm not totally ignorant of the field--I hope that's pretty clear--but some--probably a lot--of my musings are clueless or flat-out wrong, and I welcome and appreciate corrections. Just be gentle, and stick to the specific claims and substance of the arguments. Cryptic pronouncements don't help me, or probably anyone. Snide remarks are destructive to all and to the tone and tenor of the thread. There have been some here, predictably, and I try to ignore them. Two of you are prime offenders. I'd remove you from the thread if I could. I WILL report another abusive post along those lines. You know who you are. I am sharing, here. It's an act of trust. I'm supplying the grist for us all to think and argue about. Do NOT sneer at that gift. Got it?

Above all, do NOT rip me off and try to represent my ideas as your own. I've worked very hard on my design and everything associated with it, for a number of years, now. If you think some ideas are good, great! Feel free to share and discuss elsewhere and incorporate into your own designs. But do give me credit. Just mention my name and where it came from. My name is Paul Schwiesow. I live in Denver, CO. I'm 58. I'm an ex-English major. My profession is irrelevant and fairly stupid. But I've been an inventor basically from birth, with interests in all kinds of stuff--boats, airplanes, engines. Cycling. Rowing. Tree-hugger. Not very good shade-tree mechanic. Dinghy sailor. Know motorboats and waterskiing from youth. Dad is a retired atmospheric physicist and engineer (and inventor) with similar interests, and we spend a lot of time together talking "shop." It rubs off.

I don't own any boats or boat much, these days. Tinker and build only when I feel I have no other options. I live in my head. Might as well consider me housebound. Or disabled. I'm not, but in some senses might as well be.

Ok. Enough. I'll start a thread in the not too distant.

 

I spend long time researching cars , bikes and other vehicle suspensions and definitely won't do anything with PVC pipe , except illustrative model.

Here on the forum is thread "boat suspension" .

Returning to stepped hull design it's tempting to make bigger 1.5m models with adjustable step height , adjustable chine fences .

Vintage Wetbike like setup comes to mind as an option/development of steppet hull . Aft part shaped rectangular from above with classic up going bow , with pivot/ pantograph mounted for adjustment , front giant ski bow .

 

I'll look forward to it.

 

@Horton HCCI why do you think applying high speed hydro hull to HPV have any sense?

Can't you see that at low speed it's only water plough ?

 

Well, I DID say I was probably full of it. .

Take a look at this for some stats on those kinds of beasties:
Class Information – SCSC Racing
If those are O 250 class, then per this: Excalibur Hydroplane Racing - excaliburmotorsports, that might correspond to "Sportsman "C" class in the "Class Information" link above. Class C is 440 lbs boat and pilot. Speed they don't say.

Junior Hydroplane says 320 lbs, 15 hp, low 50 mph. That's with a restrictor plate, unspecified, but other places say that limits them to about 8 hp. WAY more than the about 0.6 hp a human can sustain, or an absolute, 5-sec peak of mabye 2.5 hp for a world-class rower. But we don't need low 50 mph. More like maybe 23 (20 knots). Note that removing the restrictor and going to the /Sportsman"A" Limited Hydroplane only gets you from low 50s to upper 50s. It's gotta be mostly air drag at those speeds. Drag goes up roughly with the square of speed, as we all know.

I grant that this float shape makes for a TERRIBLE displacement boat. The worst possible shape. If it can't get up on plane, floats should be redesigned with considerable vee and deadrise, tapered stern, a bit of rocker, maybe. That won't be breaking any speed records, but could be an OK boat for fun or other uses.

But even if it's the worst possible shape for a displacement boat at sub-planing speeds, if it can just get over the hump, then it's the BEST possible shape for planing, high speed or no. And the flat bottoms, square nose, sharp and square transom, etc. are actually the best shape to pop up over the hump and get on plane very quickly, too.

How slow can a boat go and still plane? Each float is 1.5 m long. Hull speed for each float is 1.5 m/s, or 3 knots. It will plane at 6 knots, I bet you a Euro. Ok, a zloty. If my oscillating foil setup is any good, I should be good to sustain 6 knots for quite some time. Of course, it may not be any good. You may stick a pedal-powered rotary propeller in it, and we can race. About time for me to leave my country, anyway. Hope you have a spare room.

If you've ever seen those model airplanes that are very, very light and have lots and lots of wingspan, they can still fly, even very slowly. That's the idea here. Take a an unlimited hydro, scale it down about 2:1, and make it approximately 4 percent of the weight, pilot included. Make the sponsons about 5 times the area, and the wings at least three times the area, proportionally. It almost surely won't generate any appreciable air lift until about 10 knots, and couldn't hope to clear the surface until maybe 15. But at 15....




Go to https://www.omnicalculator.com/physics/lift-coefficient and play with it. Play with it for a long time, as I have. Water and air both. My weight is 273 lbs gross, floats 60"x22"x8" (times four), wing plus angled fuselage plus tail 128"x90", or about 80 sq ft. A bit bigger overall than a Sunfish sail. Have fun!

 

A much better idea is to use some 4 surfboards. Have you ever seen a board with a step? Are all boards slow? Do they have problems with planing?
Hydro 15hp = 150kg of thrust. 150kg is not a small amount. Far beyond muscle propulsion.
You often throw in tandem type ekranoplans like Jorg. These are completely different machines.Some of them are able to hovering at almost zero speed . Thrust vectoring.

 

If we're talking about full-sized HPVs, "surfboards" are far too heavy, and far too long. Would never work. However, what are called "boogie boards" might work, and I've considered them. They are even lighter than my proposed floats (less than a kg each): example.



Steps are probably not needed. I think they would help, but they are complicated. Just using pre-made boogie boards like this would be far easier. If they break, oh, well. They probably won't.

Wings are not needed either. Joerg-type boats like the ones I linked to use PAR thrust, but note that they have no floats. They start with their wings in the water. OK if you have a lot of power and air thrust, and you intend to be fully airborne, you can do that. They are designed to be airplanes. DaggerRo is designed as a boat. A planing boat, if that can be achieved, and if not, OK, maybe a displacement boat would still have some usefulness. If it CAN plane, then wings would certainly be optional.

The deal is, I think I have to have a very wide stance simply due to the propulsion method I favor--the oscillating foils. If it's already that wide, there is a whole ton of empty area between spars. Well, why not pull some fabric over that area, try air wings? Doesn't weigh much. Not that hard. Might not help, and might hurt. If it doesn't work, oh well. Worth a shot.

 

You know--you're making me realize that I'M the one making this too hard.

Well--foils are not easy. But they're the heart of what I think I bring that is new. Very, very long transverse travel, at least two, more like 3 or four times the travel, of any other oscillating foil setup that's ever been tried. And SERIOUS torque and power--not legs or arms only, but this:

Look at how long her pull is, and add another foot and a half, because of the way I've added mechanical advantage on the leg drive. SERIOUS travel. SERIOUS power. HUGE stroke and "useful sweep,", for a sculling setup, on blades 18 inches deep and 7.5 inches wide. Not some pissant rotary propeller with a useful crank travel of at most ten inches. No, the pull travel alone is 5 feet, for a big boy. I'm not farting around. A linear propeller with an equivalent blade sweep of three ****""*""" feet in diameter. A meter-diameter rotary propeller equivalent. In WATER. Transverse, not rotary sweeping. That's utterly critical.

But it's not enough. I'm convinced it simply must have variable pitch, to be able to utilize all that power, if you really want to go somewhere fast and not just putter. That's very hard to come up with an approach for, although not nearly as hard to execute. Like adding suspension or steps or wings, it's not necessary for proof of concept, but if you're going to be doing it anyway, you might as well go all the way. Stopping with a crude setup, like solid blades and simple, passive hinges with stops to set a fixed pitch, is kinda boring. Like this:

I mean, that's great, and thank you, Mark Palmquist, for your work in making a prototype that would take me a year, so I can see that what it does is about what I would expect it to do. Cool to see in action. But if you hate building things and would prefer to keep exploring, like me, you build it in your head, look at it, observe it working, frown, and try something better, with more potential. Might not work. Probably won't. But if you "can't" build but are good at throwing out and exploring many ideas, and researching whether they have theoretical potential based on the literature and related prototypes, well, that's what you do. I'm such a bad builder I figure I only have one attempt. Or at least, I must try to put in all my "refinements"--my experimental stuff--at once. I already "know" what simpler stuff will do, in my head. Not worth the effort, for me, of building something where I already know what its limitations will be, and where I've already convinced myself there's a better way to address them.

I'm a pure inventor, not a builder. Like Tesla, I build and try out many, many examples in my head before I even try to cut or glue anything. By the time I get to cutting and gluing. I already know what's wrong with it before I'm even halfway through.

My first model broke, and is way too slow, and the pull pins atop the foil are too far apart. And the floats are way too small, and the rear floats should be wider apart to match the front, etc., etc. If I had the skills of Daniel Riley, "rctestflight" in the first ground effect airplane above, I could have prototyped a model in a day or two, or at most a week. It takes me more like a year and a half to learn my lessons. I get bogged down in the details, and try to do too much at once.

I understand my foils. They're fairly sophisticated, but I know what I'm doing and why. I understand my lines and pulleys and elastic, and I know it will work. I know my sliding footplate will work. I have already proven to myself all my four "cars"--foils and pull handles--will work, very well indeed, far better than I expected.

Where the foil tracks (tubes) pass through the fuselage, is tricky. It's an opportunity to support the tracks against the fuselage in the middle, that really can't be passed up. They are very long and skinny. They will bend. My coat hanger wires on model one do, and it's a problem that needs solving. I believe I've solved it (U brackets). Just need to put it into practice.

 

Stick your posts to "Hydroplaning rowboat" because they concern human propulsion more. You write in "stepped hull". People sometimes look for information.
We are making a mess.

 

Good idea. I was about to suggest the same thing.