Pedal (assist) boat prop pitch

I don't think I made any prediction as such re if it will plane or not - pretty much anything will plane, even a solid concrete brick, if it has enough power to get it up on the plane.
I was just expressing concern about your ability to get the boat 'over the hump', and then keeping her there on the plane.

Even just 2 hp is still almost 1.5 kw - yet I see above that even a Tour de France rider cannot sustain an output of more than 400 watts for very long.
Can 100 watts of power keep your boat on the plane?

 

I quite firmly think that the analogy of e-bike in an uphill is not well fit for a boat.
Actual 1.5kW ca propel a bicycle 60kph and up steep hills. Our “mopeds” used to have power limit of 1.5 hp. Now bike will probably end up in situations where the system is unable to deliver anywhere near the 1.5kW even if that is the system rating. If at low rpm it doesn’t have the torque then it certainly doesn’t have the power… (power being the result of multiplying rpm with the torque).

This is bit of a sides shoot: Boats don’t coast, they have no high torque low speed scenarios. We see frequently posts that try to up-sell electric power as if electric hp was more than gas hp and low rpm torque is usually brought up. With boats and props spinning the prop slowly is always low torque situation. The demand for torque goes up with speed.

So even if e-bikes have inefficiencies your boat cannot have them or you better not count all 1500watts in your calcs. My point is compared to the 1.5kW let alone 8kW the human element is almost a rounding error. 300W burst is not comfortable for many people so to design a vessel that requires that last 20% to get on plane seems dubious. Either it gets up with the 1.5kW or it doesn’t.

And I can see electric hybrid fir example a pedal kayak type of a vessel with a 200W solar setup and a 5kg LFP battery. Solar might give almost adequate camping performance at 5knotts but run short on long days. With muscle power supplementation it could work quite nicely. I just don’t think that human power is quite enough for planing. Uffa Fox did the Best Boat, a sculling boat in 2 versions: planing and displacement. in the end the top speed was pretty much the same. Quite impractical boats for general recreational use and nowhere as fast as we would like.

(And I totally get the appeal of e-bicycles, I have done motorcycle enduro and going to the forest with a MTB especially on uphills seems torturous. With a bit of boost the game changes)


And thanks for the patent post. Makes sense as an asset to prove legitness of a startup, innovation etc.

 

"I used to think the same thing until I had it explained to me some years ago by a very rare person- an inventor that had accrued considerable personal wealth out of selling an invention!

.....But this is not a valid reason to give away or blow your IP. If you've got no patent you've got nothing to sell."

I don't think anyone has said that you should not get a patent. But how many millions of patents are on the record books with their sellers constantly wishing / promoting (avoiding the pitfalls of manufacturing, liability, Etc that everyone knows) and with only a miniscule few selling their way into considerable personal wealth? Meanwhile the Deep Pockets people and China are grinding away, scouring patent record books using their tremendous resources to find patents with the best business viability. Then the Deep Pockets are put to work finding ways to exploit patents with great potential without paying a cent, using things like reverse engineering and tweaking things just enough to to create or improve to a new patent, which is basically a legal similar copycat of the existing patent...


"It's all about having an exit plan. Investors like patents. It's the first question they ask."

Yes, and and investors don't care about the history, or the original inventor, or any other details about the patent itself, only $$$$.

 

The prop on the Manta 5 XE-1 hybrid electric hydrofoil doesn't look very large ( certainly not 22" in diameter) and that might give some General Clues as to what kind of prop to look for? I would think that a severe(maybe multi-stage) gear down would be required for an electric motor to drive a 22" propeller at planing speeds for a small lightweight boat, as with your given specs?

 

It seems to me that this idea doesn't even get past the back of an envelope stage.

Planing takes too much damn energy. And I don't see any way around it.

I find your discussion on patents far more interesting. The patent system in The US has evolved to the point of being ridiculous. It is almost as stupid as the copyright system.

I suppose this is why actual innovation here seems to have died out. Real innovators have little incentive (unless they're already stupid rich). Now, it's a contest to see who can afford the best legal team and pay for them the longest.

So now the real innovators are lucky to get a pat on the back, while the corporate bosses they work for get to enjoy the profits, while producing nothing of value themselves. Great work if you can get it.

A fairer contest would be to force the deeper pockets to contribute toward the poorer party they're litigating against, so the poorer party has half a chance.

I used to joke that the TV remote has probably killed more people than hand guns have. They allow one to lay on the couch and change channels incessently. All the exercise one misses by not getting off one's duff to do it, leads one further down the path to heart disease.

I thought of a solution which I called the TVciser. One would have to turn a crank to produce 75 W, or the TV would shut off. And there would be one crank per watcher.

Sports fans would become almost as healthy as the athletes themselves. But nobody would buy it.

The 75 W does nothing to power the TV. it just keeps a breaker open that will turn off the TV if closed.

Your idea seems similar to this scheme.

 

Whilst this hybrid electric/human powered boat idea may or may not work, I don't quite understand what is patentable here, or needs protecting by patent, is it the drive train ?

 

Yes it might be pointless metric (having patents) in practice of the operations but if that is the metric used in valuations then that is how one has to play. And investors care about what other investors are willing to pay for. So if their network uses patents as a currency/proof of valuable innovation then no point fighting it.

btw. The Manta looks pretty amazing. Before real reviews my assumption is that it takes a decent amount of work, half the clips the riders are of the seat cranking real hard. Then again batteries are slowly improving and even breakthroughs are possible.

 

When I interned at Nokia - young lifetime ago in 1999 - the folks were annoyed that someone had patented asymmetric loudspeaker outlet shape for phones. Basically any shape that was not symmetrical was covered by this patent. Now that was typical patent designed to fish fees and with any sort of rigorous work probably prior art would have existed. Many patens are total bs. and against the original idea of encouraging innovation.

 

Yes, all agreed, but what are you going to do if you come up with an idea, which after decades working in the field, running judging panels on marine innovation awards etc. you believe to be novel, never done before and potentially highly marketable?
Give up? Spend the rest of your life wondering 'what if?'

I'm aware of the numbers (vanishingly small) of inventors that do anything other than lose a stack of money. The odds are stacked heavily against and it's a real shame. I've got some ( commercial marine, Search and rescue, snow sports, defence industry) inventions too, also potentially patentable. Decided to go with this one first as a profile raising exercise, that might break even or lose me some money but will get the ball rolling and teach me a lot.

Because it's a leisure product, unlike anything that's been done before (and because I have a lot of contacts in yachting journalism and marine PR), it's going to be highly promoted (dare I even say hyped!) once I'm ready for it to be. It's ultimately a very low environmental impact boat that's likely to be convenient and pleasurable to own and use, so as we reach the end of COP26, we can safely say its time is probably now.

In terms of what's patentable about it, it's other aspects of the concept, definitely not mentioned here or anywhere else.

Obviously the general concept of a pedal assist electric boat has extensive prior art. As mentioned there's the Manta on the market now, quite apart from anything else that's gone before. It's the other elements of my design that really help it work, make it durable ( for a 50 kg powerboat!) desirable and easy for people who might not have owned a boat before to own and use.

I'm not decided on patenting yet. It's a big outlay. I might build prototypes to an impressive quality ( that looks to some like a production item), market it to hell and back, launch on a crowd funding site and get development or even limited production run funds quickly that way before it gets copied ( if it's any good it will get copied very quickly. That's priced in- nothing you can do about that nowadays). Crowd funding is another viable model these days, but not something I know as much about yet. If I go for crowd funding, you'll hear all about it on here (and elsewhere) much sooner!

I'd love to tell you all what it is and what it does and how it does it, because at the moment I know I come across as a total dreamer and time waster, and there's been more than a few of those on here over the years! It's got 10 features or USPs never done before on a production boat of this size. Some products sell OK with just one USP.

It's just too easy to do for someone set up for this sort of thing. Ningbo Vicking could probably get one on the market in a month, it's going to take me a couple of years just to get a decent prototype together!

 

The Manta prop looks custom, well done, and NOT efficiency focused. It looks to me like they are using a stock volume production E-bike electric assist in their own sealed package. This likely dictated the RPM and torque. They were short on torque, but had plenty of power. The smaller diameter four blade prop is lower stress which allows it to be plastic injection molded -very cheap to produce and good profit on a consumable, easily damaged part.
I presume Jakee will come to the same solution -in low to moderate volume it is important to minimize tooling for custom parts. He might have it a little easier because his craft won't sink without strong thrust from zero velocity.

 

IP protection is a massive issue that nobody here is going to change. I have allot to say about it but honestly I am already completely bored and unimpressed with the progress. Jakeee has been warned and his reply is he knows what he is doing -lets get back to boat design. Jakeee can get a provisional patent for a few hundred bucks. That will buy him a year to develop a product and his claims for a utility patent.
To design the prop you need the drag characteristics of the craft and the torque characteristics of the drive.

 

Indeed, the patent side is not why I follow a boat forum. There are some questions that can be answered just from the numbers provided.

George Crouch, early in the last century empirically determined that the Hickman Sea Sled hull form was, by a huge margin, the most efficient planing form when it came to very poor power to weight ratios. He felt that a sled could successfully get up on the plane at 100 pounds per horsepower, while the next best form might manage 45 pounds per horsepower.

To uplift these barbarian numbers to civilization, your 200kg assembly will need roughly 3.4kW net to have the slightest chance of planing. All discussion must start from there. Prop size, rpm, shaft, everything else.

 

Were I to attempt a pedal assist electric boat I'd do it differently to an E bike. To avoid complex gearing requirements to power with pedals at 60-90 rpm and an electric motor at 1000s of rpm I'd use an electric only drive system and a pedal powered battery charger to give back some energy. This way you could also afford to use a small battery like an E bike Li ion to save weight.
It sounds to me like the OP is at the research stage, not at the design stage. You need to get something on the water to develop. I know my pedal powered dinghy is a simpler affair but it only took 6 weeks to build to a testing stage. 4 months after that I had achieved my design aims. 3 months after that I had a robust little boat that has already covered 60 miles. I now expect the next 60 miles to be trouble free. I've written a few blog posts about it. https://mountainbiker.online/2021/10/26/cross-training/

 

Yes, the manta prop looks a little lower aspect than optimal to me.
But it's the same issue I will have. Increase the diameter and you increase the draught and prop fragility.
Same goes with skeg. You can put a skeg in front of the prop to protect it a little, but there's a drag cost to that.
I'm thinking go for no skeg quick release prop connector, high aspect two blader and supply a spare prop with the boat , recommend they carry a spare at all times, and sell owners lots of replacement props. That way it can be an efficient higher aspect design.

The Manta, being a foiler has a pretty deep draft for its size as it is, I guess they didn't want to make it any deeper than they could get away with

 

I'm not sure I buy this 3.4kW net number. Plus it's a 150 kg assembly, not 200.

In the land I still inhabit of 2 stroke outboards, 3.5 kW net is probably about a 6hp engine (depending on manufacturer).

But I can get into a 3 m, roughly flat bottomed, but fairly inefficient curved sided inflatable, put the old Johnson 4 ( bought 1982- still going strong) on the transom and plane at about 12 mph. It is not likely to be producing as much as 3.5 KW. Sorry if this is a bit unscientific, but 3.5 does not sound right to me.

Coincidentally, if the sea sled is what I think I remember it as, it's a big concave up front tapering down to a smaller concave at the transom, which is quite similar to the inflatable dinghy with a fabric floor that I was just talking about. My design is quite different from either of these.

Outside of this, as I said ebike/ escooter motors go commonly, and cheaply up to around 6 kw then they start to be moped motors, and at this level it's not going to be any kind of pedal ' assist'.