new kayak design took first place London Boat Show 2008

[Guest625101138]

Ken
I think the other images give a false impression of the size. I have placed a man on board to help scale it. This guy is big - maybe 90kg and 6ft tall.

Rick W.

[kengrome]

Aah, you said 4 meters above but I was thinking 5. Your new picture makes it clear the boat's not 5 meters long!

Your boat looks really nice by the way. It's only 3 feet longer than John's existing boat so maybe this one would actually fall into his updated performance requirements.

Edit: What's the displacement and draft at the waterline shown?

[Guest625101138]

Originally Posted by kengrome

.......

Edit: What's the displacement and draft at the waterline shown?

The displacement is 120kg and the draft is 150mm. From memory the WL beam of the main hull is 350mm. The boat is 1m overall beam.

Rick W.

[john zimmerlee]

Wow, you guys really know your stuff!
Thanks for all the drawing and comments.
Hands-free operation is the main focus. Shallow water operation is a close second. I have explored shrouded props. THought that would be very efficient. What I found was that smaller props didn't work very well; the prop needed to be an expensive fan type; if the kort nozzle was designed correctly, reverse was inefficient; weeds were a real problem; the depth required was too significant; and the propulsion was more like jetdrive, which didn't reverse quickly. Then I ditched the kort nozzle and created a tunnel in the hull that sloped down at each end. My thought was the water would be pressurized when it went up into the tunnel, lessening cavitation.

That was wrong. Cavitation was obnoxious. Performance was slow.

When I finally gave up on kort nozzles and lifting water up into tunnels, the performance increased by 25%.

Augers have surface area which grip the water for rapid turns and quick reversals. Simple augers work equally well forward and backwards. Props lose two-thirds of their performance in reverse.

I think the hull needs rocker. The bow and stern have rounded bottom edges which could be narrower. I'm thinking that the bow wants to rise while underway but the bouyancy of the stern is making it dig in.

The prototype has been butchered so many times for modifications, it is beginning to look very ratty!

John
Stream Dancer

[kengrome]

John, from your explanation it seems the augers are the best solution for your boat.

If speed is not one of your customer's big concerns (and I suspect it is not) you're probably better off keeping the hull as-is, and lowering the top speed of the augers if you don't want it to make a bow wave.

In fact, I think a plain old garvey or john boat hull would be a winner with his drive system in it!

I said this in an earlier post and I still think you should create a second model based on a jonboat instead of modifying your existing design. Jonboats have universal appeal. Several people can ride in them easily and comfortably. They would be cheaper to manufacture as well. A jonboat will give the boat a much shallower draft too, and you said this is your second most important goal.

Or if you really want your second model to be faster instead of shallower -- and not push up a bow wave -- just use Rick's design for your second model, then make the jonboat your third commercial hull.

I think the hull needs rocker. The bow and stern have rounded bottom edges which could be narrower. I'm thinking that the bow wants to rise while underway but the bouyancy of the stern is making it dig in.

Instead of trying to modify your current design, why not start from scratch? Adding rocker will shorten the water line and deepen the draft -- not exactly in line with your stated priorities.

I think your drive system is the real innovation here, and you should produce a number of different models with your drive system included. Then buyers will have a choice of several dramatically different boats -- all with the same drive system -- rather than another 'slightly improved' version of the same hull you're already making.

Thinking as a potential buyer, I would prefer a choice of different hull designs ... and I would go for the simple jonboat model regardless of the fact that it won't be as efficient as yours or Rick's designs. Why? Because it can carry my wife and son! You seem to be limiting yourself to one-person boats when a multi-person boat might actually sell better ... and a multi-person boat with a flat bottom will still have the shallow draft you're seeking, even when two or three people are in it.

Then again, this is only one man's opinion, others may have different priorities ...

[john zimmerlee]

Thanks, Kenneth!
I've built ten prototypes . . . and modified each one about a dozen times.
I'm getting tired of building new hulls!
Surely, there is somebody out there who will take over this project.
Can't wait to find that person or company,

John

[Gilbert]

Congratulations John.
I saw one of your models a couple of years ago on the web. I thought it was about perfect. I think your biggest market is with people who are not especially agile, maybe up in years where they can't row or paddle for some reason, but just want to get out on the water and snoop around. Your shallow, wide stable model that doesn't go very fast seems perfect.
You should be thinking of market research instead of new models it seems to me.

[john zimmerlee]

Gilbert, Ken, Rick, and all who have contributed:

I'm 59 years old. I don't have it in me to start a new business or even to keep building prototypes. I have a good idea and a patent pending. I've spent $119,000 proving that a lot of stuff doesn't work. Gosh, it I had just known 3 years ago what I now know today, I could have saved $100,000.

I just can't afford any more education!

John
Stream Dancer

[charmc]

Originally Posted by john zimmerlee

Now that I've won the concept award, I need help cleaning up the design of Stream Dancer.

This hands-free electric powered fishing kayak is controlled solely by your feet and operates in 6 inches of water without harming fragile underwater environments. Each heel rests in a sliding foot control which has linear potentiometers inputting pulse width modulation speed controllers which vary power to each of two submersible motors on either side of the kayak's centerline. The motors drive augers instead of props for less cavitation and stronger bite in the water, resulting in powerful turns and quick change in direction.

Stream Dancer's hull is now 10 ft long and about 38" wide. It's currently a tri-hull in the middle and kayak-like at each end. It seems to plough at high speed which leads me to believe I'm overspeeding the hull's max speed.

Four major kayak manufacturers have expressed interest but none can take on a new project this year. Guess I'm on my own to figure this out.

Appreciate your help,

John Zimmerlee
770-565-4420

John,

First, congratulations! You've taken a good idea and put your money where your mouth is, perservering through prototype construction. An international design award is something few small boat designers ever achieve.

You've had some good advice here. If I were you, I'd forget worrying about speed. From your video you have more than enough speed now. Reducing power a bit would reduce the bow wave/plowing and improve battery life without compromising current speed or manueverability.

The catamaran idea you have would make a good second model, but no need to develop it yet. IMHO, you have a saleable model now. Concentrate on marketing what you have. Once the money starts to come in, introducing a second model like the cat (different enough to attract new buyers without taking sales from the first model) should increase sales.

Keep at it. One problem now is the current shaky business climate; mfrs are probably reluctant to invest money, or may be having problems getting financing. On the other hand, your little boat is economical and environmentally friendly, which should make it very attractive to many buyers in the coming years.

No design will be perfect. I'm not criticizing any of the suggestions here, they are all valid. You've put a lot of yourself and your money to get this far, however, and I believe you have a saleable product now. I'd suggest you focus on marketing what you have. Sooner or later you'll find the right fit and you'll get the boat to the mass sales phase. Then you can decide if you want to revise it, introduce a second model, or sell out for the big bucks. That will be a pleasant decision.

[kengrome]

Hi John,

Here are some renderings of the type of boat I was thinking about when I suggested a 'jonboat'. I made this boat 7.8 feet long and 3.8 feet wide and 1.3 feet tall -- the perfect size to be shipped in a plywood crate with full sheets for the top and bottom and with 18 inch tall sides.

I figured 180 pounds for the boat weight and only 70 pounds for the smallest person to operate the boat. A 70 pound person will bring the boat down to its minimum draft of 6 inches ...

This boat is rather unusual. We usually want most boats that serve this type of purpose to float as high as possible, thus giving us the lowest possible draft and the most freeboard. But this boat has its own propulsion system built in, and it is not adjustable. This means the boat *must* sink into the water at least 6 inches -- even with the lightest person aboard -- or the augers will ventilate and be noisy and inefficient. At the same time the boat should carry several hundred pounds if asked to, without being in danger of swamping or taking on water.

The flat bottom of this boat, located 3 inches above the bottom of the sides, allows both light and heavy loading options with a very simple hull shape:

70 pound payload at 6 inches draft
440 pound payload at 9 inches draft

It also provides a clear and unobstructed flat bottom in the middle of the boat which makes passenger movement very easy and maximizes safety when moving around. The full wrap-around decks add strength and make the boat super-easy to get into and out of at any angle, too. The side decks are 10 inches wide and the end decks are 18 inches.

The waterlines shown in these drawings are at 6, 7, 8 and 9 inches. Freeboard at the heaviest loading is still 6+ inches if the boat is built with a deck and coaming as shown in one of these images. Everything looks smooth and curvy in these renderings because I designed this boat for roto-molded construction. This hull could very well be done in one piece.

Basically I ignored the appearance of the boat in favor of a relatively efficient design, given the dimensional constraints described earlier, and this is what I came up with. My thought here is that this shorter and wider boat:

1- will feel even more stable since it is nearly 4 feet wide;
2- fits into the back of a pickup truck more easily than a longer boat;
3- can still support one person very easily even though it is 2 feet shorter;
4- will maneuver more quickly and easily in tight spots on the water;
5- can comfortably carry a passenger on each end deck if/when the need arises; and ...
6- will easily fit into a cheap plywood crate for exceptional shipping protection.

[john zimmerlee]

Very Impressive, Ken!
Wished I had your talent and abilities!
Now, do you have a couple hundred grand to get into production?

John

[kengrome]

John,

The software draws the pretty pictures, I just tell it what to draw ...

I think you could be selling these boats and taking orders for more by the end of the year for a total investment of say $25,000. If I were going to approach this project on a low budget basis I would:

1- build a set of female molds for the one model you prefer
2- have the first few boats built in fiberglass and resin
3- if made overseas, have them shipped to you
4- install the augers, motors, controls, seats, etc.
5- start selling them online from your website
6- start taking the boats to dealers and shows

There's an American boat designer/builder living overseas in the Philippines who would probably enjoy building the molds and producing the first batch of production fiberglass boats for you too ...