Cheap to run, cheap to build electro plywood cruiser ?

[ASM]

Hello all,

I have been a member for a while now on this forum and have read many threads with interest. After substracting/consuming a lot of the (wise) information from this forum and designers sites, I have come up with a simple plywood cored, electro driven inland cruising boat for family/weekend use.

It is roughly 8 m long, 2.5 m wide, with a keel box to hold the batteries and motor. The salon top can be covered in solar panels, the big side windows aft could be of the opening type like in cars (manually of course ! no powerrrr).

Since I am no naval architect at all, could you give me some usefull feadback on the initial sketches and see where I made huge mistakes or if I am on the right track ? I am planning to build a 1:10 scale model just to see if it floats and its stabililty.

Thanks !

[Guest625101138]

What do you want to carry - displacement?
What speed do you want to travel at?
What range are you hoping for?
What conditions do you intend to operate in?

The design has merit. It may be possible to do better.

It is worthwhile building a model but it pays to do a bit more design first. Most important thing is to have a realistic displacement.

Rick W.

[ASM]

Rick

To be used as a day cruiser/weekender, inland waterways, maybe occasionally along coast line, but that option falls if that means to much adjustments or changes.

Approx weight on board: 500 kg (6 persons + light luggage)

Hull design speed (~7.5 knots ?) with a little margin for upstream, 'rough' water.
Range would be approx. 6 hours of running at 6 knots or so, solar panels to give a bit of extra range and ppower on board for electrocnics.

Displacement empty: 2 tons ( I do not know if that is possible for this sort of construction, I can imagine that the superstructure can be made from foam cored panel, which in combination with batteries in keel keeps te cog nicely low and therfor a stable boat)

Conditions, mild, it's a family nice wheather boat....

Straight shaftline, propeller surrounded by a steerable nozzle.

[Knut Sand]

I had an aricle lying around somewhere, believe it was in the Wooden boat magazine, Think it was on the frontpage also. May be a little over a year ago, or so? I'll try to look around for it. They had an article about a electric boat like that, trailerable, beam approx 7-8 feet maybe, long sleek and narrow, ply design(?) epoxy sheated, it was quite ok looking also. Maybe some other will remember this?

[Guest625101138]

I did a rendering of the hull based on a somewhat different underbody that I think would give good efficiency at 6kts for the other constraints specified. The hull displaces 2.5 tonne and is 8.4m long.

With a 14" 3-bladed prop, the hull shown would require 2.5kW to do 6kts but power rises steeply above that speed. It takes 10kW to do 7.5kts.

I believe a two tonne boat would not be difficult to achieve. If you are considering composite construction for deck then why not use for the rest.

Using VRLA batteries you will get say 20kWh for 500kg and this is the size you need to get fair battery efficiency at 6kts. Would have a range of around 45nm.

If you are happy to plod along at 5kts then range goes out to about 120nm.

An 8m boat of this beam and displacement will start to makes waves above 5kts and that takes energy.

If you want to do 6kts efficiently then you need longer hulls - say 10m or go for a catamaran.

This was the first pass so it may be possible to get better.

With things like this I normally start with the most efficient hull for the speed and displacement without any constraint and then decide what each feature costs in terms of performance. For example the optimum 2.5t hull will require 600W to do 6kts with a good prop.

Rick W.

[ASM]

Rick,

wauw you'r quick, thank s for this very impressive answer. As I saw your comments on several othe items ont his forum and your website, I kinda hoped you would be the one to reply........ is this your preffesion or are you just a big enthousiast ?

Will it be a big advantage to reduce the weight by 0.5 t ? and reducing the keel box in width ? I guess the waterflow towards the prop becomes more efficient then and together with a thrusttube around teh prop it should give some more efficiency, thus pushing the power graph a bit upwards in speed ?

Would it be very bold to send you the hull sections as in the attached JPEG with my thread, or do you consider the minimal differences of minor importance ? (so with a little bit of optimization on the hull, one expects an improvement, but the figures as calculated still stand and might end up with a little more power reserve, so in fact a worse case scenario ?)

I understand your philosophy, and I already started with a narrower hull, but considered space and ease of building (so relative square flat sections) important to sacrifice in performance.

Another thing I do not have the knowledge for is the situation that the 5 kts is a good optiomal cruising speed, but what happens to the power requirement when you run in a very strong countercurrent or wind ? Does it rise exponential ?

Thanks again...

[Knut Sand]

Hi

Impressed by the details given by Rick here.

The atricle in the Magazine was WoodenBoat, August 2005, not a year ago then... (The speed of time.....Ok, lets face it, all... we have to live when we do it, cos' when we're dead, we're gonna be dead for a long time).

Boats name is Nomad III, Article was "Considerations for a sun-powered cruiser".

Link here: http://www.duckflatwoodenboats.com/mainpages/mundoo.php

[ASM]

HI Knut

Thanks for the link, I had that one for 2 years now, also one of the inspirations and a proof that it is possible. I feel electric boating will become big in the years to come, and in The Netherlands where we have 14 million people and recent studies showed 1 in 10 own a boat of some sort..... and since we are a cheapcheap type of persons, the diesel fuel price will be painfull. We also have much more displacement craft compared to f.i. US so the potential for electric boats is big.

The downside with electric craft so far is the lack of 'sexyness', the ones available over here are scarce or or just plain ugly..... or are re-engined diesel ones, so bad publicity for the electric propulsion since they were not designed for such a propusion in the first place (WEIGHT !!)

BUt, there are some initial step in the right direction, look at: http://www.czeers.com/czeers.html

you see my point of view to devellop and electric family vessel ? Just for myself, but who knows if people are interested.....

[Guest625101138]

I could not resist looking at something more like the optimum hull based on the concept.

The attached is 10.5m long. It will require about 700W to do 6kts. So a large improvement over the other one. Hitting 7.5kts requires only 1.5kW.

The hull is effectively a trimaran. I expect performance would drop considerably in heavy weather because the side wings would be submerged quite a lot.

It is not all that different to what you drew initially.

The difference with this second one to the first one is that it will rely on the outboard hull for stability. However sitting 500kg of batteries in the keel will certainly help to keep it upright.

I would say building a model of this will be interesting. You might get a lot of interested folk.

Rick W.

[Guest625101138]

Rick,

wauw you'r quick, thank s for this very impressive answer. As I saw your comments on several othe items ont his forum and your website, I kinda hoped you would be the one to reply........ is this your preffesion or are you just a big enthousiast ?

Will it be a big advantage to reduce the weight by 0.5 t ? and reducing the keel box in width ? I guess the waterflow towards the prop becomes more efficient then and together with a thrusttube around teh prop it should give some more efficiency, thus pushing the power graph a bit upwards in speed ?

Would it be very bold to send you the hull sections as in the attached JPEG with my thread, or do you consider the minimal differences of minor importance ? (so with a little bit of optimization on the hull, one expects an improvement, but the figures as calculated still stand and might end up with a little more power reserve, so in fact a worse case scenario ?)

I understand your philosophy, and I already started with a narrower hull, but considered space and ease of building (so relative square flat sections) important to sacrifice in performance.

Another thing I do not have the knowledge for is the situation that the 5 kts is a good optiomal cruising speed, but what happens to the power requirement when you run in a very strong countercurrent or wind ? Does it rise exponential ?

Thanks again...

Boating is my hobby.

You should be able to get reasonable section drawing off the lineplan if you want them.

At this stage I think it is still an idea in development.

The length is really the big factor from an efficiency perspective. WEight comes into it but if you can stay around hull speed or below then there are big benefits.

The design has huge potential. It is sort of taking the Atkin hull another step.

I am not certain about the seaworthiness for heavy weather but once you stick 500kg in the bottom of a small boat it really stiffens it up.

If you are serious about the model I will do more work on it. You should be able to get Delftship and I can give you the file so you can play with it.

As you can see if you go longer you can reduce power required and therefore battery weight.

I also think 6kts is a good cruise speed.

If you determine what are really hard constraints then it can be pushed and pulled to suit.

Rick W.

[ASM]

Rick
Thanks for all your input and I also think it has huge potential as this kind of electric vessel is not on the market at the moment and suits a big crowd needs.

The trimaran concept is already in (sort of) devellopment:
http://www.tcdesign.co.nz/bt_featherline.htm

Though the website is not up yet for the featherline brnad, it is under construction for almost 1.5 years now....

I will be on a short holiday this weekend and thin kthings over, will come back early next week on this !

[messabout]

Rick:
I can see but little advantage in doing the under body as a faux trimaran. Much simpler to let it be a box keel with flat or slight deadrise outer section. I reckon it ought to have some aft rocker to get the transom reasonably clear of the water. I'd also pinch the transom in a bit. In a chop or when traversing wakes the aft corner of the boat will dig in such a way as to make temporary drag. A narrower transom is also structurally stronger as well as lighter. Keep the ends of this boat as light as is practical.

The advantage of the sections that you have drawn are structural. That is to say that the width of the flat sections are smaller and will require less framing than a wider flat section. On the other hand the larger number of corners (chines) will increase eddymaking and contribute to drag. In a boat of this sort we are trying to keep wetted surface and drag to a minimum.

My attic is the resting place of a model of this very type. The model is about one meter long and was propelled by an electric motor with radio control. Care was given to maintain similitude as regards displacement. The model performed very well at S/L ratios of less than about 1.2. Pressing the speed much beyond that caused a big wave train, clumsy behavior and rapidly drained batteries.

[Guest625101138]

Rick:
I can see but little advantage in doing the under body as a faux trimaran. Much simpler to let it be a box keel with flat or slight deadrise outer section. I reckon it ought to have some aft rocker to get the transom reasonably clear of the water. I'd also pinch the transom in a bit. In a chop or when traversing wakes the aft corner of the boat will dig in such a way as to make temporary drag. A narrower transom is also structurally stronger as well as lighter. Keep the ends of this boat as light as is practical.

The advantage of the sections that you have drawn are structural. That is to say that the width of the flat sections are smaller and will require less framing than a wider flat section. On the other hand the larger number of corners (chines) will increase eddymaking and contribute to drag. In a boat of this sort we are trying to keep wetted surface and drag to a minimum.

My attic is the resting place of a model of this very type. The model is about one meter long and was propelled by an electric motor with radio control. Care was given to maintain similitude as regards displacement. The model performed very well at S/L ratios of less than about 1.2. Pressing the speed much beyond that caused a big wave train, clumsy behavior and rapidly drained batteries.

This is in early stages. It was 10minutes of work. I am sure it can be improved. Looking at the lineplan I can see 3 changes already that would make it easier to build and one possibility to reduce the ama drag.

Would like to see a photo of your model and more comments on how it performed. Even better would be a video clip of it at economic speed and also with wave making.

Rick W.

[rwatson]

That design takes me straight to Phil Bolger - even looks like the boat he designed
Check out

http://www.ace.net.au/schooner/fms.htm

You can get the plans for $400 at

Phil Bolger,
P.O. Box 1209
Gloucester MA 01930

[afrhydro]

i built this boat for electric power plant
but I'm still working the bugs out
so I'm testing it with gas motors now

for me its already to go just battery money and controller money is my problem

[Guest625101138]

Here is the ASM10 with canopy, prop, rudder and pilot.

Would be worthwhile building a model of this. I can run performance data on the model.

If you select a motor that has efficiency data it would be reasonably accurate to do performance checks with low cost multimeter. I suggest you go to a model of robust size. You want a displacement around 5kg to give you something to work with that is robust. So suggest about 1/8th scale. This will make the model around 1.2m long.


Rick W.

[rwatson]

Check out the 'Electic Mundoo' - an already designed, proven production design, with battery skeg and all the internal specifications complete at

http://www.duckflatwoodenboats.com/mainpages/mundoo.php

in plywood, trailerable, liveaboard size. Seems to have most of what you need there.

[kengrome]

messabout, I think Rick based his design on the Atkin tunnel-stern Seabright skiffs. These were very economical hulls at low end planing speeds, but this boat will never plane even at low speeds. Therefore I think the original Seabright skiffs might be a better starting point since they were designed for slower displacements speeds, and in fact evolved more directly from sailing boats. I might suggest Spermaceti:

http://www.boat-links.com/Atkinco/Utilities/images/Spermaceti-1.gif

... or perhaps Sergeant Faunce:

http://www.boat-links.com/Atkinco/Utilities/images/SergeantFaunce-2.gif

... but built using lighter construction materials and techniques than Atkin specifies of course.

I think Knut's suggestion of "Mundoo II - Electric" from Duck Flats would be a nice boat in protected waters, and I think this is actually the kind of use ASM described:

http://www.duckflatwoodenboats.com/mundoo/pics/large/M2ElecricPlan.jpg

http://www.duckflatwoodenboats.com/mundoo/pics/large/Mundoo2Launching2.jpg

rwatson, I think Bolger's Fast MotorSailer would use gobs of power since it is a planing power boat design. It's a nice boat but not particularly well suited to electric power.

[ASM]

Hee guys,

Thanks for all the comments.

To Rwatson: the Bolger's fast motorsailer does have a lot of resemblense but, as kengrome says, that is a planning design wich does not plane with 70 HP ! Though since it was designed as a sailing boat, it might run efficiently at low speed too...

The Duck flat wooden boat was, as said, also part of my finds on the net which gave me the idea and confidence that what I wanted was possible. I have however, like Rick stated, used the Atkin tunnel-stern Seabright skiffs design in the link as well.

Basically it looks a lot like the 'trimaran' Rick has put together. I had envisioned it a little different, not much. As can be seen in my original post, I had blunt sharp bow, though the underwater one could be as shown by Rick if that gives better efficiency. In fact the bow both under and above water is just like a piece of pie, so also no odd double twist for plywood. The sheer (?) would start above waterline and from flat bar twist into a slightly inverted V shape, like the Atkin's. So in fact my two 'sponsoons' are triangular shaped because of this slight V. Another option would be, and much easier to make, a flat section like Rick drawn, but make the two 'sponsoons' out of pre-cut H80 foam which one stick under the flat bottom, then glass it over with the rest. In my 'ideal' non naval architect world, I see this as a easier to build and a positive influence on pushing the water towards the propeller, thus increasing its performance.

Rick, thanks again for your work, I see you have worked on it again and made it more and more realistic. The problem I have as a beginner, are the V-curved shapes of the bow. Attached I have sketched something I think is easier to make and a little more in line with my original design, though it might be stupid and downgrading the performance and endurance.

Just for my understanding, the first 'tri' you drawn, the grey areas are the wetted areas. These are the surfaces needed to float this boat at the given displacement right ? And can I assume that the position if these 3 areas is the base for a good weight distribution on the water, so moving the outer contact surfaces aftwards will effect the longitunidal stabililty ? So in other words, by increaing the beam and keeping the same weight and location of the wetted areas, one could have a bigger beam without too much influence on the rest ? (I guess the keel hull needs to be the same and therefor the bow through the water does not change in width, thus not decreasing performance ?

[Guest625101138]

ASM
The ASM10 is a monohull straight from Godzilla with a little licence to reduce length and make it developable. The performance numbers are for 80% efficiency prop and the developable hull.

I have attached the lineplan for the revised ASM10. This would be very easy to build using flat pack construction. The strip that forms the flare coming up from under the side wings of the hull may need to be laid up with only one side glassed to enable the curve and then finished off.

There are subtle diiferences from the original lineplan plus more detail.

I am working on the bases that the outrigger hulls are just touching the water so do not contribute appreciably to drag. This is quite different to the Atkin hull - much narrower centre hull. Also the submerged wings on the Duckflat boats would add considerably more wetted surface.

I have not done any work on the ideal placement and shape of the outriggers. Also I have not checked the stability curve. You may require wider outriggers to give good initial stiffness.

Rick W.

The

[kengrome]

Hi Rick,

At first I couldn't understand the benefits of going with such low wing decks and amas that only just touch the water, but now I think there are good reasons for it ... although higher wingdecks would still be an advantage.

If you're using FreeShip 2.6 can you send me your .fbm file? Or if you're using a later version or Delftship can you export it as .fef then send it to me? I would like to join in this discussion with an example or two based on your work, and it will save me some time if I can avoid recreating your hull from scratch ... :)

[kengrome]

And Rick, a couple of questions:

1- What is the purpose of the rocker forward in the box keel? Is this to provide some lift to the hull, or to aid in beaching ability? The reason I ask is because it is all underwater, so it seems the forward box keel might be more efficient as a purely flat bottom with no rocker forward and instead having a vertical knife edge bow. Wouldn't this reduce turbulence?

2- Why didn't you make the aft end of the box keel a knife-edge instead of pinching it out to nothing? Wouldn't a knife-edged aft end better support the prop shaft and streamline the flow better back there as well?

3- I may have been mistaken and I'm sure you know more about this than I do given your extensive experience with long slim hulls, but I've been under the impression that when a double-ended hull is asymmetrically wider aft than forward, it is more easily driven ... yet in the rendered images your box keel looks wider forward than aft. Is this just an optical illusion due to the fact that the box keel pinches out and basically 'disappears' aft? Or is it really asymmetrically wider forward and narrower aft?

[ASM]

Rick

as usual, thanks again for all your efforts, and as seen from the side, this model is indeed as easy to build as I had envisioned.

Wider outrigger, if needed, would contribute to increasing beam as well, a win-win situation ?

The questions raised by Kengrome, 1 and 2, are exactly the wording I was looking for, but again, I am no naval architect. As for item 3, I would say that like a waterdrop, the shape should be a bit ássymetrical to have a as much as possible on turbulent flow of water to the prop.... but I could be wrong.

Looking forward to your inout Kengrome and Rick, and see at which point it makes sense to start a model.

[Pericles]

A very interesting couple of pages, taking the design process a few good steps further than earlier threads on the subject of electric boats. The benefits of efficient power storage are not far off and in a couple of years or so we'll all be unshackled from the iniquitous prices now being charged for diesel fuel.

http://en.wikipedia.org/wiki/EEstor

The underwater lines at the stern of Narrow Boat Hadar nicely illustrate the second point Ken makes.

Perry

[ASM]

Pericles,

I have had this idea in my mind for years now and think the time has come to try it out, as said, the small yacht/ship building in the Netherlands is very traditional (steel mainly) and they are trying to re-engineer an existing design to run on electricity or they come up with ugly/silly looking crafts....

This is why I published my ideas, since I am no naval architect, they were just ideas from reading through a lot of designs and threads here. Once you can create a good looking electric inland (occasionally coastline) vessel which is moderate in price and cheap to run, you could be in for an exponential growth ! From what I saw on this site there are a lot of smart people on here who can contribute to improvements whilst maintaining most of the original (above waterline) design.

Me, I just want the thing to work always, easy to build, no hassle with diesel engines and smells and fun for the family ! And of course, being a Dutchman, cheap to run !

[Guest625101138]

Ken re ASM10
The rocker is the result of unconstrained length optimised for 6kts direct from Godzilla. It was longer but I chopped off a bit.

This hull is a lot more efficient than an Atkin.

I have not spent a lot of time on the stern. Remember it is not a tunnel hull. It is just a long slender hull with outriggers.

The strern treatment would be better suited to an outboard and you could knock 0.5m off the length.

My little Kelly/Mars drive would work well on this.

Rick

[kengrome]

The rocker is the result of unconstrained length optimised for 6kts direct from Godzilla. It was longer but I chopped off a bit.That's interesting because I figured a plumb bow on the box keel might be more efficient than the one shown ... but if the box keel's bow was not constrained in Godzilla then I guess it already has the most efficient shape. Interesting ...

Thanks for the file by the way. I will plug it into FreeShip 2.6 and do some mods so I can show you what I'm thinking about, assuming the power and internet are available during the current typhoon. Both were out this morning ... :(

[Guest625101138]

You will see with Godzilla that as a hull gets heavier the optimum tends to get longer with nice rocker providing length is unconstrained. If the length is constrained then the rocker goes flatter and ends get fuller.

Rick

[John in CR]

Considering waves and loads that aren't perfectly balanced or fixed for real world use, as opposed to conditions for competitive rowing, why isn't a catamaran the first choice when it comes to electric boats? I understand that transportability, boat slip or parking widths, and narrow canal use can preclude cats, but otherwise the extreme hull length to beam ratios and stability seem to make them the logical choice, at least from my noob perspective. Is it only that the maritime industry is stuck in tradition more than most, or are the reasons founded in hard science? Is the inherent increase in whetted surface truly so detrimental?

John

[ASM]

John

I have thought about a CAT for a long time as an option too, and I do agree they tend to have much more usable space. Downside is one needs two engines, so more costs though they can be downsized. OK fair, one engine COULD be possible but somehow seems 'odd' on a cat. A real trimaran would fix this with a centre hull engine. But hen comes in the fact that I am new in the boatbuilding, and going for cat or tri in the first go is a little bit too much. It is more complicated work to my mind and more materials and more space needed. Furthermore, birthing here in the Netherlands is not optimized for CAT's, that is, the width is limited or one comes into the big boat boxes and thus overpaying.

Actually the second design I did was just the hull as original posted x 2 , since I do not want high speeds or extreme condition cruising, it can be done I think.

Let's say it's on my list but as a second project perhaps.....

I fully agree a CAT can be more efficient for electric propulsion, but hey, as Rick calculated 1.5 kW for 7.5 kts.... how is that for efficiency ?

[FAST FRED]

"why isn't a catamaran the first choice when it comes to electric boats? "

For the same displacement twin hulls will have more immersed area than a single one.

Since electric boats are operated in displacement mode the surface area is more of a handy cap than higher speed wave making.

FF

[John in CR]

"why isn't a catamaran the first choice when it comes to electric boats? "

For the same displacement twin hulls will have more immersed area than a single one.

Since electric boats are operated in displacement mode the surface area is more of a handy cap than higher speed wave making.

FF

Fred,

I was under the impression that it wasn't that simple with whetted surface being only 1 component of efficiency through the water. It seems to me that once you factor in stability, a cat makes achieving far more efficient hull shapes for displacement vessels relatively easy. Modern ferry boats would be a prime example.

As ASM pointed out, berthing requirements seems to be the biggest strike against cats, though I would like to learn more about the particular handling characteristics through waves of different cat hull shapes.

John

[FAST FRED]

I was under the impression that it wasn't that simple with whetted surface being only 1 component of efficiency through the water.

At low speeds (not wave making) it IS the biggest concern

" I would like to learn more about the particular handling characteristics through waves of different cat hull shapes."

Cats go over , not through the waves , at least in the sizes we can afford, Ferries are different, far far heavier.

FF

[John in CR]

Cats go over , not through the waves , at least in the sizes we can afford, Ferries are different, far far heavier.

Fred,

We're definitely on different wavelengths. I'm not talking about a pontoon boat. My first electric will start with a sailing cat design that slices through waves like a monohull could only dream about.


ASM,

I'm sorry that my post has lead to off topic discussions, but after the initial design evolved into what is essentially a multihull boat, my thought is to just start there.

John

[Chris Ostlind]

Interesting discussion, guys, with lots of very stimulating ideas being put forth. Here's another take on this whole thing, albeit on a much bigger scale and for a much different end purpose.

"May 15, 2008 With naval battles on the high seas now virtually extinct for the U.S. armed forces, the navy's role has become more one of infantry invasion and airstrike support - and with this new role comes a need for vessels more suited to littoral (just offshore) operations. The initial order was placed back in 2005, and the first delivery, the U.S.S. Independence, has just been launched, a speedy trimaran with helicopter decks, a stealthy radar profile and a healthy array of arms. It's configurable to suit a wide array of littoral combat missions, including minesweeping, anti-submarine and surface combat support - and now that we've seen it in the flesh, it wouldn't look the least bit out of place soaring over the credits of a Star Wars movie.

The U.S.S. Independence is the first of a projected fleet of between 50 and 100 littoral combat ships (LCSs) the US Navy will be adding to their fleet over the coming years. Built on a well-proven Australian-designed trimaran platform from Austal, the LCS is fast, stealthy and well suited to a range of offshore combat support missions."

I was especially drawn to the shapes and the concept rather than the military aspects of this design, but it shows an uncanny resemblance to the craft being discussed on this thread.

[Chris Ostlind]

Directly tagging to the thread title of Cheap to Run, Cheap to Build... there was this bit which showed-up today in the news.

"Advancing a viable market for photovoltaic solar energy involves a balancing act between creating efficient solar cells and at the same time reducing the cost of the manufacturing process. Solar efficiency has been demonstrated to levels as high as 22% (a record set by SANYO last year), and although HelioVolt Corporation's latest announcements concern technology that is only delivering 12.2% conversion, the company has made great strides on the other side of the equation. Its proprietary FASST reactive transfer printing process has produced solar cells in a record setting six minutes, according to HelioVolt that's 10 to 100 times faster than current production of thin-film photovoltaics and could lead to manufacturing costs of less than $1 per watt.

Unlike the Sanyo crystalline silicon-style cells, the HelioVolt cells uses thin film technology based on Copper Indium Gallium Selenide (CIGS). It's worth noting that the solar conversion comparison - basically a ratio of the energy produced and the amount of sunlight hitting the surface of the cell - isn't exactly "apples and apples", and the 12.2% achieved by HelioVolt’s device is very efficient for thin film technology.

CIGS which offers significant cost savings for solar electricity installations by reducing the amount of material required to produce electricity from the sun, along with durability, a life-span equivalent to silicon and the ability to be manufactured in a printing process.

This last attribute means the FASST process can be used to print high efficiency, low-cost thin film material directly on glass substrates for solar modules OR onto an array of building products including steel, metal, glass and roofing tiles where it can be integrated into architecture as a type of "solar skin".

The company says the cost of less than $1 per watt that it is targeting with its thin film technology is, according to a study conducted by the U.S. National Renewable Energy Laboratory, the price point at which the photovoltaic market can compete with fossil fuels.

Dr. BJ Stanbery, CEO and founder of HelioVolt said that CIGS was already achieving the highest efficiencies of any thin film solar material in the lab. “The challenge of course is transferring that efficiency to a high throughput, high yield, low cost process capable of delivering gigawatts worth of quality commercial product,” he said."

With the large passive roof on this proposed design, this kind of solar cell development allows for the drive system for this proposed boat to be entirely electric and at a bargain price, to boot. Now we're talking energy efficiency, quiet service and reasonably low cost per mile/kilometer operating expense. It also doesn't hurt that the batteries held down low in the central hull pod will give the stability benefit that this boat needs.

ChrisO

[John in CR]

Chris,

Yes, that navy vessel is very much like the drawings. Maybe RickW will step back in and explain the advantages of that trimaran layout over a catamaran, since he plans to go that route too with his ocean going hybrid drive boat. eg What % reduction in whetted surface and/or efficiency can be gained?

I too am extremely excited about the prospects of solar and electric over the next 10-20yrs. Not only is PV coming around, but even more importantly big strides are being made in electricity storage. If the ceramic batteries / capacitors become a reality with almost unlimited service life, lower weight, and low cost abundant materials, electric drive becomes a no-brainer. The changes coming will make the computer revolution look puny.

John

[ASM]

The navy vessel indeed resembles my original design/thought.....

I am cusious if Kengrome has coma up with something from Rick's file.

As for the trimaran, I still have this little question in my mind, what if, leaving the weight equal, the outer floaters are a bit more outwards, so increasing the beam, and getting the flat surface in between the center keelbox and the outer floaters under a small angle to prevent direct pounding hits. Would this make sense and be possible without breaking any rules of physics ? I know one almost creates a full trimaran then, but that is not the goal since I want to keep the beams below let's say 3 m because of berthing.

In all, maintain more or less the original design looks, easy to build 'boxy' design, reasonably efficient, get some sort of trimaran underbody but not for the full width but for the sake of efficiency improvement. Would that be possible ?

Chris:

The market of solar power and power storage is indeed growing rapidly , I follow it by great interest, but there are a lot of reported 'overestimated' performances, because one would like to be the first to have the ' holy grale' in solar power or power storage.

[ASM]

Rick / Kengrome

I need to ask a favour, as I think you are both busy in the Atkins testmodels thread..... would one of you be able to help me out to a final scale model design, based on the one Rick created but with straight bow and straight chopped off aft keel section and the biggest beam possible keeping the same overal displacement and the two outside floaters in the right position for best stability ?

I have dowloaded Delftship, ran the file in there, but then I do not have a clue on how to proceed....

Is there also a possibility in there to project the individual panels on a flat plane so one could cut then out in the right shape from a plain sheet ?

Thanks !

[kengrome]

I am cusious if Kengrome has coma up with something from Rick's file.After seeing it and thinking about the entire boat concept for a while, I realized that Rick has done something unique and hard to match. My concept would simplify construction quite a bit, but it would also increase wetted surface area and reduce efficiency -- and I think efficiency is the more important goal -- so the bottom line here is that I stopped before I got started.

I have dowloaded Delftship, ran the file in there, but then I do not have a clue on how to proceed.Since it is Rick's original design I will leave it to him to decide how to proceed here.

Is there also a possibility in there to project the individual panels on a flat plane so one could cut then out in the right shape from a plain sheet ?Yes, FreeShip/DelftShip can "Develop plates" after you create a layer for each panel.

[Guest625101138]

I have been so intrigued by this idea that I took it a step further. I now have the ST12. This is an alternative concept to my current Solar_Wind boat.

I believe it would be very easy to build. It has not been faired out properly as there is better stuff than Delftship for this.

Like my solar wind boat, it has a removable bow - 4.5m long. This could be stowed inside for transport. The boat would be trailered backwards and the bow mounted before launching as it would be quite heavily loaded once in the water. A hollow bow section made from foam sandwich could be moved about by one person in a pinch.

It is intended for sandwich foam flat pack construction with displacement of 1200kg.

This boat would be extremely economical. Performance as follows:
6kts 570W
8kts 1.44kW
11.5kts 4.5kW

This is possible with the Mars motor I currently have. The intention would be to set it up as an outboard hanging off the stern but fairing into the main hull underwater to give clean exit.

It has good initial stability. Will self right if ever capsized. It has useful space. The shape is suited to light but strong construction.

ASM- As far as development goes using Delftship: I save the complete hull as a .part file in Delftship and then import the part repeatedly to cut it up into the developable sheets, one sheet per drawing layer, until I have the complete hull reproduced as developable layers. This hull would need about 11 layers to produce enough cut-outs for a model. It sounds lengthy but only takes an hour or so.

There is also a bit more work needed as the floor of the cabin encloses the main hull. It would have cut outs for stowing weighty items like batteries and water under the floor but within the main hull.

I will eventually do this but not this week as I am busy on holidays.

This is a more extreme version of the ASM10 but same overall concept. It is easier to construct. It has initial stability because the "V" shaped outboard hulls are already slightly immersed with no roll.

The trim would be achieved by placing the batteries forward of the windscreen in the middle hull against the bulkhead at 7.5m. That is where the bow section mounts. So, as noted above, bow section is 4.5m long.

Rick W.

[Guest625101138]

Chris,

Yes, that navy vessel is very much like the drawings. Maybe RickW will step back in and explain the advantages of that trimaran layout over a catamaran, since he plans to go that route too with his ocean going hybrid drive boat. eg What % reduction in whetted surface and/or efficiency can be gained?

I too am extremely excited about the prospects of solar and electric over the next 10-20yrs. Not only is PV coming around, but even more importantly big strides are being made in electricity storage. If the ceramic batteries / capacitors become a reality with almost unlimited service life, lower weight, and low cost abundant materials, electric drive becomes a no-brainer. The changes coming will make the computer revolution look puny.

John

John
If length is not constrained then a monohull will require about 40% less power than a catamaran of the same displacement. The difference in wetted surface is 26% for the same shape but once you optimise shape the benefit gets even greater.

By the time you make a monohull stable by using ballast or form stability the catamaran is often better. Trimarans have proven to be the best overall. Canting keels or other forms of movable ballast are now up there with trimarans.

Trimarans offer the low wetted surface of a monohull but the good form stability of a multihull. The idea is to have it operate on one hull if possible. With sailing tris this can be the ama in heavy air or the main hull in light air. With a sailing cat you can get it to sail on one hull but it is a knife edge. For a powered cat you always have both hulls near equally loaded.

Main problem with multihulls in my view is that they are usually not self righting. I believe this is essential for a boat under 40ft intended for use in the ocean. (I know this is debatable)

I have done a design review in the previous post showing the ASM10 concept taken even further - see ST12 attached. This looks to be a very efficient boat of usable proportions.

Rick W.

[ASM]

Rick

Did you enjoy your holidays ? or did your mind kept on running with new ideas ? The tri is very efficient indeed, good to see that it might be incorporated into your own plans ! Have you ever thought of participating in one of those solar boat challenges ? We have 2 overhere, time trials over inland waterways, with solar panels provided by jury and only solar power to run on. They now have added an extra rule that the vessel must have an overall 8 km/hr speed to participate...

Anyways, I would like to ask a favour, since Delftship is a unknow programm for me and by the time I have found out how to use it, I will be weeks ahead....

The ASM10 you entered in Delftship, I would like to fomulate that into a 'semi' final design to model in scale. I would however use a sharp bow and a sharp/straight keel end, let's say ending 30 cm before the transom. If the design would be limited to 9 m's, what width could I have with those outriggers, shaped like to ones one the tri ST12, with the 2000 kg limit for the vessel ? I think those triangular shaped ones with a sort of knife edge entry in the water will be more efficient and the surface area of additional floatation support will increase dramatically when the waterline rises)

thanks.... and sorry to ask all those Q's !

[Guest625101138]

ASM
I am still on holidays. I am in Canada this week. I spent Saturday in Seattle with a fellow HPBer trying out his Cadence pedal boat. These are production boats so very nice finsh. Here are photos and some very large video files:
http://snorlax.lampi.org/images/Lake%20Union%20RW%202008-05-24/index.html

I am heading to Calgary by car to do some tuning on a HPB that is a copy of my latest design. Some initial testing can be seen here:
http://www.adventuresofgreg.com/HPB/2008/05/good-test.html

I have thought about enetering the various solar challenges but my interest in these boats is a cruising boat for retirement.

I might have some time in Calgary to play with the ASM10. I am not entirely clear on what you want. I will redo the basic hull optimised for 6kts, displacement of 2000kg and overall length of 9m. I will produce the ASM9 based on this with the triangular stabilisers.

Delftship is free software that can be downloaded simply by registering on the site. I think you would find it rewarding to take some time to learn to use it. It is much easier to look at the designs when you can move them about in 3D. There are many people of this site who can provide assistance if you get to something you cannot understand.

Rick

[ASM]

Rick

Take your time, enjoy your holilday !! don't spoil it by doing computation stuff... nice design of the water peddle cycling power thingie... it seems to be very efficient.

I have attached a rough sketch of what I ment in mymail before, I hope it make sense, don't look at the dimensions, the are just red penstripes in windows paint.

It probably will be a mix of efficiency and looks, it would like ot keep the looks as close to the original, but efficient under water to a certain degree. So let's say a 5 kW engine on board, which means you don't have to go all the way down to 600 W for 6 knts... would be nice but... you see my point ?

Thanks again, enjoy your holidays and have some fun !

[Guest625101138]

ASM
I will be able to fiddle with the existing hull to get those changes.

The width change needs to be considered. If you intend to trailer it then the limit is probably 2.5m without a permit. Not sure of your road rules. Is this an issue? If not then specify what width you would like.

Also the idea with the stabilisers is to have them just kissing the water. I will set them so at design displacement the KMT is at 0.8m. This should be above the centre of gravity so it will sit level. When lightly loaded it might have initial flop when in really calm water but I doubt this would be a bother.

Rick

[ASM]

Rick

I guess 3 m would be a max beam, it is not intended to be trailered. I do not know if the 2000 kg displacement can be held if the width becomes too much since it will take material too !

[Guest625101138]

Rick

I guess 3 m would be a max beam, it is not intended to be trailered. I do not know if the 2000 kg displacement can be held if the width becomes too much since it will take material too !

ASM
You should consider composite flat pack construction. I am confident it could be built within 2000kg using this method using glass composite. I expect prices would be comprabable with marine ply construction maybe even cheaper.

Some of the curves are a little severe but this can be managed with single sided initial layup and then glassing the other side once in position.

Rick W

[ASM]

Rick

I am not at all familiar with flatapck composite panels, I know a bit of woodworking and have a good address for fair priced okoume plywood. Imight do a combination of both, so flat side above WL in composite and the cabin top as well, so the heavy parts as low as possible.

[Guest625101138]

Here is some stuff for the ASM9. It is a bit rough and would pay to make it from cardboard first to check the detail. I did not spend a lot of effort fairing.

The panels are scaled 40:1 and the stations are 20:1.

I am not in a position to check these. They are straight from Delftship.

Rick

[Guest625101138]

Second set.

Rick W.

[Guest625101138]

I should add that the floor in the aft section is full width. This is in keeping with the idea of flat pack construction. You cannot make frames that exactly follow the stations because the outriggers are formed from the side of the hull, the floor and the long thin piece I have called "outrigger"

Hope it makes sense. Send a photo if you mock it up in cardboard.

It needs a bulkhead to tie the front deck to the aft flooring. If you do this it will have good torsional rigidity. I have not done a cutout for this.

I have not recalculated the speed v power but it will not take much power to do 6 knots. The design displacement is around 2100kg. It will sit nice and steady with this displacement.

Rick W

[ASM]

Rick

Thanks again, this is excellent work. I have actually got about a dozen of file-boxes in 1 mm thick cardboard, so I might use that as skin and thin ply for frames. Will keep you updated !

Since I do know how to work with AutoCAD, would it be possible to send files in that format ? So I can scale and print to scale, so I just have to copy it 1:1 on the cardboard.

Sandor

[Guest625101138]

Delftship is much easier to use than autocad. Just download it and do your own developments to suit your scaling. It will take me a while now to produce plot files for each sheet.

I have attached the devlopable fbm file and a 3D autocad of the same thing. I have not used autocad for development so have no idea if that is possible.

Rick

[ASM]

Rick

It's getting the same message, but thanks again for all your effort. I have now Delftship, and exported the linesplan in AutoCAD, which I can use now to put interior, etc etc, into the vessel. I can also print the individual 1m sections to pin down on wood, making cut outs, or, finding someone who can precut them by CNC !

The power requirements etc, is that a function in Delftship too ?

[Guest625101138]

......
The power requirements etc, is that a function in Delftship too ?

Delftship will not give very reliable performance data from what I have looked at. I use Michlet and find it to be very close for slender hulls.

Rick W

[Pericles]

Couple of articles about electric power and an easily driven hull.:D :D :D
Page 56 in http://www.proboat-digital.com/proboat/20080607/
Sabdes 50-meter Axe-Bow. http://www.yachtforums.com/forums/future-yachts-concept-boats/9121-future-concept-sabdes-50m-axe-bow-superyacht.html

Regards.

Perry

[FAST FRED]

Rick, Looking at your great design it seems the displacement is almost all in the box keel and the sides simply give stability to the vessel at rest.

Could a bit of angle of attack on the bottom of the box keel give enough lift (like a water ski) to get the sides clear , removing their drag underway?

FF

[Guest625101138]

Rick, Looking at your great design it seems the displacement is almost all in the box keel and the sides simply give stability to the vessel at rest.

Could a bit of angle of attack on the bottom of the box keel give enough lift (like a water ski) to get the sides clear , removing their drag underway?

FF

Fred
The drag from the "outriggers" will be very low in calm conditions. In fact if the boat is unloaded it could flop from one side to the other if the trim is perfect and there are no waves. I doubt that this would be noticeable problem as it only flops a few inches.

At design displacement the KMT is similar to the Atkin style hull I did for you. Difference with the ASM type hull is that the stability increases significantly once it gets a bit of roll.

Rick W.

[Willallison]

ASM
You should consider composite flat pack construction. I am confident it could be built within 2000kg using this method using glass composite. I expect prices would be comprabable with marine ply construction maybe even cheaper.


Just a quick note of caution. Depending on thickness, density and skin weight, composite frp/foam or balsa panels are approximately twice the price of marine ply - at least here in Oz. You can usually get them CNC cut for little extra cost though, whereas getting ply cut would be an additional expense. Your weight restrictions may or may not make that extra cost worth bearing. It's also worth considering the additonal skin reinforcement that's required - foam squashes much easier than ply....

[ASM]

HI Willallison

I think the foam core/balsa core is more expensive here too, and as a home builder, much easier to work and get marine plywood. Foam is also a new field, and although one should not be hold back by that, it actually does !

Pericles,

Thanks for the links, especaill the boat builder one is interesting.


I am now in the process of putting all info in 2D CAD, so I can print 1:10 or other scale sections to make a model. Also playing around a lot with the interior, though this should be done in a later stage it is so much fun trying different things out.

[Guest625101138]

.......
I am now in the process of putting all info in 2D CAD, so I can print 1:10 or other scale sections to make a model. Also playing around a lot with the interior, though this should be done in a later stage it is so much fun trying different things out.

Building to 1/10 scale is likely to create difficulty in getting the weight low enough. You have to build the whole boat and fit a drive system with total weight less than 2kg. If you go up to 1/8 scale it will reqire much less effort to get the weight in correct scale.

Rick W.

[ASM]

Rick (and others)

When making the 1/8 scale then, what does that do for the 2.5 t real life compared to ~2 kg for the model ? Is the factor 1250 then (so 10 kg in real life = 8 grams in model ?
This would be interesting to know for simple balance test in bathtub to see how much degree 'hang' one has with a certain weight on the outerside of the model vessel (so people walking on one side of the vessel).. this must show the stability of the low, heavy keel and the possible advantage of the small outriggers.

[Guest625101138]

Mass and volume a cube powers of the dimension. So 1/8th scale results in a factor of 8^3 = 512 for weight. Hence the 2.5 tonne boat equates approximately to a 5kg model. You should be able to build the model within this weight without getting very clever with weight saving, A 75kg person will be equivalent to 150g.

I did stability analysis on the hull and it is very stable if you put batteries in the keel. You could stack a few people on one side without risk of rolling.

Rick

[ASM]

Hey all

Look they have stolen my idea !!!

http://www.dsehybrid.com/DSe_Brochure_WEB_080425.pdf

haha kidding.. but good to see my brainchild was already in some-one elses mind on the other side of the globe and actually build.. proves it is possible !

[ASM]

O, forgot to mention, scrool the PDF till you come to the SPQR page 4, the single hull with amas, and single engine powered....

[ASM]

Rick, and others.

Just found this link, might be slightly off topic , but interesting from hull design and propeller design point of view for solar powered boats.

http://www.deltalloydsolarboat.nl/boot

[Guest625101138]

Found the site hard to understand as it is not a familiar language. Hull is interesting. I do not think it as good as the ASM mono-tri or my variation of it.

The prop is something I am familiar with. This link shows one I designed for a pedal boat:
http://boatdesign.net/forums/attachment.php?attachmentid=20859&d=1209597236

Here is the boat being used for training by my Canadian friend:
http://www.adventuresofgreg.com/HPB/2008_06_29_archive.html

I design for efficient operation. I am continuously rated at 120W and hence have to work hard to get good results.

Rick W.

[ASM]

Sorry for the Dutch language, just the pictures were interesting, the propeller design triggered my thoughts to your design, that's why.

The boat has been build for the solar challenge 2008 here in holland, were one needs big surface for solar panels on a efficient hullform, but also time trials and a minimum of 8 km/hr on average to be prooved before admittance to the race.

[ASM]

Just a quick intermediate update, started sketching the interior and changing the superstructure to a livable area. Have asked quotes to several companies and persons to CNC the frames and hull plating in 4 mm plywood for a 1/8th scale model as suggested by Rick...... will sending more updates when available.

[ASM]

Still working/thinking on the 1/8 scale model. As I will need to cut shapes in the framesections to hold the electrics, shaft and motor, how does this 1/8 scale reflects to the power needed to install ? In other words what kind of electric model boat motor do I need to choose, so I can take the measures for it and pln them in the CNC files ? This planning would be far better then trying to cut out shapes once the bare model hull is finished and I have to put in the engine somewhere..... PLus need to think of stiffening up the frames sections in the keel if I need to 'eat' away too much would to place the electric motor....

BTW I am thinking of using a steerable POD unit as the electric drive, this saves a shaft and its alignment problems, no rudder needed, just a POD (saildrive) in the flat aft section and done ! Or am I too optimistic ?

[Guest625101138]

The 1/8th scale curve is attached. Something like 2.2kts is equivalent to 6kts at full scale. You see this is where the curve kicks up.

The curve makes no allowance for losses. Realistically you could double this power. Still not an issue. You can get motors that put out 50W that weigh a few grams. Powering it will be trivial. I expect you could push it up to 6 knots.

I favour an outboard. It is easy to pull off to work on and can be made to tilt up if it strikes an object. There may be an issue of it coming out of water in heavy weather but I intend to swing a big prop and the motor is speed regulated.

My electric outboard weighs 20kg and will put out 4.5kW continuously on 48V. It is able to do twice that in a burst.

Rick W

[ASM]

Rick

Thanks for the info, so it ooks like I only need ~4 Watt engine to do the scaled 2.2 kts speed...

As for the outboard version, problem overhere is theft of these things, plus something hanging off the back and no clean lines (or one must eat away interior space aft) at the back. On the other hand, nothing to run through the hull construction and it might be an early testversion without going to details and expensive investments when in testphase.