Cheap to run, cheap to build electro plywood cruiser ?

[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]

Originally Posted by 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

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]

Originally Posted by FAST FRED

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]

Originally Posted by 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

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...-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/...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 !