Cruising Cat Width

Discussion in 'Boat Design' started by Inquisitor, Nov 1, 2005.

  1. Inquisitor
    Joined: Nov 2005
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    Location: North Carolina Mountains

    Inquisitor BIG ENGINES: Silos today... Barn Door tomorrow!

    I hate that... can't even go there with a cat.
     
  2. JonathanCole
    Joined: May 2005
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    JonathanCole imagineer

    Hi Stewi,

    Was your boat taken from Berlin to Sete a catamaran? If so, how wide?

    As far as powering a solar catamaran, of course it has substantial battery storage as well as a biodiesel electric generator for backup. Top speed 12 knots cruising speed 5-8 knots. Still 5 knot currents will really suck up the power when going against them. Hopefully these are not stretches of hundreds of kilometers!

    Actually, I am interested in being able to spend the summer in southern Germany, perhaps on the Neckar or a tributary and then head down to the riviera via Rhine/Rhone for the winter. Anybody experience that route? What issues may impact the designed beam of my electric cat? I need as much as possible, since more roof=more power.
     
  3. stewi
    Joined: Sep 2005
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    Location: Atlanta,GA

    stewi Junior Member

    Hi Jonathan,
    Neckar, Heidelberg, good choice.
    No, I didn't have a cat. My boat was 10X3.3X1.5 m.
    I would say up to 4 meter wide, 18 meter long and 1.5 deep is o.k. Otherwise it is just too much stress for a tranquil trip.
    From the Neckar you are doing the Rhine only for a short stretch. In order to get from the Rhine to the Rhone, turn right to the Mosel river. Then you'll be getting to the canal de L'Est and to the Rhone. This was actually the route I took.
    You'll be going upstream on the Rhine and the further South you get, the current increases. Stay close to the river banks. You'll be relief when you get to the Mosel river.
    The locks in the Mosel river have smaller locks for pleasure boats, but not for boats 3 m ++. If you don't want to pay for locking fees, you'll have to wait for a commercial boat to be locked together. Use your radio and contact the lock keeper. By the way, this is as far as you get with English. Once in France, nobody speaks English there. Get the smallest American flag you can find for your flag post.
    The canal is quite narrow and the tree branches from both sides of the river bank meet in the middle. It's plainly beautiful, but no solar energy. I was also going through a narrow tunnel, but I can't remember where that was. It was about 100 meter long. The later the year the leaves may be gone, but than you loose some of the scenery. Fall is nice, the water is covered with leaves.
    Watch the commercial traffic in France on their peniche. They don't make much way and take up the center of the canal. The traffic from metal hulled charter boats can be annoying in some areas. Most of these "skippers" can't get their boats under control. See all the dents in these boats. You'll need good fenders (tires).
    There are always anglers at the river bank. They may not be fast enough to pull in their lines. I had quite a collection of lines and hooks on my prop. I was also lucky, that I tore up a plastic bag and did not foul my prop. There are no dry docks for miles. If you have to dive to clear your prop, you'll have to do it blindly.
    Another thing, when traveling in a small river, the river banks are high and you don't see where you are, unless you followed the mile markers or have GPS. When you get to Arles in France, you'll remember what I wrote. Stop your boat and climb up the river bank. You are in the middle of a larger city. The switch from a tranquil river to car traffic, people and noise is quite weird.
    Stay in Avignon (sur de pond ..) for some time. This is your last chance to enjoy the tranquility before you get to the Riviera.
    We should be moving to another thread for travel tips and destinations. I guess, people with more info may not find your inquiry here.
    Regards,
    Stefan
    P.S.
    With the opening of the iron curtain and the Rhine-Main-Donau canal, I would like to cruise on the Danube (Donau) river to Istanbul. Any infos?
     
  4. Inquisitor
    Joined: Nov 2005
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    Location: North Carolina Mountains

    Inquisitor BIG ENGINES: Silos today... Barn Door tomorrow!

    Electric.

    I’ve been working on a design for a 40’ catamaran. As part of that, I wanted to evaluate using electric instead of diesel engines. My main reasons:

    · I could easily repair the electrical motor (at sea if necessary).
    · I could keep many parts and even entire spare motor for less than 50 lbs.
    · Not having to refuel all the time.

    In my research, I ran across a company…

    http://www.ozecodrive.com/Produkter/Eng/ProdukterEng.html

    … and got an estimate for my projected boat. I also broached the subject of “could enough solar cells be used to power it real time.” Their estimate included two motors and a detected snicker about my solar cell query.

    So, I ran a few numbers…

    For one motor to run at a mere 5 HP, it was requiring 48V at 100 Amps.
    A casual web search gave me a solar panel with: 17.2 V, 2.5 Amps, 4.8 ft^2, 12.8 lbs
    With this, I calculate that I would need 112 of these solar cells. (48*100)/(17.2*2.5) = 112
    That would require 536 ft^2 of deck space and 1430 lbs and $62,000.

    This obviously won’t work at night and it’s for only 5 HP… that might drive my boat at 3 knots.

    Either my math is way screwed up (I’m not an EE) or you have access to far better motors and solar cell than I’ve run across.

    So what boat/system do you have that can cruise at 5-8 knots?
     
  5. stewi
    Joined: Sep 2005
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    stewi Junior Member

    http://web.mit.edu/solar-cars/www/flash/car/the-car.shtml
    If I'm not mistaken it is about 2 $ per Watt and 1/2 m square per 100 Watt and falling.
    Brush-less motors and Li-Ion batteries are likely to make a larger hole in your pockets than the solar panels.
    Locks are closed from 8 p.m. to 8 a.m (and from 12 noon to 1 p.m. Do not disturb a lock keeper at lunch time. Find a sunny spot and re-charge).

    Sails would make good solar panels. But here is another disadvantage of a cat. It is hardly pointing the sails to the sun.
     
  6. JonathanCole
    Joined: May 2005
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    JonathanCole imagineer

    The better solar panels now available put out 12.5 watts per square foot at noon on a sunny day. They cost $4-5 per square foot. They weigh 3-10 pounds per square foot. There are high tech cells that put out twice as much but they are very expensive and don't have the 25 year warranty of the 12.5 watt/sq.ft. ones. So 1000 square feet (50 x 20 ft or 16 x 6 meters) of roof on a solar cat will put out 12.5 Kw/hrs. 1 HP/hr = 746 watt/hr at 100% efficiency. 12,500 watt/hrs=16.75 horsepower hours. But electric motors provide 2-4 times the thrust per horsepower that an internal combustion engine does. So 16.75 HP/hr from an electric motor is equivalent to 33.5 - 67 HP/hr derived from a diesel or gas engine. An aluminum pontoon manufacturer has stated that a conventional 60 HP outboard will drive their 50 x 20 foot houseboat platform at about 8 knots.

    Solar electricity can be stored economically in flooded lead-acid batteries. 3000 watt/hrs of storage in such batteries cost less than $1000, and properly taken care of can last 10-15 years. My boat will carry 20,000 watt/hrs of storage. These batteries can also be charged when at the dock, or in when necessary by an internal combustion engine-generator which can be carried on board. Displacement vessels handle these kinds of weights well.

    Wide beam boats, with large roof and efficient hull designs can be operated with solar energy and can do 50-60 km on a sunny day just using solar power. Its already been done many times. If there isn't enough sun you can wait a few days until your batteries are charged, or you can fire up your biodiesel generator.

    Sails will not make good solar panels because they are largely vertical and you need horizontal surfaces or surfaces with a specific angle to efficiently make electricity from the sun. The best system would track the sun but that is difficult on a boat which is always moving. As a result a flat roof with panels on it will perform somewhat less than peak output, but, practically speaking it is a workable compromise.
     
  7. marshmat
    Joined: Apr 2005
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    marshmat Senior Member

    The setup Jonathan describes above is about what I'd expect to see in a cruising solar catamaran. In solar cars, we have to maximize efficiency at every step of the way- that means 26% cells, Li-ion polymer batteries, and a rather peculiar 5kW brushless motor that is over 95% efficient but costs well over ten grand. A typical solar car array puts out about 120-150 W/m^2 using cells you can buy for your boat; the really competitive cars can get over 200 W/m^2 but that is disgustingly expensive. At a moderate price point and taking the shape of the boat deck into account I would count on 120 W/sq.m in good conditions. Put lead-acid batteries down in the bottom of the bilge (good lithium ones run in the $5,000/kWh range, not worth it on a boat).

    So all in all: Solar cells in the 120 W/m^2 range, lead acid batteries, a good marine electric motor on each propshaft (properly sized for the boat weight of course).
     
  8. JonathanCole
    Joined: May 2005
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    JonathanCole imagineer

    That is the other important issue for a solar catamaran - weight. You know you have these heavy batteries, solar panels and lots of wire and electronic equipment, so you don't really want a ferro cement hull to add to the load. Light weight and strong is the key to a successful electric catamaran. The less weight there is per unit hull volume, the less draft and thus the less wetted area and resistance you have. Sounds like aluminum (although I have not given up on rotomolded HDPE) cat hulls with 16:1 + L/B ratio, super fine entry, and probably an identical stern with the widest section 2/3 of the way aft. Since you need efficiency, that suggests a rounded bilge. Although at less than 12 knots I am not sure how important the rounded bilge is. Since a rounded bilge actually has less volume than a squared bottom of the same hull width, the hull volume with a rounded bilge will sit deeper in the water and some of the advantage of roundness will be lost. Anybody ever done any calculations on the speed crossover point where a rounded bottom actually is superior?
     
  9. stewi
    Joined: Sep 2005
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    Location: Atlanta,GA

    stewi Junior Member

    Hi Jonathan,
    since your hull is not planning but only displacing, the hull length, surface smoothness and area should be the only factor impacting the speed. In this case a cat is not ideal.
    I remember, some time ago, somebody did an around the world navigation with a single engine Volvo in a trimaran. The main hull was very narrow and the amas only to balance the boat. I found it: http://www.popularmechanics.com/outdoors/boating/1276951.html
    If your main hull is about 15 m long and the boat with amas 4 m wide you can still navigate the canals in France, but I believe with a more effective hull shape.
    I drew up a hull 600" long (581" in the waterline) beam in the waterline is 36". Estimated displacement 8000 pound:

    P.S. of course I was just kidding with the sails for solar panels. I got into a discussion with Inquisitor on mono's and cat's and I was trying to score another point.
    Cold moulded plywood also come to my mind for a light hull and it may be a better choice for home built.
    If you need some more travel info off the forum stefan@wittemail.com
     

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  10. yipster
    Joined: Oct 2002
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    yipster designer

    jonathan,
    all very interesting but i dont think weight is that important for your cat.
    why not consider steel wood or polyester?
     
  11. Robjl
    Joined: Nov 2005
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    Robjl Senior Member

    Inquisitor,
    I have some experience here with high efficiency brushless DC motors. I have made, yes hand made several but only up to about 800 watts output (not the electronics though). We tested these with a simple pulley friction system to calculate efficiency. Our best including the electronics to drive it was 85%. When I hear about 93% efficiency plus I think of how they remove the seals from the bearings, wash out the grease and add a few drops of light oil, these claimants often don't even include energy losses in the electronics, If you have a look at PCBs you'll notice the big heat sinks, I guess they just keep the moisture out! The efficiency will also not be constant over the rev range and power output. Work on no more than 50% efficiency no matter what they say. Then the batteries that last 10-15 years... get that in writing too. And the solar panels that put out say 80 watts, that's for maybe 3hs per day in very good light, clouds will knock it back... for the other 3-5 hours/day the output will be reduced... oh! and the performance of the panels will drop off as the years pass.
    The best set up that I have seen " achieved", not in something like the $10,000,000.00 Honda solar race car, but in a useable boat is written up in the "Aust Amateur Boatbuilder" #49 March 2005. The article was reprinted in a US magazine recently, you may be able to find it. The boat was called Nomad III.
    Imagineer says "But electric motors provide 2-4 times the thrust per horsepower that an internal combustion engine does."
    If he can get 2-4 times more thrust(energy) out of an electric motor compared to a internal combustion engine per horsepower a lot of people will be real keen to patent it, mabe I missed something.
    I think there is nothing wrong with your assesment of the electric alternative, there is no easy alternative power system, maybe one day our kids will be emptying the food scraps into the back of the Delorean, but right now the electric system won't perform like the tank of diesel it replaces, it definately has it's uses and a future but at a big current and ongoing price. I don't know if any-one has replaced the batteries in their Prius yet and then worked out what they have actually saved. Yes, OK, I can hear you, what about all the pollution saved from the vehicle... you mean the pollution that was transferred to a remote power station.
    My advice.. a nice quiet, efficient, low emisions industrial diesel, as an auxiliary to your sails.
    Regards all, I'm ready for the flak.
     
  12. stewi
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    stewi Junior Member

    I’ve seen that efficiency thing before and as an EE caught of course also my attention.
    However, here is some other math. Lets say the panel puts out 100 Watt at 50 % efficiency and I paid $ 200 for that panel. After 10 years, I put the panel in the trash.
    In 100 days a year and 10 hours a day it produced in 10 years 500000 Watt, which is 40 cents per kilo Watt.
    Oil producing countries investing their $$$ in alternative energies and solar cells are the number 1. Prices for solar cells as well as efficiency per square foot change by the month, almost as fast as the computer clock speed changed years ago.
    I think, I’ll live long enough to drive a solar car.
    I found the link to Nomad III http://64.233.187.104/search?q=cach...nomad III solar energy&hl=en&client=firefox-a
     
  13. JonathanCole
    Joined: May 2005
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    JonathanCole imagineer

    No flak here. Most people are more comfortable with the familiar. But some like myself, are early adopters of new technology. I am also a mechanic, an electrician, a carpenter, an engineer, an entrepreneur, and a specialist in solar electric technology since 1983, so I actually build things from scratch if I can't buy them economically on the open market. Works for me. Nothing against sailboats - have spent many happy hours cruising the Carribbean in monos, cats and tris, but I hate the smell of diesel fuel.


     

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  14. stewi
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    stewi Junior Member

    Let me try to draw a larger picture.
    Between 1999 and 2005 ~ 400,000 jobs in US were lost due to job transfer to China. Most of these jobs came out of electronic device manufacturing. In the beginning the quality was lousy, but it is catching up. Another small hurdle was the technology transfer as well as clean room environment required for the silicon wafer manufacturing.
    Another boost came from lead free requirements originated in Europe and surprisingly adapted in US. However, China never signed any copyright issues nor do they follow lead free restrictions on the solder joints. Silver instead is too expensive. Not to mention how to dispose other hazardous materials like arsenic or replacement chemicals, required for doping the silicon and make it semi-conductive.
    China has a lot of cheap labor, but zero oil to produce energy to produce silicon and make solar cells. It also requires much more oil to switch from a bike to a SUV.
    Well, the oil comes from Iraq, the US happen to make war with, with the money from China.
    In the meantime the oil producing countries realize, that the oil income may not last forever. So they invest in alternative energy. There are multi-million dollar projects in Saudi Arabia and other oil producing countries in solar energy and energy saving projects. These projects are not paid in dollar, but through a consortium in oil.
    Now we can close our eyes again. This is all not happening. Solar cells, what a nonsense.
    Keep on going, Jonathan. You are way ahead of us. ..and you were already since 1983. I don’t like the smell of oil and diesel either.
     

  15. marshmat
    Joined: Apr 2005
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    marshmat Senior Member

    Jonathan, Robjil:
    I guess it might be unfair to talk in terms of absolute efficiencies here. Yes, the motor-controller combo in a modern solar car runs over 95%. It also can run over $2000 per peak horsepower to buy. Taking a slight hit in efficiency gives you a much lower purchase price, a big factor in a boat. Paying 10x as much for a 95% motor versus an 85% unit is a difference you will never recover, especially in a boat where weight's not critical and you can already tweak propellers, controllers, etc. to suit the application.

    I wouldn't be quite so hard on gas/diesel engines either. From fuel to road, a typical modern car engine is 24-26% efficient; some, like the Volks TDI and the gas side of the Toyota hybrid, are about 30%. (Compared to the 10-20% range of '70s car engines.) Your typical good boat diesel might be anywhere from 20-30% from fuel to propwash; big container ships get up to 50%. Modern diesel technology is getting quite good on efficiency, especially with plant-derived (as opposed to refined oil) fuels.

    As for the Prius batteries... well, my uncle just bought a Prius, and my parents just got a Jetta TDI. I'll get back to you in 10 years with the verdict. (And no, the pollution is not transferred to some other station; over the manufacture and total life of the Prius, total emissions of CO2 and most pollutants are on the order of 1/2 to 3/4 of those for the Matrix, its closest non-hybrid sibling.)

    I'll stick with the solar car.
     
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