CNC Plans not Included

Discussion in 'Multihulls' started by jorgepease, Sep 19, 2016.

  1. jorgepease
    Joined: Feb 2012
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    jorgepease Senior Member

    Yeah, I hate always being wrong!!

    2 small 20 hp outboards say 8K including controls only weigh in at about 100kg. I would go with 2 of the batteries at that price and a ton of flex lightweight solar panels on my huge Bimini and no generator. Maybe a couple of fuel cells for backup when wind and sun are nowhere to be found.

    These boats are going to be awful light, I think they may end up being faster than the SIG!
     
  2. groper
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    groper Senior Member

    Be careful with those flexible solar panels...

    The boat which you may know of built by another aussie called "roam" - a spirited 480- you know of it? Well he installed 10 of them and in 1 year, 7 of them have failed.

    They may not all be unreliable, but there has to be a problem with heat. The cells don't have cooling without the air gap under them. This not only reduces their output then we they get hot, but probably shortens their life aswell...
     
  3. jorgepease
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    jorgepease Senior Member

    I have been keeping an eye on them, they get better every year, more efficient and durable and I would only buy from the top major mfg's that are going to be around to honor the warranty in 10 years.

    The standard household panel is more efficient but adds about 3 + lbs per sq ft. If I used 6 - 17sq ft panels on each side of the roof I would be adding at least 800 lbs of weight up there.

    The thin film version which you can walk on would probably only add 100 lbs. That and the electronics will be the last items I purchase so hopefully more innovations.

    On the electronics, I am really digging how everything is going wifi and being integrated into one or more displays. This is going to cut down on rigging that stuff dramatically and save precious space.
     
  4. groper
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    groper Senior Member

    Must be some error in your weight Calc.

    If you looking at solar - my recommendation would be 4x sunpower e20 327w. Total weight is 164lbs for 1.3kw max solar input.

    This is plenty of power for most cruising boats. Especially if you augment it with 1 wind turbine, I doubt you'll ever have to think about power. You could probably even run a small inveter air conditioner provided there's plenty of sunshine and you have 14kwh in the power wall 2 system- with non electric propulsion that is...
     
  5. DennisRB
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    DennisRB Senior Member

    I'm not against electric ideas at all, as it may seem. I like them when it makes sense. What I don't like is the total BS drivel that come out from the sellers in regards to performance and comparisons.

    Good to see you have made a rational decision based on evidence rather than sales pitches. The OBs suits your SOR much better.

    If you use the regular rigid glass cells you may be able to design them into a hard bimini somehow, saving material from the areas of a hardtop and also increasing the efficiency due to cooling airflow from the bottom. You may fit more than the 1300w odd Groper suggests. By the time you need to buy them those similar may be 1500w anyway.

    Cooking and filling dive tanks etc may then be a real possibility with a very large array and supplementation of a very light and cheap portable petrol genset as a backup. Your cat, your genset, your cooking and your real planing tender will all run off the same fuel, further reducing weight and hassle and tankage.

    Simple is the best AND cheapest :)

    Tesla has good exposure, but look into BMW lithium batteries. The specs are better, cheaper and more compact. But this is pointless. I would think of brands at the very end of the build as this emerging industry is changing so rapidly.
     
  6. groper
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    groper Senior Member

    Well said...

    I've seen rigid solar panels being used as the Bimini itself as you suggested. It was on a house boat over the top deck. I think it was 10 panels mounted to a stainless or alum tubular frame. The panels and their glass tops effectively became the roof and it was all working quite well for a number of years when I saw it.

    I only have 600w of solar on my roof and I have plenty of power to run 240v fridge and freezer and watermaker electric hot water etc. 1.3kw should easily do me if I had a washing machine and air conditioning aswell. I don't even carry a portable generator.

    Anymore than 1.3kw of solar, with a wind turbine and 14kwh house bank, is getting way over the top for a performance cruiser. I can't imagine the need for 12 panels (3-5kw) it's just ridiculous, unessesary weight and $$$.... 6 panels maybe if I had the real estate (2kw) is heaps...


    One thing about the power wall 2 is its probably setup as a 48 volt battery and inverter. Not going to work with all the 12v gear unless you run a DC converter with it...
     
  7. jorgepease
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    jorgepease Senior Member

    I like the idea of using cells to also act as the roof.

    If using the flex panels they could sit on a tennis racket like rack open to the bottom. I like the idea of loading up panels because I read an article that suggests you will likely only get 6.5 hours of full production and possibly less depending on conditions, shade etc... per day. The same article suggest connecting each panel to it's own controller and they showed various installs where the panels could be removed or moved.

    According to residential home installs - the lightest panels, including rack added 3 lbs per sq foot of weight. 100lbs is only 33 sq foot. That sounds more like 2 panels?

    I don't know about the battery voltage but since I will be building to CE everything is going to have to be pre engineered to the T like the Torqeedo system.

    Been thinking about drives again. Since the whole idea is to sail, not motor around, I would rarely use them. I don't know much about sailing but I have had so many outboards and they like to be run ... and gas likes to be fresh so it's not a cut and dry decision in my eyes.

    I think I will try with electric outboards first. I really don't want fuel aboard, freedom from fuel is high on my list but if I find I'm constantly wanting to motor around or motor at higher speeds then I can easily switch to traditional outboards.
     
  8. jorgepease
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    jorgepease Senior Member

  9. DennisRB
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    DennisRB Senior Member

    But you have been given advice from experienced cruisers like myself and Groper.

    Its a romantic notion that gets in the way of reality that you wont want to motor for long distances at times to pick up friends, meet deadlines, power against prevailing tradewinds during periodic days of calm, to beat weather systems and to be mobile in the even of rig failure. Want to sail from Tonga to NZ? Well better motor flat out for a few days on the back of a low so you get there before the next potentially deadly one builds to full strength. Sure you don't HAVE to do that, but its a lot safer.

    I know people that never motor. Of course you can do it. Its just that you cant do the important things above that most people would want to be able to do.
     
  10. Timothy
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    Timothy Senior Member

    Torqeedo now has a 10 kw outboard. My experience is the same as Groper's. 600 watts solar is plenty for house loads. I have the flexible type, 100 watts and 4 lbs each, which after four years are still fine. The ones not directly mounted on the deck are supported by frames and lightweight grids.I am not sure if there is much difference in performance. You can count on about five hours a day full power depending on your latitude and time of year. Use separate controllers for panel groups fore and aft and port and starboard as panel groups in even partial shade will loose up to 90% capacity. I figure you would need at least a 6 kw array with two Tesla power walls or the equivalent to motor all night at less than half throttle, depending on the displacement and length to beam ratio of the hulls. There is now a company that makes sails partially from solar cloth.
     
  11. jorgepease
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    jorgepease Senior Member

    https://www.emarineinc.com/Gioco-170W-Flexible-Monocrystalline-Solar-Panel-GSC-170

    Flex Panels have improved … Take these Monocrystalline 170 W panels for example - They weigh less than 6 pounds and are roughly 60 inches by 27” by 1.5 mm thin.

    The roof has more than enough area to install 30 of them for roughly 25KW over 5 hours. I guess if you wanted to power around during the day (one motor at slow speed) you could without barely touching the batteries.

    At this point we are talking no generator, no fuel, what the heck, might as well add 2 more batteries to keep the boat from being blown away and I will still be as light or lighter than the SIG 45 which I have seen reach 27 knots in San Fran Bay on youtube.

    That is a boat that can sail in 5 knots of wind so while I don’t discount good advice, I also have to consider that this is not the type of boat you are used to sailing
     
  12. DennisRB
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    DennisRB Senior Member

    Those panels cost about 8 times what regular ones cost.

    I have never sailed a Sig 45. I'm sure its pretty fast. It would smoke my last boat in all conditions. But I have not exactly come from a charter cat either. You do have to consider you are not really used to sailing just about any type of boat going from your previous comments :p Does the following look slow in light air to you? Thats a 19m rig on a 13m PVC and kevlar cruiser racer with 140m2 of sail. So sure, Bedar can sail in 5k too. Below we are doing windspeed in 8K and we motored a LOT. It is my real life experience on a fairly high performance and excellent light wind performing cat, that I will never give up long motoring range of decent speed say 7k. These experiences come from living aboard and cruising rather than a preconceived notion of what it might be like to do so.

    That said, with a decent genset the requirements might be met. What is the expected continuous speed available from the system you might be considering?
     

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  13. redreuben
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    redreuben redreuben

  14. DennisRB
    Joined: Sep 2004
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    DennisRB Senior Member

    New, as in 1985! :p I hope it takes off for them finally on a commercial level. The idea seems good.
     

  15. jorgepease
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    jorgepease Senior Member

    Nice picture :) looks like good times ... Do you mean motoring? Probably around 4 knots if that but I am not expecting to motor. I actually don't like the noise from motoring so it would be only when I really need to. I have no pressing schedules, I've had that all my life, I'm done with being in a hurry. The speed aspect of this boat is not so I can get there fast, it's so I can have fun at times and sail in light winds.

    Yes, they are pricey but I hope prices keep coming down

    Yes, Tesla is not the only kid on the block - https://cleantechnica.com/2016/11/23/introducing-cleantechnicas-new-home-battery-overview-page/
     
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