fishing trawler to pleasure conversion

Discussion in 'Boat Design' started by James Wellington, Dec 27, 2022.

  1. James Wellington
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    James Wellington Senior Member

    Yes, and look up aerogel insulation......formerly only used in space stations, etc...now appearing all over.
     
  2. Rumars
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    Rumars Senior Member

    Please don't take me wrong, but you need to get your head out of the "better material" trap.

    Aerogel is the perfect example of you beeing blended. Yes it insulates better then everything else except vacuum panels and doesn't burn. At the same time it's an open cell material that is highly permeable to water vapor. This means you need to apply the same precautions as with rockwool, namely a gap against the hull for condensate to flow to the bilge. Given that you also have to insulate the framing and install a ceiling, there is no advantage to using a thinner insulating layer. There is a reason aerogel isn't widely used, and it's not price, rubber foam also gives you sticker shock.

    Another example is you insisting that hybrid drives are more economical without understanding the operating conditions under wich this is true, namely frequent stop and go. Solar simply can't supply enough power unless the hull is highly specialized for low power drives.
     
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  3. comfisherman
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    comfisherman Senior Member

    Rumars, thanks for a longer response. It's probably more useful than my tongue in cheek "maybe they have new aluminum".

    I'd typed out a long response describing the reason hybrid works better on a long line boat, as well as ways we've mitigated cold on boats with aluminum superstructure.... then I realized I was on the internet typing on a forum that has almost no bearing in industry or current manufacturing reality and deleted it.

    Onward and upward, just think of the movie theater and cozy den you could make with the fish hold on those puppies...
     
  4. James Wellington
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    James Wellington Senior Member

    Aerogel was a suggestion as per the real old alu boats he used to be on. Im notcsure what all the brand new alubboats use mostly. But I have read that its,showing up in some boat applications too.

    Re hybrid boats, I never said solar can supply all motive power, but have frequently disgussed gensets. Seems you missed most of my messages.
     
  5. gonzo
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    gonzo Senior Member

    I worked on an ocean tug with diesel/electric drives. We had 8 generators that turned on according to the load on the motors. Also, because we did geological surveys, speed control was crucial. I supposed there may be an application where a hybrid is more economic than a diesel. However, unless I see a proper cost analysis, I think it is wishful thinking and following a fashion trend.
     
  6. comfisherman
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    comfisherman Senior Member

    For the long liner it makes a lot of sense. We spend 12 to 15 hours a day sitting on the line, usually set to go with wind or tide. Traditionally slipping with a trolling valve of some kind to creep down the set. I remember a lot of days sitting atop the controls of a 6170 lugger with the gear at max slip and still having to pulse in and out of gear to not overshoot or strain the line.

    Usually we always had a big generator running with the small hydraulic pump going. We ran 8 kw of sodium all year long to add some load to the generator.

    Probably 12 or 13 someone made a more robust version of a get home drive and installed it on a long liner I'm familiar with, similar class to the one in the op. It allowed the main to shut down and the electric motor connected in where a gear based pto would go. I think it was limited to very slow rpm and about 80 hp max. They ran a pretty good battery bank and the always present generator had some kind of charger to fill capacity as needed. Allowed the 19 liter main to shut down and the excess load from the generator to be put to propulsion and not waste. I know the summer time captain of the boat loved it, winter captain was not as impressed. Keep in mind these are operational speeds of 0 to probably just shy of 2 knots.

    To my knowledge the chargers had considerable trouble, and around year 3 some kind of linkage between the gear and the DC motor broke down. Few months later a battery fault caused a fire and they pulled the batteries. I was fishing on a boat at the time with a massive crane with an abnormally wide swing over the side, and they had us pull the batteries as theirs was out of commission from the fire below it. Takeaway at the time was it was cool, but not yet ready for prime time. The cost was also stunning and when the sea grant ran out so did the desire to keep it going.

    Now it runs a small hydraulic pump with a pass through overhang load adapter rolling a big alternator. Instead of running it off the generator, now everything is run of the big main. In a way it helped nudge towards more efficiency, not 25-40% but something.

    Keep in mind this system would never get you to 5 knots, and added the cost of the average American house to the build price. Mainstreamed and better engineered, it could be the future. But fisherman have way different power consumption needs.

    On the aluminum side. My last alloy project needing any real volume of plate was 21. We blasted the inside and used the latest and greatest closed cell foam we could get. It was a dollar a pound over standard and shot at specific Temps to get densities just right. The big one was isolation, usually alloy angle or t bar are in place to hold machine screws to hold paneling. Having seen the alloy stand off pieces conduct heat we faced each one in an air cure cerakote and then synthetic 1.5x1.5 boards. It definitely was better, but we use a similar method on glass, but glass isn't tons of heat sink. The project turned out nice and the boat is used may to Sept in a state where summer Temps break 75f but not every year.
     
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  7. Rumars
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    Rumars Senior Member

    Comfisherman, thanks for taking the time to detail a use case where hybrid makes sense, I appreciate it. BTW if your friends want to try again, the place to look for components is light urban traction (tram, buses). You can also get dual input gearboxes on special order.

    Outside the US spray foam is not very popular, rockwool and armaflex are used.

    Mr. Wellington, I asked you to detail your use case. All I have read to date doesn't support the case of either diesel-electric or hybrid drive. If I missed anything please go ahead and explain.
     
  8. gonzo
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    gonzo Senior Member

    Diesel/electric is amazing for fine speed control. However, we were billing $48,000/day in 1982. That is $152,000/day in today's dollar value.
     
  9. comfisherman
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    comfisherman Senior Member

    I think I want to be really specific and clarify that the use case scenario highlighted showed a proposition where it "could" work. Not necessarily one that "did" work. Considering some of the competing boats are rocking drivetrains that have multiple top end rebuilds and are coming up on old enough to retire in linear age, 3 years partial use isn't an unmitigated success.

    With that said I think electronic fuel injection for the last 15 or so years helped bridge the gap most fishing boats have to cross. Namely the disparity in power need, between light looking and heavy loaded travel. Putting along as slow as possible watching the shelf on sonar, or running long line is way different than a full stack with a full tank towing a bag in wind and tide. The idea of hybrid certainly begins to look more appealing. Although my personal preference would be a reincarnation of a y drive. Although I've not seen any mainstream product, and they would have to come up to speed to beat out a twins disc 5170 in reliability.

    For straight line running, as is the case in cruiser operations I'd take straight shaft diesel drive every time.

    My big hang up is the utilization of any of these fishing boat designs completely pleasure operations. Boats built for either the North Sea or the North Pacific in the last 30 to 40 years are all some form of rule beater. Meaning their design parameters are meant to get more capacity shoved into a shorter water line length. Usually they have a perishable product aboard that requires returning to port and fairly frequent intervals. As such some of the design parameters don't lend themselves to long distances or efficiency.

    The upside is they are cavernous. But even commercial fishing boats designed to run longer distance like high seas tuna boats opt for much more streamlined hull forms. Don't get me wrong, I love fat, tough, grossly overpowerd fishing boats. It's been and will be much of my life on and around them, but for straight lines there are probably better mouse traps. That's why the suggestions of a hull form of the traditional delta. It was designed in the time of oil embargoes when we made a boat for the sake of it being a boat. Hull forms like that would be where I put my time and effort.
     
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  10. James Wellington
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    James Wellington Senior Member

    Mr. Wellington, I asked you to detail your use case. All I have read to date doesn't support the case of either diesel-electric or hybrid drive. If I missed anything please go ahead and explain.[/QUOTE]

    OK, all the evidence in favor of hybrid could be wrong, and ALL those big famous well respected builders could be selling ALL those hybrid boats to people who havnt checked them out. Of course its also possible, you just dont know about them.
     
  11. James Wellington
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    James Wellington Senior Member

    With 8 generators it must have been some huge ship, not the small ones like we're talking about, 50-80 feet snd such..
     
  12. Rumars
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    Rumars Senior Member

    Care to share that evidence? I am really curios to see how they did it.

    Physics tells me that every conversion step consumes energy. A straight diesel driveline has two steps, diesel to mechanical work via the engine, and mechanical work to mechanical work via transmission. A diesel-electric has four steps, engine, generator, VFD or chopper, motor. A hybrid adds two more, converting electricity to chemical energy (battery) then back to electricity.
    The engine efficiency between passagemaking at constant rpm and generator duty is not very different, so the comparison is between losses in the mechanical or hydraulic transmission and all the electrical conversion steps.
     
  13. fallguy
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    fallguy Senior Member

    All your excellent points aside, it might be helpful to explain then why anyone would desire all this conversion....
     
  14. comfisherman
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    comfisherman Senior Member

    For the same reason the boat I talk about did it, gubmint money....

    It works in a lot of other areas where there is lots of excess energy or other linked inverse loads.

    Big band design outfit designed one about a decade ago maybe smidgen more. The power generation was managed by generators larger than the propulsion required. It's sister ship operated with two smaller cats with two larger cats for power one for Maine and one for backup. An attempt to balance the load better put five cats in series. The idea that the processing was most energy intensive when propulsion was least, reciprocal being also true. Turns out it didn't take long for the wind to blow in peak fishing, requiring all power all the time making for the illustrious more fuel green plan. In optimum conditions, it appeared to work OK as it does very successfully in the cruise industry. The design Co was smart enough to have it pre-designed for ice engines and rather quickly it was converted to good old fashioned diesel.


    In the 50 to 60 foot range the boats that successfully do hybrid for more than just driving around the harbor, look like racing catamarans. Weights, windward areas and latitude ranges are all very carefully considered. The other group sells hybrid more as a lifestyle accessory. One I read recently advertised silent dinner cruises around the harbor as a selling point. Fine print mentions the pesky range reality.

    Big old slab sided hogs were talking about.... not so much.
     

  15. Rumars
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    Rumars Senior Member

    The case for DE transmission is pretty clear after 120 years since it's first use (Vandal 1903), low speed high thrust, azipods, hotel or processing loads exceeding propulsion needs, flexibility in machinery positioning, redundancy, highly variable load needs. Typical applications are tugs, cruise ships, icebreakers, offshore processing, patrol boats and recently some types of fishing boats.

    Hybrid propulsion with batteries (you can also have hybrid combining DE and straight diesel, Sarmat 1904) is a different animal and has to be carefully considered. Fuel savings depend on applications with a significant amount of time on very low power and frequent recharging opportunities. The economics are difficult because fuel is cheap and batteries expensive, you need a lifetime analysis. Sometimes there are also other considerations for hybrid, like for example in Venice, where one public transport boat, on the Canal Grande it's battery electric respecting the 5/7kmh speed limit, while out in the lagoon it goes DE, doing 30km/h and recharging the batteries at the same time.

    Off the rack solutions exist for low and high power applications. For example Siemens has the EcoProp in two versions, up to 200kW, and up to 600kW (single generator, there can be more generators and one generator can power several motors). The low power version is a marinized version of their bus tech, ELFA.
     
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