Choice of electric motors as inboards for a catamaran

Discussion in 'Electric Propulsion' started by xellz, Jul 16, 2017.

  1. Mickdh550
    Joined: May 2018
    Posts: 7
    Likes: 4, Points: 3
    Location: Melbourne

    Mickdh550 Junior Member

    I’m not sure it’s been discussed here but AC motors with frequency variable controllers are really a great option. There are lots of people who have done research on this and it’s theceay I would like to go.
  2. pacific green
    Joined: Oct 2017
    Posts: 10
    Likes: 1, Points: 3
    Location: earth

    pacific green Junior Member

    Solar Catamaran I really think the OP is going in the right direction electrically. His choice for the Skoota class would be mine as well if I could find a used one that I did not have to build. Otherwise finding a Catalac catamaran would be a good start and they can be had for reasonably cheap in comparison to home building your own Skoota 28 or 30 foot.

    Stay away from parallel connections in batteries on a boat and don't get too hung up on energy density of batteries versus weight. For simplicity go with 16 cells in series at the largest amp hour capacity you can afford. Just search for 400 amp hour winston cells and your on the right track. Forget the diesel generator your banging your head against the wall on that one. A simple Honda 2000 will provide all the power you will need for very little weight or fuel cost and is also easily replaced and fixed.

    Consider a Rayeo 48v electric outboard or two. Mort Ray had electric outboards figured out 50 years ago and all the outboards he ever produced are still in use today. Then again I certainly am biased towards the 48v outboards from Rayeo as I run dual outboards centrifugally placed.

    I dream of electrifying a Skoota 30 every day. Or at least a catamaran hull designed more for speed. With 3 seasons now on my solar electric catamaran I couldn't be happier. Then again you would actually have to experience living aboard for a couple of weeks to believe it. I'm working on uploading the bulk of this years 165 cruising videos where we ran a dual Honda 2000 configuration each powering an old lestronic charger for 20 amps plus the sun to recharge at close to 50 amps for most of the day.

    The dual Honda generators this year were amazing. Sure we burned more gasoline but it was more controlled. If we didn't have to move and the sun was charging us up we wouldn't have to start the generator for three or four days. If we had to run generators underway it allowed 20 amps to each prop with whatever solar we could muster. That was at time augmented by the reserve in our massive 20 Kwh battery bank. Honestly you don't need much more battery capacity than that.

  3. xellz
    Joined: Jul 2017
    Posts: 124
    Likes: 6, Points: 18
    Location: Japan

    xellz Senior Member

    I'm quite stressed recently, so little bit steam out here:
    Thus far my experience with this idea was quite frustrating, anything that could go wrong, went wrong. Initially planned with partial financing from village for people who will do commercial fishing or create work place on the island, public workers didn't read well requirements and they found out some problem with me receiving it, but a lot latter. Okay, i still thought i can do it on my own. I bought plans for Jazz 30 last year in november and of course luck was again't me again, the data was lost and there was no backup, i.e. plans had to be re-drawn from scratch. So only recently i could more or less clarify if i can get all permits i need, of course it also depends if finished boat is build to plans without mistakes. Plans aren't fully complete yet, but the end is near at least. Since plans and permits were taking so long, i decided to buy used mono and use it for few years until i can switch to catamaran. I found old 28ft fishing mono with inboard diesel in decent condition and started the process of buying in april, maintenance and repairs supposed to be done by beginning of june and guess what happened? Boat still is not with me, 1-2 weeks left until i can finally bring it to the island.

    In Japan for me it makes more sense to build boat, rather than searching used cat. Choice is really small for cats, they are expensive even if quite old. I'm not planning on live aboard, i.e. basic equipment is really minimal, in fact i can start with just fish-finder and legally required equipment, like lights, safety gear etc. Cost of materials with import expenses to Japan should be somewhere in 15.000$ range, at this point i have only rough estimation. In worst case go with ICE outboards, 20-30hp outboards aren't that expensive even brand new. For this price i can only get rotting cat with lots of gear and tools that are completely useless to me and can't be sold for any profit, in addition hull shape is less than ideal for my needs. Old mono hulls can be found for free, with engines beyond repair or in really bad shape. But they are really heavy and meant to be used with big inboard diesels and lots of hp to waste. There was one boat available on island where i live for free, engine requires overhaul and seems almost no spare parts are sold anymore, no fish-finder or gps either. Hull requires some repairs too. So overall expenses were higher than buying a boat in working condition. With options i have available, building myself seems the best way.

    If i go electric, i definitely want inboard solution. Better protection from harsh environment (in addition to salt, volcanic gases and acid rains), outboards are in the way, they take quite useful space, with inboards can eliminate the noise completely. Aesthetics also important, i'm trying to make work place i truly enjoy. I won't be designing electric propulsion myself, not only it has to be safe, but also pass various inspections and for commercial use, those inspections are a lot more strict. For personal use it might be not necessary, but i don't see Honda 2000 and similar gensets being certified to use in marine environment and this can be an issue. So question of additional source of power is still open.

    Despite all setbacks i'm still moving forward and not abandoning my dream. I hope no major problems will appear anymore, so i can at least order materials this year.
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