Electric Leisure Boat Design II

Discussion in 'Boat Design' started by slboatdesing, Aug 9, 2022.

  1. mitchgrunes
    Joined: Jul 2020
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    Location: Maryland

    mitchgrunes Senior Member

    I can't comment on the Jet Lark, though it is stated to need work. But can your vehicle tow a trailer?

    If all you want for now is to be on the water, you could buy something cheap but light enough to car top, that doesn't need fixing or converting, like an old kayak or canoe, along with safety gear (e.g., life jacket, water bottles & food, normal and spare paddles, etc.) take a lesson or two, and go, preferably in a group with other people who know what they are doing. But perhaps you are more interested in the build than enjoying the water. Some canoes are shaped to allow attaching a small motor should you want that later.
     
  2. slboatdesing
    Joined: Aug 2022
    Posts: 116
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    Location: Maldives

    slboatdesing Senior Member

    Relevant Experience

    A one-day trip to a nearby island resort provided some invaluable boating experiences for me, and very much in line with this thread. A more full description would take many hours but here is the summary:

    Speedboat ride

    My first time in a speedboat of this type, with its 2 x 75 hp or more outboards, measuring 96 dB with wind noise and other noise running in the background. Boarding was complicated by the intense rocking motions due to waves from passing boats. Once under way, we quickly accelerated to 30 knots plus, the fastest I have been in a boat, however there was very little rolling motion, maybe 3 degrees maximum as measured on mu clinometer app.

    The ride was relatively smooth, with some waves causing momentary pitching and splashing, but they sure designed this hull right. No motion sickness was felt by myself or any of the passengers, family included, which is saying a lot.

    An unexpected feature of the sea was the presence of large 'hills' of water, huge, undulating masses that looked like hilly meadows only this was the sea, and although it caused no resistance to our passage, it was unexpected to be 'downhill' of a wave, and see the mass of water approach the horizon.

    As we swooped in to the resort with the boat tilted at what seemed like 30 degrees, I was disappointed it was over.

    30 knots is too too fast for me. We could have done 20 and saved a ton of fuel I am sure. The boat I was on for dolphin watching was better, about 7 knots as I remember.

    Pictures and files will be attached:
     

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  3. slboatdesing
    Joined: Aug 2022
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    Location: Maldives

    slboatdesing Senior Member

    Thanks for the advice Mitch.

    You will all be glad to know I am really liking my time in water, it is fascinating. Moving using the wind on the catamaran, my first time ever on the sailboat, was magical. So in the past 2 days I have been on a speedboat, a dhoni (large traditional vessel with a diesel engine going at about 7 knots - dolphin watching) - and a catamaran.

    I thought of building because it seems cheaper, and incremental, not to mention rewarding.

    The recent boat rides described above helped, including the weird and interesting catamaran excursion.

    How about a sailing Kayak? I swear the kayak I rented had a hole in the middle for a sail mast.

    So to summarize:

    I want to move on water - electric motor, sail, pedal boat, solar powered or even powered by compressed air?
    I do not want to paddle (maybe rowing)
    I do not want to swim
    I do not want to capsize

    That sums it up.
     
    Flotation likes this.
  4. slboatdesing
    Joined: Aug 2022
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    Location: Maldives

    slboatdesing Senior Member

    Catamaran

    A few metres from shore, we are moving. How, why? It is all very mysterious, there is hardly a breath of wind, and those tall sails must be making something happen. My first time ever on a sailing vessel of any sort, and the silence and magic of the moment will never escape me, I am sure.

    Further out to sea, out of the harbor, and we are moving, rudders partly down, and some pulling of the ropes on the sails, and we are really moving, is this about 7 knots I ask, this is about 5 or 6 knots I am told.

    There is nowhere to sit. I find a place on the trampoline, it is just me and the captain, and watch the waves hit the front of the twin hulls, cutting through. There was not much rolling, however, the entire vessel seemed to be leaned over off-kilter, which was mildly unsettling. I had to move to one side or the other depending on the sail settings, but managed to hang on, reclining, resting, sorely missing a seat of some sort. The waves splashed through the trampoline wetting my shorts and the waves over the bow splashed the rest.

    Out to sea we skimmed over coral reefs, light blue water, rocks, all with the rudders half way up. We skimmed, we bounced, splashed, all with those tall things doing their magic.

    "I have to turn" in the middle of this the captain shifts over pulls the ropes, messes with the sails, and shifts to the other side. I never knew which way the the wind was coming from, though we were sailing, inexplicably, upwind.

    All the time I was thinking how to improve this system. It is all manual, shifting from side to side, unlocking the sails, adjusting them, using the rudder. Surely there should be seats? Maybe a shorter sail would prevent tipping over, could we have a Sneakeasy with a short square sail or set of them that you could sit down and calmly dial in from the cockpit? Is this progress or are we in the stone age, so to speak.

    A very similar ride to mine
     

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  5. slboatdesing
    Joined: Aug 2022
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    Location: Maldives

    slboatdesing Senior Member

    So what does this all mean for my design?

    First of all, this is for lakes and sheltered waters (Category D). Open water with its winds and waves, not to mention getting safely back in shore, and having enough fuel to do it, is too much of a complication. Water canoe territory for sure.

    33 knots is simply too fast for me, maybe its my age, but cruising at 7 knots or less for the initial prototypes is good.
    An electric Sneakeasy in the lagoon environment I show in the catamaran picture would make my day, actually a few hours out there would pass in no time. 1 knot, no, 2 knots to counter the wind and current will be sufficient. I might even have a beer, though I never drink the stuff. The environment is safe enough, with a 1 metre to 1.5 metre depth depending on tides first time kayak paddlers around.

    I would even paddle a Sneakeasy.

    Interestingly enough, the resort uses electric buggies with 6 x 12 V or 8V batteries under the rear seat and charges in 8 hours, runs half the day with it. 6 batteries at 40kg each. Wow. But the concept is beginning to crystalize.

    If it is parked at a resort length wont matter. There is a water scooter but no jet boat. I get smiles when I ask about jet boats. The local place had one but sold it sometime ago, cost about the same to rent as a jetski. Too bad.
     

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  6. slboatdesing
    Joined: Aug 2022
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    Location: Maldives

    slboatdesing Senior Member

    It may be better to use a jetski hull, jet drive and convert it to a boat.

    What are the dimensions of the jetski?

    Generally speaking, the dimensions of jet skis currently in production are as follows:
    • Length: 80-140 inches
    • Width: 26-50 inches
    Length 2.03 m to 3.56m
    Width: 0.66 to 1.27m


    The jetskis I have seen are about 10 ft by 4 ft, so let's take that dimension, 3 m by 1.2 m. Compared to the modified boat design, the jetski planform should be just enough for two persons side by side and the electric motor and batteries.

    A used hull with the compressor and drive intact would be nice.
     

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  7. Flotation
    Joined: Jan 2020
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    Location: Canada

    Flotation Senior Member

    In your first thread you explained how you want your water craft to have a steering wheel as it makes you feel more comfortable when handling a boat.

    Other requirements that continue to pop up are low cost and portability. In your more recent posts it has become clear you are gaining experience on how different boats behave and even went sailing on a catamaran, describing how magical it was.

    Perhaps the time has come to reevaluate the steering wheel requirement. A wheel does not make a boat more easy to handle, it will make it "feel" more like a car but boats are not cars and behave very differently. I think most more experienced boaters will agree steering wheels make a small boat more hard to handle compared to a simple rudder or outboard tiller.

    A canoe with outrigger, like i proposed in the first page from this thread can be portable and is easy to steer with a trolling motor hanging over the side. Picture from the canoe on the first page:

    [​IMG]
    These outriggers are very cheap and can be fitted to generic canoes with a some small modifications they also are not very hard to make yourself.
    Single Outrigger Kit for Swagman Canoe made in Australia by Australis Canoes and Kayaks https://www.canoes.com.au/index.php?dispatch=products.view&product_id=228#

    Another example, with trolling motor:
    [​IMG]
    A bigger example can be found on this page:
    Solar-powered canoeing - Bush 'n Beach Fishing Magazine https://bnbfishing.com.au/solar-powered-canoeing/

    A canoe with an outrigger is only one step away from a sailing proa:
    [​IMG]
    [​IMG]
    [​IMG]
    Many variants are show here (technically not proa's but that's a different story):
    tackingoutrigger.com -- tacking outrigger sailing canoes https://www.tackingoutrigger.com/index2.html
    This way you can have a cheap portable electric boat with the option to go sailing,
     
    Last edited: Sep 25, 2022 at 9:50 AM
  8. Flotation
    Joined: Jan 2020
    Posts: 165
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    Location: Canada

    Flotation Senior Member

    To expand a little on the boat with outrigger idea: a non planing boat has to be long and thin to go through the water with little resistance. But long an thin boats are unstable and tip over easily. That's why catamarans exist. Two long and thin hulls that together make a wide hull for stability.

    Think of an outrigger boat as a catamaran with one big and a small hull. The latter can be small as it's only there for extra stability. It saves weight and building cost as the 1 + 1/3 hull of an outrigger is lighter and cheaper than the 1 + 1 hull of a catamaran.

    Outriggers with comfy trampolines also exist. It's not hard to imagine a couple of side by side beach chairs on them, if that's important.
    [​IMG]
    Halfway down this page there's a picture of how the above boat fits on a car:
    tackingoutrigger.com outrigger 16 https://www.tackingoutrigger.com/outrigger16.html
     
  9. slboatdesing
    Joined: Aug 2022
    Posts: 116
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    Location: Maldives

    slboatdesing Senior Member

    Well yes, I have been thinking of either a sailing boat, fitting sail to a canoe, or a trolling motor: this is all acceptable.
    The main limitation right now is the water depth - only jetskis are allowed since they have no propeller. If only there was a trolling jet motor.

    Next step is to look at buying and adding a sail to the Kayak, if conditions permit sailing.

    I have also got a quotation for a locally made boat for less than $ 700 brand new. An used one will be less.
    Next I have to find someone to install a propeller in a tube and an electric motor and battery. It will mean cutting
    out the bottom of the boat.

    Jetski parts etc are too expensive and out of reach, so that idea is out.
     

  10. Flotation
    Joined: Jan 2020
    Posts: 165
    Likes: 29, Points: 28
    Location: Canada

    Flotation Senior Member

    Not necessarily, you can side mount a trolling motor. The one i posted earlier is also side mounted. Below are some examples, something like this is easy to DIY:
    https://activelyoutdoor.com/how-to-mount-a-trolling-motor-on-a-kayak/
    As an added benefit it will make steering more comfortable.
    When you Google trolling motor propeller guard you'll see a whole lot of options are available to protect your prop but also the environment, some of them not hard to DIY, just one example:
    https://www.amazon.com/BXI-Propeller-Protector-Anti-Winding-Protective/dp/B075PQ5M5N
     
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