Electric outboard drive for small cruisers

  • 25 May 2020 15:01
    Reply # 8991391 on 8809939

    Now I'm confused.

    I got another breaker, rated at 150A and took it aboard - only to find the one that I'd already installed was rated at 150A, when I could get a good look at it. So why did it trip?

    I also took aboard a 100A ammeter. I chose this one because the readout is waterproof, and just needs a 29mm holesaw through the cockpit side to install it. That part was easy. The shunt took a little bit of wrestling with the heavy cables, but I got it done. However, it's supposed to have a "bright, waterproof, daylight readable OLED screen" but I can barely see it on a sunny day, even with some shade over it.

    Anyway, I was able to get a reading on the mooring, not going right up to full throttle for more than a few seconds. It would seem that 50A - 60A is enough for all normal purposes of moving in and out of harbour. That's 1250 - 1500W, or up to about 2HP. Quick bursts of full throttle for manoeuvres should be safe enough, as the ammeter is rated at 110A intermittent and 175A for 30 seconds. The readout goes up to 99.9A and then a meaningless reading, but I'm convinced that the full throttle current is near enough to 105A. So why did a 150A breaker trip??

  • 24 May 2020 20:50
    Reply # 8990425 on 8809939

    While in the process of removing the backstay mounts it dawned on me that they should definitely be converted to outboard brackets!


    They should be strong enough (even though they're designed for upward pull) and are quite optimally placed for an outboard mount. With the motor completely lowered the propeller slightly touches the rudder when the tiller is all the way to port, so will add some sort of stopper to prevent accidents. I can comfortably reach the throttle (in its extended position) when sitting at the tiller. With my Fingal I had to hang off the transom to reach the controls so this is kind of a luxury. 

    I just need to figure out how to attach a vertical plank down from the aftmost support. If it's easy enough I'll make a mirror of it for the other side. Maybe a (double) wooden plank attached to (each side of) the aftmost bar with a stainless rod/tube attached from the bottom of the plank to the bottom of the middle bar. It would also be nice if the plank could be easily removed as it's not particularly efficient hydrodynamically speaking, when sailing on her ear like these boats like doing.

    I didn't actually check how much the motor can safely turn with the rudder centered, I just (wrongly) assumed I'd always keep the outboard centered. When maneuvering in harbours though this would be very welcome as Tua-Tua reverses like a dog. Will have a look at this tomorrow.

    Once again David I'm glad you're out there making mistakes so I don't have to - I will get a 150A breaker as well. 

  • 20 May 2020 12:58
    Reply # 8981400 on 8809939

    Motor trials, on a nice sunny day, almost calm, with almost flat water in Ravenglass harbour. Aboard at HW. I lowered the motor to its fullest extent, as if for a heeled or pitching situation. Then I motored up and down the harbour at full throttle. That gave me 4.2 knots in a straight line, decreasing to 3 knots in a tight turn. The motor hum was quite loud, but not unpleasantly so.

    But 10 minutes of full throttle caused the 100A circuit breaker to trip. Clearly, the motor must have been drawing the full 105A, as advertised. So I had to drift for a few minutes before the breaker cooled enough to re-engage. Not good. I will have to change it for a 150A breaker.

  • 14 May 2020 15:06
    Reply # 8968623 on 8809939

    Yay! the big solar panel is now aboard, mounted and connected up.

    Both ends are supported by 2in x 1in aluminium channel bearers. For the forward end, I was able to re-use the posts that supported the original 100w panel. For the after end, I made a hatch garage, which was needed in any case, and bolted the channel onto that.

    On a sunny day, with the battery almost full, the panel was generating 270W:  6.5A @ 42V coming from the panel to the controller, 9.8A @ 27.5V going from the controller into the battery, so the controller is doing as advertised.

    3 files
  • 11 May 2020 13:35
    Reply # 8960787 on 8809939

    I'm thinking that the way these electric outboards will slide up and down in their mounting might make motor sailing to windward easier, if the bracket on the boat is low enough. The outboard can simply be adjusted in height when you tack.

    Yeah it's possible that one mount might work for both tacks, depending on how much the mounting position moves within the targeted range of heeling angles, although with a bracket on each side I could potentially get away with using cheaper (and stronger) non-adjustable brackets.

    The lower bracket will also reduce the leverage on the surface of the hull, by reducing the distance between prop and bracket.

    This is a good point. But it might also speak in favour of using two brackets (if the adjustment range isn't long enough to use only one, safely). Will go and make some measurements later this week, since right now it's snowing... :(

  • 10 May 2020 14:51
    Reply # 8959046 on 8809939

    I'm beginning to think that the cable connector as supplied with the Haswing is not very convenient, especially for moving the motor from side to side or stowing it below. It's difficult to install it in the boat in a waterproof manner. Perhaps Dinze quick disconnect welding cable connectors would be better, with panel mount male (-) and female (+) in the cockpit, and female (-) and male (+) on the ends of the motor cables.

  • 10 May 2020 12:25
    Reply # 8958859 on 8809939

    I'm thinking that the way these electric outboards will slide up and down in their mounting might make motor sailing to windward easier, if the bracket on the boat is low enough. The outboard can simply be adjusted in height when you tack. The lower bracket will also reduce the leverage on the surface of the hull, by reducing the distance between prop and bracket.

    Last modified: 10 May 2020 12:27 | Anonymous member
  • 10 May 2020 11:38
    Reply # 8958809 on 8809939

    I'm planning on having an outboard bracket mounted on each side of the stern, similar placement to this (hard to find pictures of sailboats), just forward enough to not interfere with the rudder:

    When not in use it would be mounted on the pushpit and on passage down below.

    One on each side so that I have the option to motorsail. I like the idea of feeding the 2-300 watts coming from the solar panels directly to the motor (free power!) for a very nice speed boost in calm conditions as well as improved pointing ability. And for the ability to motorsail under less ideal conditions, for example trying to make entry before nightfall in a chop, keeping the motor properly on the leeward side (its adjustability is excellent btw).

    With a stinknoise engine I would never consider motorsailing unless I really had to but now it will open up a new range of possibilities.

    The arrangement won't be very pretty, but...

  • 10 May 2020 08:16
    Reply # 8958729 on 8809939

    How are you mounting the Haswing on a double ender, Oscar?

  • 09 May 2020 17:52
    Reply # 8957915 on 8842512
    David wrote:

    I put it in place. Problem solved. The prop now whizzes round. It's quite noisy for an electric drive (out of the water), but nowhere near as noisy as a petrol outboard, of course. I think I'll be reassured if I can hear it going, and how fast. If it were completely silent, that might be too little information.

    Having read this feedback a while back I was positively surprised to find that it's not really that noisy, in my opinion! Did a quick test with two 60Ah 12V lead-acid batteries so didn't want to crank it up that much but I'm very happy overall thus far. It seems decently built and I was happy when I noticed the throttle handle is "telescope-extendable" by some 15-20 cm.

    Last modified: 09 May 2020 17:52 | Anonymous member
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