Category: Electric propulsion

Claude Desjardins arrived yesterday morning with a Torqeedo Cruise 4.0 and in a couple of hours we cobbled together a suitable bracket to mount it on.  Its size is sufficiently different from the Epod to mean the well opening would have to be rebuilt to accommodate it. But for this test we easily manouvred it through the gap.  At 18kg its about half the weight of the Epod and hey, you know how anal I am about weight, so this is definitely a plus.

Also on board were a motley assortment of characters from the boatyard and beyond. As well as the usual suspects, Steve and Sean, we also had some fellow electric boat afficionados in Tarci and two Bryans, and to ride shotgun for us, Claude’s son, Nicholas came along.

We pulled gently away from the dock and then ramped up the power to see what it would do at full throttle. We got her up to 5.3 knots with a little current (maybe half a knot) against us. This is more than I ever saw from the Epod (but mind you I had lost confidence and wasn’t game to give it full throttle for more than a moment when manouvring).  And this 5.3 knots is with 8 people on board.

Coming back down soon after, we topped out at 6.5 knots.  If we average these, we should expect top speed in still water to be 5.9 knots.

At maximum power it is using 4400 watts, or 90 amps from the batteries. At this power I could go for maybe two hours.  But that extra few knots of speed costs a lot in power consumption.  At a lower speed of 3.4 knots it only draws 900 watts, or 17 amps. And at this speed I could travel for over ten hours.

You should see the helm control for the Torqeedo – it has a great LCD readout showing speed, (it has its own GPS built in), power being used, battery state (such as voltage but you can choose from other options), and range left in the batteries at this speed.

For example, one of the readings showed power consumption as 500 watts, speed at 3.2 knots, and available range at this speed: 56 miles.  So its a really useful tool to have right at your finger tips.

I compared this to the Link 10 battery monitor and we found an excellent correlation. At the end of the run the battery capacity remaining, as reported by the Torqeedo controller was 84%. According to the Link 10 we had used 32 amphours, which out of a total of 200, is 16% – which means 84% remaining.

In this test we went up the river and back to the boatyard, then kept going downriver to the shallows, then back up to Monty’s, and then a few loops before we docked.  And used 32 amphours. When I first left Monty’s with the Epod, it used 50 amphours to get out of the river. This was all low speed work, and probably about half the distance we went in the Torqeedo.  There are other variables of course but its clear that the Torqeedo is more efficient than the Epod – and maybe around twice as efficient.  This effectively doubles my battery capacity.

We tried an emergency stop – that is we got her up to full speed of 5.3 knots and then put the motor into full power astern.  This was perhaps the most disappointing aspect of the Torqeedo. At full astern its maximum power demand was 1300 watts, and the slowing effect could only be described as gentle. The specs on the Torqeedo show that is limited to 50% power in reverse, but we only saw about a 30%, and that’s how it felt too.

Compare this to the Epod which has full power available in reverse and that is useful for manouvring.

The Torqeedo unit is steerable. Even though we didn’t test this on the day, I can see how I could link it to the spectra steering lines so that the motor would steer with the rudder and that would be great for close quarters manouvring.

I have some detailed figures of power and speed and if you want to see them, let me know.

I’m leaning strongly to the Torqeedo, but I’m choking on having to throw away the $8000 I’ve spent so far on the Epod.  The Torqeedo is very well engineered and I’d have confidence that it would work when I need it (well, what else would you expect, after all, it is German).  And that’s probably going to be the deciding factor, because even though I can see how to fix the Epod in such a way that it would be reliable, I’ve just about had a enough of it.

And hey, its arguably now the best engineered Epod available, so perhaps someone will buy it from me…

Last week I was about to motor upriver to do another battery discharge test – but I found something suspicious about the motor and stripped it down to check.  Water had been getting in – in very small amounts but enough to cause corrosion.  This is worrying in a electric motor and is possibly the last straw for this camel. There’s been an ongoing series of problems with the Epod motor which continue to delay my sailing.

It is now two years since I ordered the Epod and still its not ready to go.  To begin with it took about twelve months to take delivery of it, and now another twelve months to troubleshoot it.  Of course there’ve been other boat projects to do, and other things which have caused delays, but a prime delayer has been the motor.

I’m now at a cross-roads in more ways than one. Firstly there’s whether I should even bother to persevere with this motor at all.  But that is really just a practical matter which will sort itself out.

Of deeper import is what does this all mean for my life journey? So many things have conspired to delay me from sailing, from leaving this area. Is there an esoteric message here for me? I’ll ponder on it and see what comes.

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For those who have a technical interest in my projects, read on. I’ll describe the details of the problem. But for others, take heed, techno-babble follows.

After recharging the batteries I was ready to do another discharge test last week when I checked the epod sump before going upriver.  There’s a plastic tube that you suck on to see if there’s any water in the bottom of the Epod. Well, nothing happened – that is I couldn’t suck anything – the tube was blocked somehow.

So I pulled the motor out (easy enough because its on a carriage) and stripped it down again.  I found aluminium corrosion in the bottom – you know that gooey gel type corrosion – and it had blocked the tube.  Well, the tube did its job but in a different way to expected.

There had been water in the motor at some time but it was dry now – a little condensation around but no water laying there.  The last use was in the flood about two weeks ago – and after using it I had as usual sucked on the tube but found nothing.

But some water has been getting in. Clearly not enough to even be sucked up in the tube, but enough to cause corrosion.  All the electricals are fine – the brushes, commutator and armature are all above any water that got in, and are in fine condition.

I pulled off both end bells looking for the point of ingress.  On the brush-end there was a drip line of corrosion showing where water had got in past the o-ring and dripped down the inside face of the end bell. At this end there was gritty dust of corrosion – a different type to the soft gel like corrosion at the otehr end.  The prop end, the end with the tube, is slightly lower and the water gathered at this end.

I had pulled the ends bells off when I had a shorting out of the power cables some time ago – see a previous post about that.  I expect the failure of the o-ring seal is to do with the way I put it back together.  Even though I was very careful, I did reuse the o-ring – which looked perfectly fine.  But I’ve now been told this is not good practise and a new o-ring should always be used.

In my search for the source of water entry I had also pulled the prop-end bearing out of the end bell.  I found water here between the seal and the bearing. There was a glob of water about the size of a pea. The bearing was still ok, although stiffer than what I expected. This bearing and seal are as they came from the factory.  The presence of water here is worrying and the bearing would have failed sooner or later.  So in a way I was lucky to have found that problem now.

The bearing at the prop end is retained with a galavanised steel washer which is screwed to the end-bell with galvanised screws.  The screws and the washer are rusted. The through boats that hold the end bells together are also rusted on the threads. Probably from moisture condensing there.

I’m concerned about the mixture of disimilar metals in the epod. The aluminium end bells have corroded and some of the steel items have corroded.

As I contemplate rebuilding the epod again I’m considering having the end bells rebuilt out of stainless steel and using stainless steel bolts and washers, and not having any aluminium at all.  In this way even if moisture does get in, it won’t be harming. It’ll cost about $1000 to have the parts remade in Stainless Steel.

I’ve also checking out another electric motor from Germany and which has been available in small sizes for a while now.  They’ve just released a bigger version that would suit my boat. There’s an agent here in Australia – and only an hour away from here.  He’s agreed to bring a motor down to Current Sunshine later this week so we can do some tests and see how powerful it is, and how much current in draws. The downside is that its pricey – at over 6 grand its a big step for me after investing so much time and money into the other one.  As well it doesn’t have regen capability.

Anyway, stay tuned and I’ll let you know how it is.

(last Friday) Sleep was patchy, every now and again a log calling for my attention.

Dawn broke sopping with heavy rain and gusty E/NE wind blowing water into the back of the cabin. In the early hours a plan had formed, and so I started re-arranging some of the lines in readiness.  I’d decided to leave the jetty.

(flood photos courtesy of Chris of the double-ender)

Current Sunshine was vulnerable here – she’s so wide and that means her main hull is out in the stronger current, more subject to flotsam catching on her, and with her float even wider, offering to trap any boat that comes drifting by.

I woke Steve and Miki to help me – but it turns out they were already awake.  So they leant a hand to re-adjust the lines, and set up for moving into the little bay thats formed by the cutting for the slipway. The plan was to just loosen the lines bit by bit and let her go downstream towards the bay. Then we’d just ease her into the protected backwater of the ramp.

Inglelooseberg was dragging.  A big steel schooner dragging right towards Current Sunshine. Oh no. Quick, let the lines now. But no, she’s dragging too fast she’ll be on us in half a minute. I get the knife I’ll have to cut the lines. But even that is not quick enough. She’s on us already sticks her fat arse between the main hull and the outer float.

I can see the float being torn off in the next seconds.  She’s about to be destroyed.

But the big schooner stops in her tracks just as Current Sunshine starts creaking and groaning. I despair at what’s about to happen. But we have been given a second chance. By now there’s plenty of hands – others have seen whats happening. We take a moment to figure which lines to cut or release so she can swing out of the way of Ingleloosenberg and into the bay.

We cut some lines and motor her backwards quickly, with the inside float still tethered she should swing into the bay. But Ingleloosenberg is coming with her. We’re trapped. Steve notices another line that needs to be cut. Others secure Loosenberg so she stops. Finally Current Sunshine’s free and her turning circle just makes it into the protected bay of the slipway ramp.