Propeller trials on SeaEagle kayak

Which propeller should you use on the 1003?  Did you even know that you have a choice?

The standard prop that comes with the 1003 is a two-bladed one that is optimised for speed and power for the vessel that Torqeedo expects most users to have.  Thats a result of their market research and really, its what the average user would choose.  Common uses are to drive dinghy or a small sailboat.  And for most of the boats in these categories the two-bladed prop would be the best choice.

But we were wondering how would it be for an easily driven hull such as the SeaEagle kayak, which you may have seen in previous blog entries here and here?  So on a recent Sunday afternoon David, the owner of the SeaEagle and I did some tests to judge how the three-bladed prop normally found on the 801 would perform on the 1003.

These motors have the same drive shaft details which means the propellers can be swapped easily using just a socket spanner.

The day planned for the trials dawned with a westerly gale in full force so we delayed our tests till the afternoon when the wind was expected to be lighter.  At the time of testing the wind was around 10-15 knots and we tested with the wind on the beam to minimise its influence, and we stayed in Crystal Bay in front of my office where it is well protected.

We did a pass in each direction as well, just to minimise any downwind assistance we may have inadvertently picked up by not being exactly beam on.  So here’s the results plotted up and curve fitted to make it easy to compare the two sets of data.

The blue line is the 3 bladed prop from the 801

You can see from this that the 3 bladed prop is easily better for this boat – its almost a knot faster going from a top speed of 5.4 knot with the standard prop to 6.3 knots with the 3 blader.

Do you notice how it effects the power demand? See that at a particular speed the 801 prop uses less power to reach the same speed.  So its clear from this that if you have a SeaEagle kayak you’d choose to get a spare prop for the 801, and fit it to your 1003.

I expect that this same advice would apply if you have a 1003 on any easily driven hull.  And one way of telling how easily driven it is is to look at the maximum wattage when you have the motor at full power.  If full power is less than 1000 watts, chances are that the propeller is runnning at full revs, and that is the limiting measure. That is, the motor has ‘red-lined’ without having to deliver full power.  So it has more power ‘up its sleeve’ and its this power that we can use to drive a higher pitched prop such as the one from the 801.

As you can see from the chart, with the 2 bladed prop, the maximum power demand is a little over 900 watts, whereas the maximum for the 3 bladed prop is over 1100 watts. Its my guess that for the 2 bladed prop, maximum revs is reached, and for the 3 bladed prop maximum power is reached.

These results match the calculations you might do based on prop pitch. If you delve into the specifications you’ll see that the three-bladed prop has a pitch of 10 inches, and the two bladed prop has a pitch of 8 inches.  Thats 25% more pitch – so we’d expect it might be able to go faster, provided the motor has the power to spin this prop.  And because we know its its not demanding full power for the standard prop,we know it does have some spare power available.

How much faster can it go? What about the speed prop thats available for the Cruise 4? David and I have been speculating about an adaptor to be able to fit the speed prop from the Cruise 4….  but, hey, thats a test for another lazy Sunday afternoon.


  1. On a related topic: I have an 801 base travel…do you think the newer high-speed propeller for the 4.0 cruise model would increase the top speed over the traditional 3-blade prop (or would it even fit). I use it on a very light boat (35kg) and the 801 has more than enough torque…just wondering if there might be a small benefit to trying the newer prop if it would fit! Enjoy your blog…after using the Torqeedo 801 I ditched my old trolling motor, and have become a bit of a Torqeedo junkie… -DC

    • Hi Dave,

      I think it would be worth trying but you’ll have to figure out some kind of adaptor to use the speed prop – it has a larger diameter shear pin and also is meant for a larger diameter shaft. David and I plan to try it though on his kayak in a few weeks. (He’s leaving on adventures in a few days and it will be a couple of weeks till he’s back). When we do it I’ll put up photos and info of how we got the prop to fit – and I think it will be fairly easy. You might want to hold out until we do those tests and see what we come up with.

      Can you get a reading of how many amps your base travel is pulling when its running at full power? Then you could, say, drag a bucket, and see how much if any it increased the amps – if the amps increased that should be an indication that top speed is limited by the revs of the motor, and not the maximum power. Then you’d have a good chance that the speed prop would give you more speed.



  2. …thanks for the reply Chris! I’m not sure how to measure the #amps the motor is pulling at full power, but I figure the motor revs are the limiting factor since I have tried the motor on: a streamlined canoe with no additional load, a fully-loaded canoe with gear + 2 people, a light boat with much wider beam with gear + 2 people…and they all top out at the same speed (5.0-5.2kts. depending on wind, current, etc.). Just based on that alone, it seems that prop revs would be the limiting factor on speed, and the motor can actually do more.

    I’ll be looking for your experiment with the speed prop…interesting stuff! Maybe the folks at Torqeedo could produce two props for each motor…one that maximizes pulling power, and another that maximizes speed…

    Experimenting with these kinds of things might make an already viable substitute for a small gas outboard even more attractive.


    • Hi Dave,

      I think you’re right – from your observations of different loadings it seems quite likely you’ll get more speed with a higher pitched prop. Stay tuned for our experiments with the speed prop.

      If we can get some good results here perhaps it will encourage Torqeedo to follow your suggestion.


  3. Hey Chris,

    A quick follow-up: would the Cruise 2.0 accept the high speed prop without modification? That could be an interesting option for light boats too.

    • Hi Dave – yep the Cruise 2, both the R version and the current tiller version, take the speed prop as is. Older tiller version, prior to serial number 5000 had a different hub. Because it needs only 24v its minimum battery pack can be lighter than the Cruise 4, and so it could be a good match for lighter boats as you suggest.

  4. Ever get around to trying the Cruise 4 prop on a 1003?

    Also, are there any plans to make a basetravel version of the 1003, for external battery banks?


    • Hi Neil,

      No – didn’t get to test the sped prop on the 1003. I suspect now though that it won’t be any advantage unless we can find a really slippery boat, perhaps like a rowing shell, and would be easy enough tp push at speed.

      And I’ve just come from training with Torqeedo in Germany and asked about this very thing. And yes it is planned but its not on the immediate agenda, and just when it will be done is not clear.

  5. Hi,

    I am planning to buy a Torqeedo for my kayak and, even if Torqeedo Ultralight is the one proposed for kayaks, I am more interested in the 1003

    I saw you did some interesting comparisons between propellers, could you also estimate how 1003 would act on a kayak versus the Ultralight (in terms of range and speed)?

    The kayak is a trimaran actually, Hobie Tandem Island, 80kg empty but with 2 people and gear it will have 300-350kg


    • Hi Tudor,

      Cool, I like trimarans 🙂

      I haven’t tested a 1003 on a kayak other than the Sea Eagle. The Hobie has what looks to be a better hull form than the Sea Eagle so I’m confident you’ll see higher speeds when using a 1003 on it. It could be similar to the Old Town Canoe and perhaps even better. In the tests of the Old Town Canoe we saw a maximum of 12.6 and that was well loaded. So with just two on board you could see 13 or 14 km/hr. I’m also sure that you’ll be better off running the 3-bladed prop rather than the standard two bladed prop. The three-bladed prop has a higher pitch to allow you to reach a higher top speed.

      As for range, as long as you can control the impulse to open the throttle and travel at low wattages, you’ll be able to see a range of about 60% more by using the 1003. Its battery is 60% larger, and providing your power is below 400 watts (the maximum for the ultralight) you see proportionally more range. And you can use a solar panel with 1003 to extend the range even more.



  6. Hi from Germany, we have read about your trial with the props on the travel 1003.
    we use a 1003 with the 503-prop on a small catamaran made of extruded polystyrene.
    13 km/h (7 knots) with the plattform (without ships sides) and one person.
    if you want, look here:

    Tom Sawyer

    • Hi Tom,

      Great video! I love your boat—it is a nice design and slips through the water really easily. Easy to put on your car and looks great too. When are you going to add solar panels to the bimini?

      Thanks for the news.



  7. Hi Chris,

    Just wondering if you ever tried the cruise prop on the travel 1003?
    Very keen to buy a travel 1003 but just need a bit more speed to make it a viable option.
    Its good to see a few more kmh can be gained with the 503 and 801 props.
    If one of the cruise props can gain a bit more then you are on to a winner.

    • Hi Kendall,

      I’ve been meaning to try that sometime but haven’t gotten around to it yet 🙂 What we need though is a really easily driven boat to try it, maybe something like a Hobie Wave. We’d have to adapt one of the fast Cruise props so that it can be attached to the 1003 drive shaft which is a different diameter. One way to tell beforehand whether we’re likely to get a better result is to find a boat that we think might do it, and run it with the 801 prop on and see how many watts it is pulling at top speed. If its less than full power then thats an indicator that we could do better with a faster prop.

      Do you have a candidate boat in mind? I imagine a light boat on foils would be just the ticket…

      Cheers, chris

  8. Hi Chris,

    I really need a boat that can be transported on top of my car and stored easily in my shed so have been looking at portabotes etc and am waiting for more details of the Aussie Foldaboat which looks like a relatively slippery design for the type of hull it is. All up weight should be around 150kg including myself, travel 1003 and a bit of fishing gear. I know the folding boats will be no where as slippery as something like a Hobie Wave but considering the torque of the Torueedo, low weight of the boat and smooth inland waters I will usually be on, I’m confident there are gains to be had with the 503 prop but not so sure about one of the cruise props. Might be asking too much.
    I notice the 1003 and 503 are both available with 2 props each. Just wondering which 503 prop you used? The V8 or V9?

    cheers, Kendall

    • Hi Kendall,
      As the props are listed on the Torqeedo website, the two bladed prop that comes standard with the 1003 is the v9 and the three bladed prop that comes on the old 801 and the 503 is listed as v8. What we found on the SeaEagle is that the three bladed prop gives about a knot extra speed. Which implies some weirdness in the Torqeedo labelling of the these props as v8 and v9, which doesn’t match how they perform. To get back to basics the three bladed prop has a higher pitch of ten inches compared to the two bladed prop’s eight inches. So at a particular rpm the three bladed prop will be faster, provided there is enough power to drive it.

      As I have got to know the typical usage patterns with these motors I’m thinking that it probably doesn’t make a lot of difference which prop you choose. Chances are that you won’t be running much at full speed, and thats where there’s a difference. Because at full speed it will suck the power out of battery pretty quickly.So these motors tend to be used at low power settings, say around 100 t 150 watts so as to have plenty of range.

      With that in mind, perhaps it is worth getting the three bladed prop, but I’d think it highly unlikely to be worth tinkering with the faster props from the Cruise models.



  9. Whoops I mean Flatout-boats not foldaway-boats. The Flatout boat seems to be a superior design to other folding hulls such as foldaway of portabote. I’m guessing it might be the slipperiest.

    cheers, Kendall

  10. I have a 18 ft trimaran sailboat, weight about 500lbs and have been using a Torqeedo 503 for 4 years in salt water, but has been giving error codes (30) and since I don’t trust it I have ordered a 1003. Should I change the 2 blade prop with my old 3 blade. Top speed is 4.9 kts but I normally go 3 to 3.5 kts at half speed. I’m more interested in range.

    • My understanding from Torqeedo data is that the two-bladed prop is more efficient and so you should see more range with it. With such as easily driven boat you will probably get higher top speed with the three bladed prop. That will be easily tested when you get the 1003. When you get the new motor you might want test your old motor with the new battery and tiller (and vice versa) to judge which part is responsible for the E30. You may then get a sense of what needs to be repaired or serviced to have a backup.
      cheers, Chris

      • I’ve use the new T1003 two times and it is an improvement over the 503 in that I use a lower % of the battery since the battery has a lot more capacity. Top speed was 5.1 kts vs 4.9 with the 503 and 3 blade prop, but I started getting some vibration at full speed. At 3.3 kts which I usually run, it was using around 15 watts. I’m happy with the 2 blade knowing I have so much more range. My Garmin 76 GPS show the same speed as the Torqeedo. I’ll keep the 4 year old 503 as a back up or have an extra battery.

  11. The V8 prop is 8km/h at 720rpm
    the V9 prop is 9km/h at 1200rpm
    if you turn the V8 at 1200rpm you get 13Km/h

    • The V9 prop is 8.1 inch pitch and the V8 prop is 10.7 inch pitch. The ratio of these pitches is 1.3, so thats the extra speed you should get when changing from V9 to V8 on the 1003. That is, 9km x 1.3, which makes it 12 km/h. Not far different to what you figured.

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