Hi all. I am considering which motor to get for my PocketShip. I have had some good feedback on here about the ePropulsion motors, but I’m curious what people think.
My questions are:
Long or short shaft?
How to mount it - purchase a bracket, or make something?
Which motor? Are there makes other than ePropulsion which are recommended?
Is range a serious issue, and does carrying a spare battery resolve this?
Thanks, and greetings from the UK.
All good questions. Much depends on how you use your boat. Will the motor just be to get you in and out of the marina or will you use it transit from A-B? Generally, two batteries = twice the range. It might be worth a phone call to Tiny Boat Nation or another electric motor store. You can tell them the specs on your boat and what you plan to do and they can really help you nail it down.
That depends on where exactly on the transom you mount the bracket. The only example I could quickly find is a website Sean’s Pocketship that uses a long shaft. I don’t remember what size the prototype Pocketship uses.
John Harris posted about building a fiberglass bracket here. In a personal conversation he later told me that while it worked very well, was more than strong enough to support any reasonable motor for the Pocketship and would never corrode or rust, it was more expensive and more effort than just buying an off-the-shelf motor bracket.
Torqeedo is a very reputable brand. The only reasons I went with ePropulsion instead of Torqeedo was weight and local availability. All of their motors had a week-plus delivery time, even from local dealers and I needed one in 3 days. The ones with integrated batteries all weighed more than the maximum weight specified for my boat. (I wanted an integrated battery because I wanted to be able to quickly remove the whole setup from my transom and stow it in the cabin without disconnecting a bunch of wires and cables.)
Jon’s response is correct - it all depends on how you use it. Running full power typically gives you less than 1/2 the range of running at low power. Full throttle speed is typically less than double low power speed. The take-away is that full power should be reserved for situations where you need it to fight wind and tide. For boats with efficient hulls, like Pocketship, the lower power settings will give you the same speed as sailing unless you have a strong headwind and/or tide.
Even with my tiny eLite motor I’ve never used more than 13% of its capacity at a time so far. I only use it to get in and out of my slip and the surrounding docks (the space is too restricted for oars) and to get out to the river when the winds are unfavorable (just tacking is impossible with certain wind directions when the tide is below a certain level).
A second battery is the equivalent of a second can of gas. The only trick is changing it without dropping anything expensive in the drink.
Hope this helps,
Laszlo
I’m blessed to have Tiny Boat Nation just 4 hours drive. I’m considering making an appointment and trailering my SW Dory down there once the motor well is installed. Let them advise me on shaft length etc.
The epropulsion battery floats!
If you have a house battery you can recharge while sailing, though the 12V charger is slow.
At mid speed , I’d say you can go 5-10 miles. I’ve never needed to go more than a mile or two and don’t think I ever went below 75%.
I have the long shaft. I use an adjustable motor mount that can be raised, but I find just flipping the motor up is sufficient.
It to me a while to figure out a good placement. I can take pictures and measurements next time I’m at the boat.
And if you go over 5 or 6 knots (ha!) the motor regens !
Spirit One battery floats, Spirit Two battery does not. Love that regen feature though I wonder if I’ll ever sail fast enough for it to work.
Is that motor in a raised position and gets dropped down for use? I’m trying to work out how such a motor will fit on back of the boat I’m building
I think that’s the raised position. However, I found I don’t need to use the raise/lower feature of the bracket. Just tilting the motor up from the down position gets the prop out of the water.
I can take more photos or measurements, if you like, next time I get down to the boat.
I got down to the boat yesterday and took some photos of the setup I’m using. The top center of the mount is 14” from the centerline and 6.5” down from where the transom ‘breaks’ inward. As I mentioned, I leave the mount in the position shown as it is deep enough for motoring and high enough to get the prop out of the water when the motor is tilted up. I bought the Evo Remote and keep the motor fixed; using the rudder to steer. I used elevator bolts to attach the mount as spreads the force and makes a clean look on the inside of the boat (top two bolts are above the hatch area).
Many thanks for this Steve. You have done exactly what I have been planning to do with my PocketShip - now I know what to do! Which model ePropulsion do you have?
Spirit 1.0 Evo-L
I also did some speed/range tests . These were mostly heading into a ~8 knot wind. I had also run the motor about 1/2 hour already:
Note that at the low setting I could not get the boat to turn into the wind, so it would only be of use in a calm.
That’s really useful Steve. More so than the info provided by the vendors! Many thanks.
The motor mount location was hard won. I wanted it close to center but not hit the rudder at full swing. I also wanted to keep it as shallow as possible.
Outside of data collection I had a wonderful sail yesterday. Pocketship is such a nice boat. I have to admit I’m a bit of a coward though. The rule of thumb I’ve seen is reef at 15 knots. I find one has to really stay on their toes for that. I was in 8-12 knot winds with the first reef in and it was very comfortable, easy sailing. Still made 3-4 knots.
Thanks again. I will use the same measurements when I get to fit my motor. By the way - what are elevator bolts? And which brand of motor mount did you choose? Thank you!!!
They are like carriage bolts but with a much larger and flatter head. McMaster has them in stainless. I also used them to attach the tabernacle to the cabin. Probably overkill on the motor mount, though probably appropriate for the tabernacle.
I went looking through my file and it looks like it was a FiveOceans, but I don’t think they make it anymore. In any case, I think you can get by with a fixed bracket. I’d say mine puts the motor out about 12” from the transom.
If you buy a motor with tiller steering you will need to check clearances. You might need a bracket that can be raised for that. I bought the remote version so there’s no tiller to deal with.
You might also check out the fiberglass motor mount John Harris made for the original Pocketship:
Fiberglass bracket
Thank you Steve. I didn’t realise you could buy a ‘tiller-free’ version of the motor. Does not mean you can’t steer with it, even if you wanted to?
I’m thinking of making my own bracket. It can’t be that hard, and I will get exactly what I want.
It’s the Spirit 1.0 Evo Remote. It’s actually designed for remote steering (via cable system) but I keep it locked straight. I think the biggest advantage is there is no tiller arm to get in the way when you tilt the motor up so it gives more leeway in the motor mount. The speed control is remote , which I also like.
I suppose you could fashion a tiller of some kind to attach to it just to steer but then you have to be sure the prop won’t hit the rudder.
Sometimes I decide to do things just because they are different. I like to experiment. I haven’t seen this setup before but it made sense to me and I think it works well. But consider the tiller style too and see what you think. It would be good to see other solutions.
Here’s a crazy thought. Use the remote version and have a removable link between the rudder and the motor so they turn together. It would allow them to be closer together and multiply the turning force (though my current setup turns ok). I might have to try this.
For best performance they can’t be parallel since the motor is offset from the centerline and the rudder isn’t. The motor will try to turn the boat (to port, as pictured). The rudder will have to be turned to counteract that, which results in drag. If the boat is moving slowly enough there may not be enough steerage way to correct for the offset motor, resulting in a slow circular course.
Generally, you need to keep the motor’s thrust line aligned with the boat’s center of gravity for proper steering, whether linked to the rudder or not. So for that fixed remote motor it would be advantageous to have it slightly angled to port instead of straight. That would let the rudder stay pointed straight and reduce drag. The required angle will change as the throttle setting changes.
Linking the two makes it more complicated since the rudder will also gain and lose effectiveness as the speed through the water and the rudder’s angle of attack changes. That will result in the motor/rudder angle needing to continually change.
Again, this is for best theoretical performance. You could just leave the angles fixed and accept the higher drag and battery drain as the price of simplicity.
Laszlo
