Electric Boating

[jjeff]

Agree, nice looking motor, boat and don't forget the Santa cap
Unfortunately around here, our boating season is over, pretty much all lakes have a thin coating of ice, probably 4 months before we can start thinking about boating

 

[bobkart]

I don't know about boats, so what would be the effect of the angle and raising or lowering the motor--does it control the torque moment that is lifting the bow?

That's pretty much it: the bow will ride higher/lower when the motor is trimmed out/in, respectively. Trimmed 'out' means tipped up more (bottom away from the boat, towards the right in the earlier picture). You would typically trim the motor out to try to get more of the hull out of the water at speed (for reduced drag), then if it started to bounce up and down ('porpoising'), or just going slower, you'd want to trim it back in a bit. Trimming in can also be a response to rough water, softening the ride due to more of the hull in contact with the water.

There were likely more subtle effects in this case, like slightly lowering the propeller axis, and bringing the propeller slightly forward, thus closer to the structure under the middle rear of the deck that simulates what would be the hull on a monohull boat (providing a more stable water surface to the propeller).

EDIT: I see you were asking about vertical height changes, in addition to trim angle. You usually want as little of the motor in the water as you can get away with (to reduce drag). There is the effect you describe as well, and porpoising can result from the motor being mounted too low. But the more common problem is 'ventilation', which will occur due to the motor being mounted too high, allowing air to get sucked into the propeller. This issue is frequently and erroneously referred to as 'cavitation', but that's a different phenomenon, but with similar symptoms (propeller losing grip with the water).

 

[bobkart]

Most above-the-deck parts have been removed, in preparation for installing better front seats, and probably moving the old front seats to the rear (doubling the seating capacity).

 

[bobkart]

New front seats and motor controller installed.

I wanted a storage bin under the pilot seat too, but the vertical helm supports don't leave space to get your feet through when entering/exiting. I have a plan to eliminate those supports, but not right away.

The passenger seat swivels, and both seats fold down and lock when folded. The storage bin is lockable via padlock.

 

[GerryAZ]

Looks great! Enjoy!

 

[bobkart]

https://www.youtube.com/watch?v=rH6_SIkfqJ8

 

[bobkart]

I took this yesterday evening after installing the rear seats (which are just the front seats I replaced).

 

[bobkart]

Another testing session.

https://www.youtube.com/watch?v=ZvkUB6qncTg

 

[bobkart]

I'm selling last year's boat:

https://seattle.craigslist.org/est/boa/d/mill-creek-electric-hydrobike-prototype/7462996169.html

 

[bobkart]

Longest run yet on the new motor:

https://youtu.be/gKxEHpio7E4

 

[bobkart]

Longest run yet up the Sammamish River:

https://www.youtube.com/watch?v=ZLzW7iqZXoY

 

[bobkart]

https://www.youtube.com/watch?v=fmk1_ynLdwI

 

[jjeff]

Maybe I missed something, but I watched the whole video, but what keeps the battery box from sliding around?
Seems to be a real quality assembly, does the cover seal pretty well around the 48v prongs that protrude through it? if not my worry might be that in rain, water could get in the battery box and have no way to get out, due to the fact that the box looks quite watertight on the bottom.
Thanks for sharing! I bet those large 12v Li? batteries must cost a pretty penny, I know when I was looking for a much smaller to replace my 12v Leaf battery, even though those were well over $200 and yours looks to be several times that size and you need 4 to boot!

 

[bobkart]

Hi Jeff, the outer case is attached to the deck. There's a hole in the center of the bottom of the case, and I've installed rivet nuts at several locations on the deck, to allow different locations for the battery. A threaded-stud knob and an oversize washer allow tool-less installation and removal of the case to/from the deck. EDIT: there are also rubber pads on the corners of the bottom of the case, which help keep it from rotating (that and the weight of the battery cells).

I don't have the best seal around those power posts that protrude through the case list. We tend not to go out in the rain. If that changed, I'd consider some kind of hinged lid over that area that's open to the rear for the cables to exit. I also have some rubber grommets that might create a decent seal, but of course would need to increase the hole diameters in the case lid, and I'm not ready to move in that direction yet. For storage in the rain I have a box-shaped tarp that just fits over the case.

The four modules are each built from four 3.2V-nominal 200Ah LFP cells. Cost is not that bad when you get them straight from the manufacturer, but there is usually a multi-month shipping time going that route.

 

[jjeff]

Hi Jeff, the outer case is attached to the deck. There's a hole in the center of the bottom of the case, and I've installed rivet nuts at several locations on the deck, to allow different locations for the battery. A threaded-stud knob and an oversize washer allow tool-less installation and removal of the case to/from the deck. EDIT: there are also rubber pads on the corners of the bottom of the case, which help keep it from rotating (that and the weight of the battery cells).

I don't have the best seal around those power posts that protrude through the case list. We tend not to go out in the rain. If that changed, I'd consider some kind of hinged lid over that area that's open to the rear for the cables to exit. I also have some rubber grommets that might create a decent seal, but of course would need to increase the hole diameters in the case lid, and I'm not ready to move in that direction yet. For storage in the rain I have a box-shaped tarp that just fits over the case.

The four modules are each built from four 3.2V-nominal 200Ah LFP cells. Cost is not that bad when you get them straight from the manufacturer, but there is usually a multi-month shipping time going that route.

Sounds like it's secure, which I didn't doubt, it's just it wasn't obvious from the video so I thought I'd ask.
I wasn't thinking so much about boating in the rain but rather if the boat sat outside when not in use which it sounds like you have covered with your box shaped tarp, you also have any rain that could possibly get in the box covered with your hole in the bottom of the box, nice.
So is your battery box and batteries custom made by you or were they purchased off the shelf/shipped?
Thanks for posting your progress, always interesting to see your videos even if I'd probably never go down that route. A canoe is more my speed nowadays although back in the day I had motorized boats.

 

[bobkart]

So is your battery box and batteries custom made by you or were they purchased off the shelf/shipped?

I built the battery from individual 3.2V cells (purchased in 2020).

Thanks for following my progress!

 

[bobkart]

https://www.youtube.com/watch?v=2RcZpSUF_-E

 

[bobkart]

She finally got her name applied.

 

[bobkart]

Working on a second, smaller battery, for use as either backup battery (5.376kWh), or to add to the main battery for more range (156 minutes of full power). Could also be used by itself for short outings (~50 minutes of full power).

 

[bobkart]

https://www.youtube.com/watch?v=oU8O2HutjW4