Am I on the right track?

[WhiteH2O]

I've built one boat, but that was a 63" gas boat, so I don't know what I'm doing here. I'm trying to help my son build an electric boat out of a hull he found in my dad's garage. The hull is a shallow V, and is 18"x7.5". I would like a sanity check with what I plan to do. I'm a little afraid the motor and ESC I have will be too much for this little boat. I also have no idea what to do for battery power. I have old drone batteries laying around, but I don't know if it is 1000x too much, or not enough.

Here is a picture of the boat. I've put all the guts inside to get about a 30% balance point.

Bs Boat 01.jpg

I have a 2958 motor running 3380kv and a 70amp esc. I'm afraid this will overpower the boat and make it crazy unstable to run.

Here is an idea on how I think I could set it up. The motor this far fwd would get a pretty straight shot to the prop so I wouldn't have to bend the tube much.

Bs Boat 03.jpg

I have these trim tabs that look almost comically big. Put them on? I figure they would essentially make the hull longer and give additional stability.

Bs Boat 06.jpg

So, I'm sure you can tell by my questions that I don't know what I'm doing with electric and this hull. So is this motor/esc combo going to work well enough to continue the build? What batteries should I be looking at? Dual batteries to keep balance, I'm guessing? Trim tabs, yes or no? What props should I start with? Thanks to everyone willing to help me out with this build!

Just for fun, here is a quick video of the other boat I've built. https://imgur.com/gallery/dslM2a4

[larryrose11]

your getting there.
You will need a hatch cover that you can tape down, to make it water proof. A flas sheet will suffice.
I woukd not go over 3S on the batteries with a 3380kv motor in a mono.
1000 Mha is pretty small. somthing like 2000-4000 mha will be fine. More is just longer run time, but can be at the expense of handeling.
in your placment of the ESC, make sure you can get to the flexhaaft collet, because you will need to remove the flexhaft often for storrage and lube.
You can start with the 28-30 mm, 1.4 pitch plastic / graphite props to get a handel on how it runs they are cheep. 1/8 shaft should be fine.
I don't really run monos, so I can't comment on the trim tabs.

[NativePaul]

Yes, that power system is capable of way more than the hull will handle.

No worries though, it will only produce the power to drive the prop you put on it, so you can get it not to be too crazy with your prop selection.

What cell count is the battery? You could run 3s with a 27-30mm prop, but as the gear is a fair bit bigger and heavier than normal for a boat that size and I think it will suffer from a lot of prop slip, I would recommend 2s so you can spin a bigger 35mm prop for more efficient acceleration without being overpowered.



Try it without the trim tabs and see if you can tune it to run well, if not, fit the tabs

[WhiteH2O]

Thanks so much to both of you! I've learned I need to research and learn more about batteries for sure. I'll continue building this up, with the idea we may end up moving everything over to another hull depending on what this drives like. I'm sure I'll be back to ask more questions!

[WhiteH2O]

My son decided to continue building this hull, and we are just waiting on a drive shaft. We got everything mounted and put in according to all the input you guys gave. We decided to put the ESC on one side and a battery on the other instead of running two batteries with the ESC in the middle. Both are mounted on velcro to move the CG as needed. I got three props ranging from 27x38 to 32x45 to try out what will work best. Batteries from the drone are 3S 2200mah, but we can try other batteries if that doesn't seem to want to work. I think I made a mistake ordering drive gear when I first started ordering stuff about a year ago, as I couldn't find the a flex shaft that would work other than from Ali Express with shipping on the slow boat from China. Literally. If this turns out being a good combo at all, that will be quickly changed out with a new strut that doesn't take an odd size strut. Once the shaft arrives, it should only take an hour or less to get it all put together, and I will report back on the results!