Computer Engineering Team Build @ Santa Clara University

I could leave the connectors entirely exposed and have no issues in fresh or saltwater. The resistance of the magnet wire will be less than that of the path through the water. The heat shrink I use is adhesive lined for waterproof seal. I appreciate your concern and will use a wrap of electrical tape prior to adhesive lined heat shrink.

Best,
Peter

If you don’t believe me you can prove it for yourself. Use a DMM and put the probes into a saline solution (matched to that of your venue) at the separation of the connectors in the mast clamp and measure the resistance. Compare number of ohms to the resistance between two phase wires of the motor. Electricity will take the path of least resistance.

OR

Watch this video

I don’t think he is clear in explaining why it’s okay for the connectors to be exposed to the water (he says something about it being pulses which is partially true). If the connectors had a constant potential difference and current flowing electrolysis (bubbles on connectors forming due to splitting hydrogen and oxygen) might occur and quickly corrode the connectors. I believe the pulsed nature of this signal does not allow for time for significant electrolysis to occur in combination with a less resistant path present (through motor magnet wire). I gave this a good deal of thought because I was really worried about being electrocuted.

Best,
Peter

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The oblique mast cut makes cabling, waterproofing and pod fitting easier:

]200515 Oblique mast cut_

We have discussed this safety issue on other treads already.

If you can waterproof them just do it. For your own safety. Current won’t forgive you that easily

Understood. I will and post pictures.

Best,
Peter

As previously mentioned we are switching to the 2020 Slingshot Outwit 7’6" board due to damage to the Airstrike.

I used the footstrap holes to mount a ratchet strap for securing the VESC enclosure. It is not a perfect solution but with first test on Monday it will be fine.

I mounted both boxes with these ratchet straps and they are not up to the job. It is nice to know how it will all look but I need to replace the straps with ones that have a proper ratchet (as opposed to weak spring loaded clamp). The boxes have ~2" of play and don’t seem like they will fall out but better not risk it.

It’s coming together nicely Peter! Looking forward to the test on Monday. I am a bit worried that the boxes are where you will need to have your feet. You stand more forward than you think because of the bottom mast push. Only when you are on a wave and reduce motor push (or folding prop) you step a little back to the usual surf foil stance. I think your back foot will be somewhere above the wing, so slightly in front of the mast. The front foot is probably where the battery box is.

Go figure that using the foot strap mounts to mount the boxes is right where your feet need to go! I have velcro on the bottom of the battery box as the original plan was to stick it on the front of the board in front of the foot pad. I was advised this was too far forward. What do you think?

Top view with foil on top of board. Do you generally stand directly on top of the front wing?

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Better to keep the area above the front wing free
Depending a board length … your rear feet will find it’s place from the front of the mast to the front of the wing

The COG has nothing to do with the mast.
It is always the main wing which determines the COG. Generally you want your back foot above the main COG point so that you can then just shift the front foot easily to control the rest.
If your back foot is positioned correctly you should just about be able to foil on one leg…

Thank you!! Would you move the battery box forward or backward to clear this space?

Are you suggesting move both boxes to the back? I appreciate all the input as I have no knowledge in this domain.

how are you going to get started off, Most people will lie on the board on the belly.

Best is to try and I would eventually anticipated to put the battery box a bit more in front , just so you can adjust it easily on the first try

Like a mount plate ( secure on board) with straps for battery case

My first build I put the battery completely in front to have more room
But the best place for riding in between for feet

I have the batteries in the board but positioned between my feet. It makes sense to have the weight distributed like that.

I’m thinking of stacking both boxes on the back. Can someone who has been on a foil please chime in here? I am going to button up the electrical system but really need guidance here.

Best,
Peter

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More forward so it’s between your legs. Stacking is fine, keep it simple. Having no box in back is better for prone start. Your belly will be on the box, you need lots of weight in front as you get started. But board looks like it has lots of volume so maybe a standing start will work. Only downside is that the ESC box will have less water contact for cooling down in between foiling. But I would not worry too much about temp yet, you have piece of mind with the VESC temp control, it will just slow down and eventually stop if too hot.