YAHEF from Norway

[YAHEF]

Time flies. More than a month since last update. This turned out to be kind of a slow build but I’m in no hurry since the winter is starting to get a grip of Oslo. No efoiling for me until spring.

First of all I’m happy to see that others found the way of creating the mast clamp useful and even developed the concept. Thank you guys for that.

The last month I’ve made some progress on the remote control. The remote will be quite similar to @samisin excellent approach, but I’ve chosen not to all the electronics into the remote, only basic things like the hall sensor, display, bluetoooth communication, IMU and CPU. GPS and SD-card will be inside the electronics box and the data communicated to the remote.

But the main thing this last month is the the frame for the box to fill the hole in the inflatable.

https://a360.co/2q237xW

The frame is basically created from a profile sketch and the option Create->Sweep in Fusion 360, kind of the same way as the mast clamp. Also added holes for threaded inserts to fasten the aluminum bottom and some support on the top.

I have used the same concept as for the mast clamp. 3D-printed the frame in 6 parts with 5mm overlap to join the parts and with low infill. It’s a monster printout, almost 3 times 24 hours. Some extra manual work with cutting the side walls open, for the resin to float seamlessly between the printed parts, making the frame almost homogen. The parts are first glued together with Tec7 for the resin not to escape.

When the 5mm aluminum bottom is be screwed and glued to the frame the strength will be really solid, no need for extra reinforcement. The only drawback I can see is that the entire box with both bottom and lid will becomes quite heavy, around 6 kg. If or when I do this again, I will make the profile a bit thinner to save some weight. I believe it will be solid enough if I cut the profile with 1cm

Also, the 100mm stainless screws has arrived so in the next couple of weeks I will be able mount the bottom to the frame, the motor to the mast, the mast to the box and have a testrun in the bathtub.

[samisin]

Liked the display! What is the part number for the dpsplay?

[YAHEF]

It’s a regular ILI9341 2.2 inch from aliexpress

Like this one
aliexpress.com

[samisin]

Seems very bright display. I am using st7735 1.8 inch. Even 1.8 inch was challenging to fit. Good job on fitting the display there

[nice2cu]

It looks realy professional!!!
You filled in polyester, how and where you do it?
Why you dont print it with 0% infill?

[YAHEF]

The trick is to peel off the white frame around the display, leaving you with only the display itself. Then there is the acrylic glass, painted a black frame making only the pixels visible. The two parts then goes into the modifyed @Hiorth lid.
Then I have a question for you. How did you make your navigation buttons?

https://a360.co/2Wl4gNd

[YAHEF]

Thanx Robert. Yes I filled the frame with polyester in my garage pouring it in little by little and yes, it smells like hell. Make sure to use a mask. The alternative is to use epoxy, which doesn’t smell that much but costs 3 times as much.
The parts are printed with 8% line infill

[samisin]

I designed a pcb that gets screwed to the lid. To waterproof it, another rubber cover sits on top

[Onhill]

Nice work yahef i have to try it

[YAHEF]

I have an inflatable hydrofoil!!! Still miss the e prefix but I’m getting there

[sat_be]

What is the thickness of the aluminum bottom plate? I’m on the same route and planned to use 4mm. How do you fix and seal the mast to the box? Picture from the inside would be interresting.

[YAHEF]

Hi Daniel. Well, it’s not very exiting inside the box just yet. It’s quite empty but the next thing will be to get the wires and the water hose inside the box. I’m not sure yet how to seal everything. I want it to be easy to take the mast on and off, so we’ll see. I will post my findings as soon as have something.
I’m using a 5mm aluminium plate but I’m sure your 4mm will be enough. I just wanted to be on the safe side.

[YAHEF]

I see that elevate.rocks takes another approach. Their box seams to only have the bottom and top plates touching the inflatable. That is definitely another way to go. Upside, less weight, easier to print. Downside smaller box, but obviously big enough.

[SoEFoil]

There are two clever parts in this Elevate design:

• two-skin connection: the mast plate is linked to both top and bottom surfaces of the box through tubes or box walls (like Tuttle boxes are supposed to be installed).
• the box walls create a double I beam
  Its better for the box stiffness, therefore for the waterproofness.

It wouldn’t be the case if the four mast plate screws were fixed to only one surface (even 5 mm) right below the inside of the box.

[YAHEF]

@SoEFoil, you are right, good spotted! I will seriously consider to alter my design slightly. Either by adding 4 aluminium cylinders, connecting the bottom to the top or move the plate slightly back, making it possible for the rear screws to run through the solid wall and the two front ones connected to the top with aluminium cylinders.
The third option is of course to start from scratch and have a go on elevate.rocks proven design

Edit
The third clever part with the Elevate design is that the wires doesn’t have to go directly into the box from the the plate. They can enter the box with real through hole connectors from the side, making it easier to waterproof.

[SoEFoil]

The third clever part with the Elevate design is that the wires doesn’t have to go directly into the box from the the plate. They can enter the box with real through hole connectors from the side, making it easier to waterproof.

So true. The 2 aluminium cylinders are threaded to receive the mast base plate screws plus offer enough empty space to allow hand connections between mast and ESC connectors. In this external non waterproof area, you have plenty of space so that you can use cable glands plus @Gobbla’s XT90 fast and waterproof connectors + CPC water quick disconnect.

[tylerclark]

Do you have the 3D files for this custom inner core board design? I have 2 inflatable “cores” or whatever and I’d like to look at different options where I can more easily take batteries in out, seal electronics, etc.

[SoEFoil]

Would you post picts of your current box setup ? How does the mast connect to the box content ?

[YAHEF]

If you scroll up a bit, you’ll find it. YAHEF Post 8

Fusion. Up in the right corner it say’s download

[YAHEF]

A week of much back and forth, what should I do? Stay with my original design or have a go with the Elevate design.
Well I found a fourth and a fifth advantage with Elevates design. It’s much easier to slide the inflatable on to the box and I think I will save almost 2 kg.

So with these five advantages, the decision was easy. I need to change my design. The drawback though is less space for battery and electronics but I think I can live with that.

• Two-skin connection to the plate box
• Double I beam
• Wire waterproofing
• Easier to slide the inflatable on
• Less weight.

This time I decided to to a mock first, so after a couple of hours in Fusion 360 to get the dimensions right, it was off to the hardware store and by some plywood. Hand here is the result.

It sits quite nice to the board but I discovered that the back of the inflatable is a few mm thinner than the front, so that’s something I have to compensate for.

Since I’m no way near ready I will not share any 3D files just yet but here is an image of the concept.

Another thing I’ve been trying out this last week is the top plate, or at least the concept of it. This includes something I’ve never done before. Fiberglassing.
After a few test I ended up with 3D printing the inverted copy of a plate, like a mould, with small elevations indicating where holes should be drilled. Coating the inside with some release fluid and on to filling the mould with epoxy and pieces of fiberglass.
After 24 hours of curing, the plate popped out really easy. With a bit of sanding and perhaps a thin coat of epoxy to cover the structure you get from a 3D printed part you have a strong plate with exact measurements.