Hi guys - Im new to this forum - but i have been building and testing etow myself for a couple of years now… my build is getting closer to a commercial unit all the time - I do heaps of foiking and use ny builds as foil coaching tools for newbies wanting to learn to foil for a job now… we build Biaxial carbon foil boards too - proper foil brain issues 
i am yet to conquer steering from the remote… probably my final hurdle …talking to BreMote dudes now…
Hey Mark,
I am also based in Vic, planning a tow build. I am not sure if you are building or sourcing your batteries, but would you be interested in selling a standalone battery back?
yeah mate sure - im releasing all our our etows as DIY component kits…
batteries / props / hull / pro guard and motor mounts are all designed to be interchangable depending on your foiling or wake affliction …
Weve gone and spent a lot of tine of batteries designed for etow - they have to be able to handle big outputs for a long time - one for up to 6000w motors (1 -1/2hour full noise) - So were using the expensive samsung s50 cells - and the case is a china import made to fit 14s6p… be doubled (2 batteries) to run up to 12,000 w (twin 6000w ) for wake tow or surfboards… or just to double the foiling range to 3 hours plus…
Ive got the first shipment due here in a month…
pricing to be finalised but around $1k gst inc per battery is what were aiming at…
the case and ports are ip67 with sb 50 anderson connection used for charging as well as output… it has insulating waterresistant rubber boot as per our shitty post production pics attached below…
excuse my spelling im all thimbs.
hahah… you’ll find me on the phone via my website - hsfoil.com - the components lists on etow is actually really massive…
That sounds awesome. Keen to see what other components you have available before I start ordering parts. I am pretty comfortable with 3D modelling/printing and composites so keen to build my own hull eventually and motor pods etc, but my electronics experience is very limited and building a large battery pack is beyond my comfort level currently.
I assume you are aiming for steering via a rudder, as that photo looks like it has two fixed inline motor pods?
yeah ive got two variations built and operational - one is single 6000w motor and about to have rudder steering…
The other is the ‘aligned’ twin motor version - shown in the picture…
the ‘inline motor version’ there is amazing though headwind chop - and has great take off torque - it runs twin 3000w motors - and opposing props…
i could add servo rudder steering to it - I did test rudders at full 45degree left and right to see how it went
The issue of course with twin ‘aligned’ props was that rudder steering starts to get pretty ineffective - its got like a 25- 50m turning circle!!!-
very happy with that model for a good year or so its been u real - I see it now as the stepping stone that really nailed the hull shape design that handles 20kmp+ into heavy chop…
the twin props really ‘pull’ the hull through chop with one prop semmingly always in the water as chop is crested you dont get the power surging issues or the jumping around ive experienced with other etow ive tried…
I love it on foil - its lack of steering has never really been something i needed personally - Until i started surfing Sanur in bali and saw that without the steering id have had like 2km paddles back…
The differential motor ateering on side by side prop set ups look to be capable of really sharp turning if required - u real for picking up students while coaching and facing them in the right direction at low speed…so thats my next build …
imnsure it will have its issues too - but Ive got through most of the big hurdles on the first 5 operational etow… im up to like version 48 now
everyone that sees my etow goes like " thats amazing" man thats the best - how do you steer it?" and im trying to explain that if you pull out left on the rope - it turns right - its really simole and intuative - but seriously no-one gets it… Im iver explaining. its a feature that people want on etow even if ultimatly once they are learning more they will use less and less…
Looks great man. Do you have any insights on rudder steering? Im looking to add one to my diy tow boogie but concerned that the waterproof RC servos are too small?
My Question also… I was hoping some other builders had good solutions for Rudder servo’s !!!
Anyone know of one?
Thee BRemote V2 reciever has the ports for servo control built in…
I tried a rudder initially, I got the biggest servo I could find and then geared it down with some printed gears. Use a RC remote in one hand and the flipsky in the other.
Quickly found the rudder wasn’t the solution, it either had to be huge, or quite far back to get enough purchase to turn the Boogie.
Another thing I found that unless the rudder was in the flow behind the prop it didn’t turn the boogie until there was forward movement.
Also seemed way too fragile - if the rope was caught and you and you pulled the throttle it would be bye bye rudder. Maybe ok for a DIY version, but not to sell.
It looks like it does nicely in the chop, would love to see you push it to the limit conditions wise and share a video, looks promising
Pushing hard through chop is the main shortcoming I have, and am working on some ideas to improve (foils, cat, wave piercing etc)
That’s the biggest limitation, the others are easy enough to work around. But if you turn the motor or use 2 motors you will end up with options for stationary turning.
Great words lads ! We’ll all get there Im sure… Thankyou for the feedback and experience strongarm re the rudder - I expected as much and you’ve saved me a lot of time. Its firmed up the differential Twin side by side motors solution.
There is some more video of the ‘Tow Bogan’ in chop here on youtube here
https://youtu.be/nzSPHpzYOo0
If only I’d looked at that shape first it would have saved a lot of tests…Looks great, thanks for sharing!
Because you are down the offshore boat rabbit hole, I wondered if you considered surface piercing props? lots of interesting benefits, and drawbacks. Most of all I would hope it would handle re-engaging the props better after ramping a wave
Surface Piercing props ! Now they would be perfect. Where do you get such a thing and are they available in Mirrored rotation?
Ok - Couple more pictures of the Tow Bogan build… Lot of work on ‘Self righting’ after a bunch of great surf sessions on the v1, its time to build a mould and get it to roll back over after clean up sets. These Pics are the 'Plug - Im going for a full solid hollow Fibreglass hull with pre inserted 316 stainless bolt up mounts, Draining or ballast bung - Sealed independent battery cavity - the lot. Something you can adapt to the various motors and motor mounts out there.
If you are making a mould, count me in for one 
Shipping to UK?
Some ideas:
For a surface piercing, I think there is probably a lot of experimentation to get it anywhere, possibly running oversized props for more bite, as I think they main issue with them will be lack of low end
Here is my sketch for boogie that I plan to try.
Wave piercing: I think this is possibly a good direction. If it goes through waves, you have less cavitation to worry about!
Self righting: I wonder if you might try a flood chamber, will cause it to self-right more quickly, and you can simplify the design / make it sleeker to punch through waves
Surface piercing props are notoriously bad for tow boats as they lose the extra bite from the prop. They excellent for racing boats though.
The issue with this is the resistance will force you to stall the foil. The size of the tow setup means its far to light to pierce through a wave or chop while towing.
I think both of those issues are likely overcome initially by rider skill initially and tinkering eventually.
I use only 60% of throttle on single 6384 12S on a prone board to get going, and with dual motors I could imagine doing away with the bite, key is minimal drag when you first hit the throttle. If you treat it like a tug boat off the mark then yes the surface props will certainly not work.
In the below video from Mark, there are a few instances where it pushes through the wave, where a boogie would ramp. I think this direction of deep Vee hull is very sensible, and I think many other offshore racing features are relevant
