DIY Electric Outboard

All this time in lockdown has me scheming up new ideas, and I keep finding myself coming back to one – the electric outboard.

We absolutely loved our experience cruising and the South Pacific on renewable energy.  It’s clearly the best option for the frugal sailor on a limited budget.

In the interest of continued improvement, I have been reflecting back  on our experience and trying to identify areas that could use improvement.

The Sailor’s “Car”

dinghies

The dinghy is vital to all cruising sailors. It’s how you get to and from shore to get supplies. It’s also how you get out and explore the areas around you, areas where the mothership just can’t go.

When we were gearing up for our voyage, we were looking for a good sailing/rowing dinghy that kept to our renewable energy, low carbon footprint mantra. Tinkerbelle was our solution.

Tink is an old Tinker Tramp, an inflatable sailing dinghy that was made in the UK. Tink rolls up and stows on deck and came with an optional life raft kit, she is perfect for a small voyaging yacht like ours.

Tinker Tramp Sailing

Unfortunately, Tinker is no longer in business, but there are many small roll up or take-apart dinghies available on the market. As with all dinghies, they don’t move themselves! If you want to check out that beach two miles away, you have to get there somehow.

Being broke, young, and full of vigor, our solution has mainly been a set of oars. Over the last three years I came to find myself enjoying the art of rowing. My back stayed strong, and oarlocks can be found or jury rigged pretty much anywhere.

The downside?

Just try to convince yourself to row for miles when you are already standing on a perfectly beautiful beach.

Our limited range kept us from snorkeling passes and exploring those farther off places, unless we joined friends who had a dinghy with a powerful outboard.

THERE HAS TO BE A BETTER WAY

Enter the Electric Outboard

Torqeedo Travel 1103 C Outboard Motor w/ FREE Travel Bag Set – Wee ...

We have seen a few small Torqeedo outboards during our travels, but none of the cruisers we met were in love with them. They are light, maintenance free, and packable, what’s not to love?

THEY WON’T GET YOUR DINGHY ON A PLANE!

Simple as that.

We want to go fast! Forget that we don’t have to row. Forget that there is no maintenance. Forget that you never have to carry gasoline. Forget that you never have trouble starting it. It’s hard to brag about all of these positives when you are wallowing in the wake of the neighbor’s dinghy that ripped right past you.

What’s on the Market?

There are companies offering more powerful products. Elco, Torqeedo and ePropulsion all have offerings that can get a tender on a plane. They appear to be quality, well designed systems, but I haven’t actually seen any of them around. Unfortunately, they are all outside of our budget.

On the cheap end, you can find offerings from Aliexpress, Karvin, and Golden Motor. But based on their websites, I can’t reason sending them upwards of a thousand of dollars with my fingers crossed.

If anyone is willing to donate one of the above to us, we will happily test it and do a full review

Project Outline

Build an electric outboard for small, folding inflatable dinghies. Ideally, the outboard will fit Tinkerbelle and get her planeing for an hour or more on a single battery charge. As with Cinderella’s Manta Drive, it must be affordable to the budget sailor and robust enough to handle cruising in remote locations. I also want to build my own LiFePO4 battery bank that will supply power to the motor. The system must charge easily from our current solar panels and I’d like to test the feasibility of using the outboard as a hydro generator.

Goals

  • Power – enough to drive a small inflatable on a plane for over and hour
  • Reliability – use robust components to mitigate failure
  • Affordability – cost less than a new gasoline outboard
  • Ease of Charge – must be easy to easily charged from Cinderella’s current system
  • Hydrogeneration – determine feasibility as a yacht hydro generator.

Parts List/Cost Breakdown

Outboard
Donor outboard engine $0
Montenergy ME1716 Motor $600
Roboteq Motor Controller $345
Contactor $50
Breaker $50
Throttle $50
Fuse Holder $20
Safety Kill Switch $35
48V – 5V DC-DC converter $16
Misc wires/connectors $50
Total $1,216
Battery
Roboteq BMS $495
Breaker $50
60Ah LiFePO4 cells $880
Misc wires/connectors $50
Case $100
Total $1,575
Outboard and Battery $2,791

I’m hoping we can see the performance similar to that of a conventional 5 HP outboard. A brand new Tohatsu 5 HP retails at around $1800. While our project will cost about twice that, I’m hoping that we see the ROI in the form of free fuel (from the sun) and lack of maintenance.

Donate

As with the Manta Drive, we will share our experience while making the plans free and open source. If you want to help speed the project along, please consider donating to our cause!

2 Replies to “DIY Electric Outboard”

  1. Ley me know what lifepo4 you end up choosing i am looking at buying some too. I like the idea of an hydrogenerator turning i to a dinghy engine. But does it have to be outboard ? since it is light it could be mounted higher than the free board and yet be in board. Maybe be you can get inspiration from thai speed boats. Checkout pics online if you have’nt seen them before your eyes. Regarding making a sailing dinghy plane i seriously doubt that the hull design will help you but there is no harm in trying. I would ask sponsorship or copy the design of “offshore tenders” (made in NZ) which plane with little power. Keep the creativity going !

    1. I may have a line on cheap LiFePO4 cells here in NZ, I will keep you posted as the project continues. OC Tenders actually offered us shop space for the build and a dinghy to test on! Let’s see what shipping to NZ looks like.

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