John Cornicelli wrote:

We are halfway through an electric conversion also, ..

Wind turbine on top of the foremast, best place for it!

avid Thatcher wrote:

If there is no wind and I have to motor all day I have gotten about 30 nautical miles out of a 12 litre tank of fuel motoring at a bit over 4 knots.

David, I have never pretended to mathematical competence, but my simple mind says that 30 divided by 12 equals 2.5 knots.  What have I missed?

Du reste  I agree with everything you say.  If my Bukh 10 were to die, the only thing that would stop me going for the outboard option is the plethora of perfectly good Bukh 10s that have been ditched by owners who wanted more power.

Fuel consumption depends a lot on how clean the hull is and wind and sea conditions. But I have been surprised how long a 12 litre tank of petrol goes for. If there is no wind and I have to motor all day I have gotten about 30 nautical miles out of a 12 litre tank of fuel motoring at a bit over 4 knots. I think the main disadvantage of petrol over diesel might be fuel range on a long ocean passage if you need to do a lot of motoring. When we do an extended coastal cruise of a week or more I carry 2 of the 12 litre Yamaha tote tanks and a 20 litre jerry can. I have always had a surplus of fuel.

I suspect that the Badger style boat might be a bit more easily driven than Footprints because you do not have the extended topsides for the fill length of the boat. I am about to do a 100 mile passage to the Bay of Islands later this week so will take a careful note of how much fuel I use, although hopefully I will be doing a lot of sailing.

What are the downsides of an outboard for an auxillary motor? 1/ Possible lack of fuel range compared with a diesel but that depends on the size of motor. 2/ combustability and explosion potential of the fuel although on Footprints the fuel sits in the outboard well compartment and is self draining. 3/ Possible cavitation in rough sea conditions if the motor is too far aft. 4/ Lack of battery charging capability compared to a diesel but then you can tailor your electrical consumption and fit out to that, and fit more solar panels. 5/ Possible drag while sailing caused by the open aperture of the outboard well. On Footprints I have found it best to have a flap closing off the well when the boat is sailing.

What are the advantages of an outboard? 1/ Significantly lower purchase and installation cost but you need to factor in the construction of the outboard well. 2/Light weight, the Yamaha 9.9hp high thrust motor weighs only 50kg. 3/Ease, and lack of required maintenance. 4/ No motor, fuel tankage to take up interior space and no smell of diesel in the interior of the boat. 3/ 3 x less hull piercings - shaft, exhaust, and cooling water intake. 4/ Usually significantly quieter in operation than a diesel motor. 5/ Easier and lower cost upgrade/replacement in future should that be required.

I think that another point worth noting, and I do not work for Yamaha, is the Yamaha high thrust 4 stroke outboards are the only outboards that can provide a true diesel replacement option for a displacement vessel. None of the other outboard manufacturers offer a motor which has the low ratio gearbox combined with a high thrust propellor. Also on Footprints the motor has remotes and electric start so once I have used the winch to raise or lower the motor the operation is the same as for a diesel motor.

Hello Kurt

Congratulation for your DIY electric propulsion sytem.

On my Tiki46 catamaran with Hybrid Marine I put a parallel propulsion system in each hull : a diesel Beta25 which is coupled just after the gear box with a 10KW 48Velectric motor and one battery bank of 10kwh in each hull and 4 solar panels of 240W.
This afternoon we have had a short sailing test (with not enough wind) and I enjoyed to go away from the marina and to come back only with the electric motors (and it's easier to maneuver than to use the 2 diesels).
The Tiki46 Apatiki of our Belgium friends has a serial electric system with and electric pod under each hull and a diesel generator + battery banks .
Now the choice of different propulsion electric systems increase year after year, more and more sail boats will have a series or parallel propulsion system.

Bertrand

Kurt Jon Ulmer wrote:

For the next year, we'll be here in NZ and in the trade~blessed Pacific Islands. Then hopefully on our way to distant problematical spots. Until we get there, I think we're fine. But with compromises.

Indeed. Making choices for where you are now with an eye for making where you will go later possible is my speed!

For example, I've got plans for a good heating system on Flutterby. And I am making do with a portable propane heater and electric space heaters until I go someplace cold enough to need it.