Electric dinghy outboard
This was a controversial decision, against fellow cruisers advice. Almost everyone we asked said,; "Buy the biggest outboard your dinghy can carry, you will regret it if you don't". Still we opted to buy an ePropulsion Spirit 1.0 electrical outboard for the dinghy. Our thinking was that we would try it, and we could always buy a gas outboard anytime in the future.
There were some major reasons for our decision. We wanted to avoid having gas (petrol) onboard, which is a fire and explosion hazard. Gas needs to be stored and replenished regularly. Since we have plenty of renewable charging sources, it's possible to refuel at sea any time. So no need to find a fuel dock just for the dinghy. And since the Outbound carry 190 Gallons of Diesel, we do not fill up often at all. Getting dinghy fuel would be an annoyance.
Now after we've been using it since June 2018 almost daily (almost 5 years by now), we're very happy with our decision. We have two batteries to swap between, and get more than 5 hours of travel at 2 knots from each battery. If we "floor it", we can go 4 knots. But then only for 1 hour per battery. However, it is good to have that extra torque if the wind and waves are on the nose. We carry both batteries in the dinghy, so we just swap out whenever one gets empty.
Yes, we are often the slowest dinghy around. But we plan our anchoring so we don't have too long dinghy trips in front of us. If we had a gas outboard, we would have a much stronger one, since we then already had accepted the inconvenience with having gas onboard.
Each battery store 1276 Wh of energy. So doing the math, this translates into 106.3Ah (at 12 V). Assuming 12A charge current, this translates into 8.9 hours of charge time. This correspond nicely to our experience. However, we very seldom charge the batteries using 12 volt. Since we get 10 hours use-time out of the two batteries, we can normally go more than two weeks between charges. The likelihood that we have shore power at least once every two weeks is high. We always top up the batteries whilst on shore power.
We think a second battery is essential. We always have it in the dinghy, ready to swap as soon as the other one is empty.
There are several reasons for having two batteries:
Piece of mind. When leaving the mothership with a partly charged battery, it's nice to know we can swap to a fully charged one at any time. Preventing a nasty experience rowing upwind if the charge doesn't take us all the way back to the mothership.
If we only had one battery, we would probably always disconnect and charge the "one" battery, just in case... Having two prevents us from always having to do that.
If one battery is charging on the mothership, we can still use the dinghy with the second battery.
Other advantages with the electrical engine:
Starts by pushing a button.
Reverse-neutral-forward, by just twisting the handle.
Minimal risk to hurt anyone swimming when you do 2 knots.
Maintenance free. No carburetor to clean... And both batteries have held up well. No noticeable degradation of capacity.
Light, easily carried with one hand.