About a year ago I traded an aging 1983 Fleetwood Southwind 30ft Motorhome for my first boat. The boat was a 1981 Cuddy Nautique with (what I thought was) a minor knock in the engine but a boat in otherwise great condition. I viewed this as pretty much getting a boat for free as the motorhome we traded was one we previously bought for $6400 and lived in full time for 6 months. The savings from living in that motorhome while in LA amounted to more than the price we paid.
Anyway - that minor knock turned out to not be so minor and after only a few trips out in our new boat the motor blew and left us stranded near island white just off the shore of Long Beach. We were towed back and began planning for our next steps. We knew a new motor was inevitable at some point but we had hoped to get at least one season before taking on that expense.
I started looking for motors, costs to replace, etc and it quickly became clear that this was going to be an expensive proposition (at least $5k). I personally am not a fan of internal combustion engines (we own two teslas and an electric motorcycle - the boat and RV before it were our only ICE vehicles) and I really wanted to have an electric boat. After some searching, I found Electric Yachts - a company that specializes in repowering boats (usually sailboats) with electric propulsion.
I determined that for the same cost of an engine replacement I could install an electric motor and several deep cycle golf cart batteries. I worked with Mike at Electric Yacht and purchased the QT10 sport. I was able to install the motor myself using only basic hand tools (I had someone from craigslist remove the old motor for free in exchange for the core). The old engine weighed over 1000lbs and the 100gal gas tank added another 600lbs when full but the new electric motor only weighed 50lbs. This gave me plenty of available weight for lots of batteries.
Now I have a fully electric Cuddy Nautique capable of speeds up to 7knts and with a cruising range of up to 40nm. I call it the Cuddy Electrique!