MikeAqua: I'm seriously interested in the idea of an electric boat project. Most of the electric boats in the US are flat water boats that operate at low speeds. There are water bodies in the US that don't allow hydrocarbon powered boats. There are excellent oil cooled stainless housing motors available and marinised battery packs. You can get electric outboards up to about 80HP.
There are a few substantial issues to be resolved for the fast planing hulls we typically use in NZ though: -
Battery weight - petrol/diesel (or an empty fuel tank) is lighter than the water it displaces. A battery is not. This reduces the ability of a boat to float when swamped - an important safety feature, which must be overcome with more buoyancy foam. this adds weight along with buoyancy.
Battery durability - will a battery withstand the pounding motion of a planing boat on a choppy day? A suspension system will add weight.
Recharging - a car will recharge when braking, no such option in a boat with current technology. A bigger battery per engine kW is therefore needed.
Electric field - will there be an inductive field from the motor/battery? If yes will this accelerate corrosion of metals especially aluminum?
Run flat risk - How predictable/measurable is battery drain?
There are some pros for an electric boat: -
- Quiet (good for fishing)
- Simple/reliable/low maintenance
- Could recharge with solar and maybe even deploy a wind-gen when at rest.
- Stable weight distribution. The battery will have a constant weight -unlike a fuel tank which lightens as fuel is burnt requiring trim adjustment.
- Low centre of gravity
Components for EVs and Boats
I've done research on EVs suppliers last year again - a lot of options with motors and control boards are made in US. Those same components are used in EVs and Electrical Boats.
For New Zealand Electrical Boats for recreation could be even more appealing than EVs.
Local search brings couple of companies in Auckland who seems to be onto it already - offering re-selling of components from overseas.
My thought would be to forgo the concept of a planing hull, and perhaps consider a catamaran design of some kind.
You've also made me think about the fact that there's 600kg of lead in the stub keel of my trailer yacht - and I really only need 7KW for short durations. Charging would be an issue though - even for that small HP.