Originally Posted by newhaul
Ok guys I know this seems really weird from me but is a 6hp 48 volt motor enough for my 9k columbia
29 defender long keel
? May be able to get motor and speed controls for real cheap
So the Defender weighs slightly less than a Cal
34 but also has a shorter waterline.
The following is estimated performance of a Cal-34 in calm conditions using a 48v system.
Kts Amps Watts nm Range (300Ahr-80%DoD)
2.5 10 480 63
3.2 20 960 39
4.0 40 1920 23
4.6 60 2880 18
5.0 80 3840 14
5.4 100 4800 12
5.7 120 5760 11
Is this a 6hp motor which would be 4476W or a 6kW motor which would be 8hp?
Motor, controller and 300Ahr of batteries
is about what will fit in the space that an A4 and it's fuel tank
If you go all in on solar panels
you can probably go 2.5kt all day and end up with more energy in your battery
than you started with.
A 4500W motor will be good for getting you in and out of the marina and harbor, it will let you set and retrieve your anchor
, it will get you out of the way of large ships that are thinking about running you down and it will help you thru tacks in very high winds. It's not going to get you long distances at speed, but you will able to slowly motor straight into wind
and waves for short periods, 60-120min. With the electric motor
you would have power almost instantly available.
The original Columbia-29 had space behind the rudder
for a small outboard
in a well. Atomvoyages has videos on how to convert a lazarette to a motor well with the ability to tilt the motor up for minima drag sailing. Whether your Defender has sufficient clearance behind the rudder
for this to work
would require some investigation.
A 6hp Tohatsu high thrust motor will push an Alberg-30 at 5.5kt in calm conditions.
There is no reason you couldn't run the electric motor
and the outboard
at the same time it you needed shortish period of very high thrust.
If you go the electric route
with the outboard, you will probably find the outboard mpg is about the same as a diesel
despite the outboard being gas/petrol. The reason for this is that while the diesel
is more efficient at max power than an outboard at max power, you probably run it at 1/2 power or less most of the time and efficiency falls way off. Whereas with the outboard you will probably run it at 80% or more power to get the 5.0-5.5kt cruising speed you are used to and fuel
efficiency will be near max and similar to the diesel, perhaps even slightly better.
If your diesel still runs fine, it probably isn't worth swapping out unless you are really invested in the idea of going EP.