In a message dated 8/22/2008 11:46:06 A.M. Central Daylight Time,
ShellyDalg@aol.com writes:
Hi Dean. Probably a good choice given the high cost of the new batteries,
and the speed at which the technology changes. What type of charging operation
will you be using for the 72 volt banks?
Like you have to cross that bridge pretty soon. I do not have a clue at
this point. All of the
sparky stuff I have a friend doing all of that, but I now it will be some
work
I'll be using 3 banks of three at
36 volts, and plan on charging them in the sub, but I haven't reached that
point yet, so haven't spent any time investigating chargers. I'm pretty sure
it takes a 240 volt charger to pump those things up. I wonder if that will be
a problem finding a suitable power source at the average marina.
Have you gotten your main propeller yet?
That is still up in the air also. I really want to go large diameter and
slow. But I may end up
going with smaller and faster. Like you, a later plan, and do some
fine tuning. Some sort
of kort nozzel for sure. I will just have to handle the cavitation for a
while. I am vectoring the main propulsion not sure how far yet but should
give me
a lot of manuverability.
I was thinking the "weedless
wedge" props that come with the Minnkotas could be improved on. I have prop
rings on the two rear thrusters and was considering up-grading to multi blade
props after sea trials are done. The two side thrusters will have exposed
props so I''ll retain the stock props on those in case I get into some
kelp ( For sure will be trying to cut through some kelp )
It may be I'll need rings on those too, so I don't
whack a whale or something with the props. They can easily be added later. In
reading about Kort nozzles, I know the power is greatly improved with them,
and in fact, Just a simple ring adds quite a bit. If I can't find reasonably
priced multi blade props that fit the Minnkotas, then I'll probably take a
swing at making my own from cast aluminum or maybe fiberglasss.
I'd really like to have brass ones though. Got some time before I need to
switch them out, so that decision can be stalled for a while.
In talking with Vance and the other experienced guys,
a slower moving but larger diameter prop gives better speed. I assume you have
your main motor geared down. What is the prop rotation speed?
There's a whole science behind prop design and I'll need to educate
myself on this a little more before I commit to new props. Well, better get
back to work. That thing ain't gonna build it self! Frank
D.