Originally Posted by sv Shearwater
They use hydro because it is most efficient. They can generate 40 amps at 12 knots or so and considering these boats will average 13-14 for the entire circle that is a big bang for the buck. keeping in mind the weight savings due to less fuel
they need now.
All of the boats have at last two generation sources. Some have all four (diesel, wind, solar, and hydro). One boat, Acciona, does not have a diesel
engine, so all generation is from, water
, wind, and solar. If he makes it, he will be the first sailboat to circumnavigate non-stop without an engine.
Clearly they are not perfect though.
Someone mentioned regeneration from the electric motor
. What are max amps you can get that way, and at what speed? I'm seriously I interested in both the electric motor
and the hydrogen, but maybe it isn't necessary to have both.
The cruising version will generate 40 amps at 8 knots or so. I could stand for that kind of generating power.
From all the failures and damage it seems to me the race
is also the shakedown cruise
I did not realize this was a nonstop race
all the more reason why I would want backups or at least some spare parts
for the primary energy systems like the Hydro.
I'm sold on electric propulsion
for my boat having just past the five year mark of having it installed. The amount of regen depends on a number of factors keel
and prop location size, pitch
etc... On my boat the system is primarily used for auxiliary propulsion
. Regen is just a bonus if the conditions are right. For the first few years it was allusive thing to make happen. Then one day without even trying there it was:
THE BIANKA LOG BLOG: ANOTHER ADVANTAGE OF ELECTRIC PROPULSION: REGEN
I can start getting the motor to regen at around 6 knots. It is minimal but, it is positive flow into the battery
bank if you are sailing several hours it will add up. It also increases rapidly with boat speed. I also seem to notice wave action can pulse it up too. This summer I did see 100 plus watts on occasion. I'm still using the same 3 bladed prop I had when I had the diesel. So I might be able to improve on that if I want to spend the $ for a new prop optimized for electric propulsion and regen. My boat will also never be moving along at 19 knots either or even 12 (unless surfing down a wave).
Personally I don't see the need for a hydro on my boat since I already have the regen availiable, solar, wind and Honda
. I'm also not doing any extended round the world racing
but, my experience with electric propulsion has been all positive. One nice thing I've found with EP is I start off having the prop turn just enough to negate the prop drag which is nice in light winds as the wind picks up the amps drop and eventually things move into regen mode. Saw 3 amps at 48 volts on one afternoon which was sweet.
Of course it's just a drop in the bucket compared to what the Vendee guys are seeing with their Hydro units at 12 knots but, I was happy.