T-Pain Is On A Boat: Re: [Electric Boats] Thunderstruck versus... well everyone else!

Sunday, August 11, 2013

Re: [Electric Boats] Thunderstruck versus... well everyone else!

Look carefully, I think you'll find that thunderstruck use the ME-0913 motor in their sailboat kits.

About gear reduction, you'll be darn lucky if 2.0:1 is the right ratio for your boat and prop. I thought long and hard and decided on 2.2:1. Boy was I way off, I'm now at 3.0:1. Eric has written a lot about ratio in this forum.

Chris

Sent from my iPhone

On Aug 9, 2013, at 22:01, Jeff LaCoursiere <jeff@jeff.net> wrote:

Hi Bob,

I did run across cloudelectric today and discovered the parts that make up the thunderstruck kits. And was frankly amazed. The ME907, which is likely underpowered for my boat (get to that in a minute), is only $399?! It does seem that if I consider myself handy, at least with some help from the yard, I can go a long ways with cloudelectric. Exciting.

So I do have some questions. In some of my research I was supplied with a power/speed worksheet based on the given info of LWL, tonnage, etc. I was surprised to find that at the speed I normally motored with my Yanmar 30HP engine (6kts) I only needed 120A @ 48v, or around 6KW. My hull speed is somewhere just over 8kts, but I never pushed my diesel that hard. Maybe I should have! Its dead now. Kind of forces all this research.

So if I were *happy* to take a top motor speed of 5-6kts, given that I really want this motor to get in and out of harbour, then sail, what am I missing in motor selection? Several vendors have recommended 20KW motors. That seems WAY overkill, though the same sheet promised me 8.2kts for 18KW, presumably to justify the recommendation of a 20KW motor, and the accompanying several extra thousand dollars. That's harsh actually. I do get that the power reqs go up exponentially with the kts. But where is the point of diminishing return? Do I really NEED the motor to get me to hull speed? Almost certain my Yanmar would not have done it. I get that in a pinch it would be nice to have the heavy duty HP. I try my best not to be in such situations, but of course if it happens I would be happy to have it...

So to my questions:

1) If I intend that 100A @ 48v will be my "cruising" speed, whatever I can get (sheet says just over 5kts at around 4KW), do I risk burning up the ME907, rated for just that (100A continuous at 48v)? This seems the perfect replacement for my diesel, as it mentions max RPM of 5000, and I never ran my diesel at much more than 2000RPM, and I intend to purchase thunderstruck's 2:1 reduction gears.

2) Assuming I go with my gut in 1) and get that small motor, do I risk any of the other components if I decide to "bigger" the motor later? I would get a controller to handle up to 20KW, if it is reasonable to expect that one controller could handle the range from 5KW to 20KW, and the battery bank I expect to be completely independent of these choices, other than to be able to handle the current ratings of the bigger motor (in which case I may add batteries to the bank when/if I bigger the motor).

and finally

3) Gear reduction is making my brain swim a bit. I get that direct drive is probably a bad idea for my tonnage (18,000lbs), but I haven't run across any solid advice/formulas for calculating ideal reduction. Can anyone explain? I actually like the look of the mount for the 2:1 product from thunderstruck, that looks like it will simply mount to the floor of the engine compartment, which I can pad with the right amount of... treated plywood(?) to align the existing shaft. Will certainly simplify coming up with something custom for the motor itself.

Fun to have a captive audience in the forum here. Looking forward to the conversation.

Cheers,

Jeff LaCoursiere
s/v Angels Quest

On 08/09/2013 08:45 PM, Robert Lemke wrote:

Nick,

Since Thunderstruck is just selling off the shelf components, your paying for their expertise in knowing these components. If you want to save coin, roll your own (or just copy their selection of components) go here http://www.cloudelectric.com/

Bob

From: Nick <chernikit@gmail.com>
To: electricboats@yahoogroups.com
Sent: Friday, August 9, 2013 6:32 PM
Subject: RE: [Electric Boats] Thunderstruck versus... well everyone else!

The cost increase is proportional to the cube of the LWL ;-)

Nick

From: electricboats@yahoogroups.com [mailto:electricboats@yahoogroups.com] On Behalf Of oak
Sent: Friday, August 09, 2013 3:39 PM
To: electricboats@yahoogroups.com
Subject: Re: [Electric Boats] Thunderstruck versus... well everyone else!

From what I've seen working with a C-22, and pondering for a C-30, I'd hate to have to pay for the batteries to power a Hunter 37!

Don't be discouraged. But as the boat gets bigger, the problems of electric power grow at a non-linear rate... Just like all other problems as the size of the boat gets larger. :)

Good Luck!!

From: Chris Hudson <clh5 _98@yahoo.com>
To: "electricboats@yahoogroups.com" <electricboats@yahoogroups.com>
Sent: Friday, August 9, 2013 4:58 PM
Subject: Re: [Electric Boats] Thunderstruck versus... well everyone else!

Jeff,

The reduction system will be the most challenging part of your project. With the size of your boat, unless you go higher than 48V, you will likely be in a 2 motor system. I went with Thunderstruck and I'm satisfied with what they provided and their support. Any more questions I'm happy to answer offline.

Chris

Sent from my iPhone

On Aug 8, 2013, at 16:33, "amdragonjeff" <jeff@jeff.net> wrote:

I've been researching for a few months trying to get a parts list and a budget together for converting my 1980 Hunter 37C. I think I have seen the full spectrum of fully complete kits with fancy mounting (Electric Yacht), POD drives (E-TECH), and even had a hand at Alibaba for sourcing individual parts from China, though that scares me more than a bit.

Then I ran across Thunderstruck. Not exactly an all-in-one kit, and it does seem that I will have to be a bit handy to get it mounted, but it doesn't seem too difficult. And they seem to be a good 1/3 of the cost of pretty much everything else.

Any reason I shouldn't go with them?

One thing I have had trouble finding *at all* are reviews of all these options. Happy customers? Sad customers? Found a few blogs, and to be fair have read three about using Electric Yacht that were very favorable of them. I'm surprised I couldn't find anything on people using POD drives, which when I started looking was what I thought I really wanted. Doesn't everyone want to get rid of that shadt hole below the waterline and say goodbye to the stuffing box forever? One of my most hated chores is packing that thing.

Anyway I am pretty near ordering time, and I am curious, being new to this forum, if anyone could tell me good or bad things about Thunderstruck. Or anyone else for that matter :)

Thanks!

Jeff LaCoursiere
s/v Angels Quest