T-Pain Is On A Boat: Re: [Electric Boats] monohull performance

Thursday, October 24, 2013

Re: [Electric Boats] monohull performance

Interesting....

I have a small 14' wooden runabout that is currently powered with a (VERY HEAVY) Nissan 30HP 4-stroke.

I have always wondered how fast it would go with my Torqeedo 4R. The boat planes at about 13mph, and hits a top speed of ~22mph with the 30hp motor.

Based on what you're saying, if the max theoretical speed of the torqeedo prop is only 18mph, I'd be very lucky if I could get my small boat up on plane??

From: Robert Lemke <robert-lemke@att.net>
To: "electricboats@yahoogroups.com" <electricboats@yahoogroups.com>
Sent: Thursday, October 24, 2013 3:31 PM
Subject: Re: [Electric Boats] monohull performance

Ned,

Thanks for sharing your specs. Have you run the test on one Cruise 4.0? The reason I ask is I'm thinking with the numbers you produced with (2) 4.0's there might have been some interaction between the props. I also use LiFePO4 cells and for a 48 volt motor I use (16) cells in series for 51.2 volts. Your (18) cells produces 57.6 volts so about 11% more rpm. The V30 prop with no slip would have a speed of 30 kmph (18.3 mph) at standard voltage or 20.3 mph at your voltage. Slip with these numbers is 21% which is low for a conventional high revving prop for a gasoline outboard but IMHO a bit high for the purpose designed Torqeedo prop. I could be out in left field on this not knowing the drag of your hull, but Torqeedo prides themselves on their 1300 rpm prop design.

Bob

From: Ned Farinholt <nedfarinholt@comcast.net>
To: electricboats@yahoogroups.com
Sent: Thursday, October 24, 2013 12:40 PM
Subject: [Electric Boats] monohull performance

Tom,

Thanks for sharing the performance information on your electric launch.

Here is an update on my runabout now that I have added a second motor and battery bank. These runs were made on a nearby lake.

overall length : 19 ft; beam 54 in.

water line length: 18 ft
total weight including one pilot is about 900-1000 lbs; 300 hull, 100 motors, 350 batteries, 150 pilot, 15 charger, 10 LA 12v, etc
motors are Twin Torqeedo Cruise 4R
props: Torqeedo high pitch
water: 69 deg F fresh water
wind less than 5 mph
water surface smooth
batteries: 18 cell 160 ah LiFePO4 plus 18 cells 100 ah LiFePO4 for a total of about 15kwh.

Combined power to both engines kw--mph (average of two way runs)

0.6kw--5.1mph
1.0--6.1
2.0--7.8
3.0--9.5
4.0--11.0
5.0--12.5
6.0--13.8
7.0--15.0
8.0--16.0

Adding another crew of 150 - 200 lbs reduces the speed on plane by about 1mph.

I ran this boat in the 24 mile Wye Island Electric Boat Marathon but hit a submerged object near the beginning of the race and came in third with one engine and carrying another passenger. Photos of the race participants can be seen at http://jpbliss.smugmug.com/Boats/Wye-River-Electric-Boat-2013/32366923_v5hNPr#!i=2817852500&k=WhCXZpN

To compare to yours and Steve's data, mine should run at 6 knots for about 6 hours or at 5 knots for 12 hours using 12kwh of battery.

Ned

On Oct 24, 2013, at 10:51 AM, <boat_works@yahoo.com> wrote:

Hi Steve,
Running a 20' monohull "all day" at six knots using four FLA GC batteries (probably 220Ah max) is astonishing.

You have perhaps 5kWh of energy on board, and pushing a boat like this to that speed could easily take 2.5kW, meaning that if you ran the bank down to full discharge, you'd be likely to have a bit more than two hours run time. Actually, less, since the Peukert Effect hasn't been factored in.

Do you have "Watts per knot" data to share? I'd be particularly interested to know power consumption at 4, 5, and 6 knots. You can see the performance of my launch at: http://www.grapeviewpointboatworks.com/chart.html

-Tom

---In electricboats@yahoogroups.com, <electricboats@yahoogroups.com> wrote:

I have a Duffy 20 named Sparky, posted pics in folder named "Sparky". Ours is unique in that its an outboard drive unit. I use the Torqueedo 2.0 cruise. Boat is unbelievably quiet, we operate on 4 6v deep cycle batteries from Costco. We can cruise all day at 6 knots. I'm charging with solar at home might mount the panels on the boat but looking at flexible panels now available on ebay. We'd mount them to the roof. Boat is stored on trailer near home so I use external panels from garage roof. Duffy's are the original electric boat ours was built in the 70's.

Steve

---In electricboats@yahoogroups.com, <matwete@...> wrote:

Sent to the moderator...

-----Original Message-----
From: electricboats-owner@yahoogroups.com
[mailto:electricboats-owner@yahoogroups.com] On Behalf Of Dag Hanssen
Sent: Tuesday, September 24, 2013 6:58 AM
To: electricboats-owner@yahoogroups.com
Subject: Duffy....?

Hi from Fort Lauderdale.
I purchased a used Duffy Balboa a few weeks ago, bit it does not run,
working on having the controller tested, should know in a few days.
Has anybody fitted Solar Panels to their Duffys?
If so what size?
What is the current draw from the 48 Volt motor?
I have 8 golf cart batteries and the brochure talks about a 15 hr endurance,
sounds high, would that be with an optional larger bank of say 12 or 16
batteries?
Not much tech info on the Duffy site, looking for help from other owners.
Thanks
Dag

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