Saturday, June 30, 2012

Re: [Electric Boats] Pulsing Action

 

It could be reduced or even eliminated by "tightening" your rudder/tuller assembly with shims or bushings. Also consider a four-blade prop which is generally smoother and better balanced. My 2c.

George Johnson

On Sun, Jul 1, 2012 at 12:45 AM, Kevin Pemberton <pembertonkevin@gmail.com> wrote:
 

Are you talking about prop wash?  I bet you are. It is caused by the swirl the prop causes, is no cure that I know of.

Kevin Pemberton

On 06/28/2012 03:54 PM, Matthew Geier wrote:

 

My launch gets a small 'shudder' in the rudder at certain speeds too.
The boat has probably always done this, but with the vibration of the
old engine, you would have never noticed.
On my boat the rudder/tiller assembly is quite 'loose'. I imagine at
certain prop speeds a resonance gets set up in the rudder/tiller system.
The prop is a 3 blader and it's behind a full keel.





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No trees were harmed in the creation of this message, though a significant number of electrons may have been inconvenienced.

George Johnson
GeoMar Logistics
Jomtien, Chonburi
Thailand

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Re: [Electric Boats] Re: Maiden voyage!

 

Hi Skip,
 
I have some I took through the project. Hope to have time to a folder together soon. Going sailing tomorrow!
 
Fred
 

From: Skip von Niederinghausen <farharbour@gmail.com>
To: electricboats@yahoogroups.com
Sent: Tuesday, June 26, 2012 2:24 PM
Subject: Re: [Electric Boats] Re: Maiden voyage!

 
Any photos of your boat and motor installation?

On Tue, Jun 26, 2012 at 12:33 PM, danbollinger <no_reply@yahoogroups.com> wrote:
 
Nice. What river and how fast does the current run?


--- In mailto:electricboats%40yahoogroups.com, "fred4936" <fred4936@...> wrote:
>
> Hello All,
>
> We had our maiden voyage last Sat., and eevrything went very well! We powered out of the slip, and down the river. We hoisted sails, then turned it off. We got to our creek, and powered up again. It went up to the marina and we manuevered into our slip. Just like it was supposed to!
>
> Fred Liesegang
> Tartan 27-2 Eagle
>




--
"One  should always remember that it is Bruce Wayne who is the  fictional character, a myth, hiding in  a mask of  normality, Batman is real"
From  a conversation  with  a  French  friend


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Re: [Electric Boats] Re: Maiden voyage!

 

Hi Dan,
 
We motored out of the Patchogue River. Calling it a "river" is probably being generous, since it isn't that big, maybe 200' wide. It is tidal with not much of a range, compared to many other places, so current isn't a major factor, unless there are issues I am unaware of. The time we were there I didn't feel a current either helping or hindering our progress. We may go back up the during the season for some of the restaurants along it's banks.The boat now lives on an even smaller strip of water with about 1' of range.
 
Fred
 

From: danbollinger <no_reply@yahoogroups.com>
To: electricboats@yahoogroups.com
Sent: Tuesday, June 26, 2012 12:33 PM
Subject: [Electric Boats] Re: Maiden voyage!

 
Nice. What river and how fast does the current run?

--- In mailto:electricboats%40yahoogroups.com, "fred4936" <fred4936@...> wrote:
>
> Hello All,
>
> We had our maiden voyage last Sat., and eevrything went very well! We powered out of the slip, and down the river. We hoisted sails, then turned it off. We got to our creek, and powered up again. It went up to the marina and we manuevered into our slip. Just like it was supposed to!
>
> Fred Liesegang
> Tartan 27-2 Eagle
>



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Re: [Electric Boats] Re: Maiden voyage!

 

Hello Mark,
 
Thank you! I have the 8.5 kw Thunderstruck kit. I haven't installed gauges yet, so I don't have data. I hope to have them installed this week. I am curious myself! The trip out to the bay is only about 15 minutes each way, so I am more curious than concerned. With the prevaiing wind, I could get back to the dock under sail if we had to. It is for non-prevailing that I need the motor. Later on when we start going further and needing it more, we will need this data! Will post as soon as I have something meaningful.
 
Fred
 

From: acsarfkram <acsarfkram@yahoo.com>
To: electricboats@yahoogroups.com
Sent: Tuesday, June 26, 2012 12:43 PM
Subject: [Electric Boats] Re: Maiden voyage!

 
Very cool Fred. What system did you install? Do you have any numbers for us, amp or watt usage at different speeds?

Mark
Santa Cruz

--- In mailto:electricboats%40yahoogroups.com, "fred4936" <fred4936@...> wrote:
>
> Hello All,
>
> We had our maiden voyage last Sat., and eevrything went very well! We powered out of the slip, and down the river. We hoisted sails, then turned it off. We got to our creek, and powered up again. It went up to the marina and we manuevered into our slip. Just like it was supposed to!
>
> Fred Liesegang
> Tartan 27-2 Eagle
>



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Re: [Electric Boats] Pulsing Action

 

Are you talking about prop wash?  I bet you are. It is caused by the swirl the prop causes, is no cure that I know of.

Kevin Pemberton

On 06/28/2012 03:54 PM, Matthew Geier wrote:

 

My launch gets a small 'shudder' in the rudder at certain speeds too.
The boat has probably always done this, but with the vibration of the
old engine, you would have never noticed.
On my boat the rudder/tiller assembly is quite 'loose'. I imagine at
certain prop speeds a resonance gets set up in the rudder/tiller system.
The prop is a 3 blader and it's behind a full keel.


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Thursday, June 28, 2012

Re: [Electric Boats] 48 volt 1000ah pack.

 

NICE!!
 
You learn from your mistakes...Today I hope not to learn_too_ much. 

From: James Sizemore <james@deny.org>
To: electricboats@yahoogroups.com
Sent: Thursday, June 28, 2012 8:17 PM
Subject: [Electric Boats] 48 volt 1000ah pack.

 
I thought I would give my experience with the new US distributor of Winston LiFePo cells: Balqon. So far I am very happy with them. My 1472 pound 48kw LiFePo pack shipped to my marina in five days, from the time I ordered. (I have had Amazon orders take longer) They came in wooded crates with plenty of padding. So they get high marks in the shipping department. The shipper even broke one of the pallets so I am glad they where well packed.

I ordered 16 1000ah cells: http://www.balqon.com/store.php#ecwid:category=2736691&mode=product&product=11905253
They offer a five year warranty on the above web site, I am not sure what that covers and they did NOT include any written warranty card with the cells. I did some research on the company before I made an order this expensive. It is publicly traded so who knows they might even be around long enough to honor any warranty claims. They did include instructions on how to do the first charge. Apparently I need to charge them "slowly" under (.5CA) the first time to 4 volts.

The cells where damn heavy over 90 pounds apiece, it took me half the afternoon to get them all on the boat. They are on the back deck and my bow is now sitting a little high ;-)

I know few of you will be ordering packs this big, I have to feed two Electric Yacht 360ibl's. But they do have some smaller cells with built in CAN bus controlled BMS: http://www.balqon.com/store.php#ecwid:category=2897128&mode=product&product=12658249
That might be a good fit for some of you.

Next step in my project is building the battery boxes, testing each cell, and installing the BMS. You can follow my slow slow progress here http://www.deny.org



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[Electric Boats] 48 volt 1000ah pack.

 

I thought I would give my experience with the new US distributor of Winston LiFePo cells: Balqon. So far I am very happy with them. My 1472 pound 48kw LiFePo pack shipped to my marina in five days, from the time I ordered. (I have had Amazon orders take longer) They came in wooded crates with plenty of padding. So they get high marks in the shipping department. The shipper even broke one of the pallets so I am glad they where well packed.

I ordered 16 1000ah cells: http://www.balqon.com/store.php#ecwid:category=2736691&mode=product&product=11905253
They offer a five year warranty on the above web site, I am not sure what that covers and they did NOT include any written warranty card with the cells. I did some research on the company before I made an order this expensive. It is publicly traded so who knows they might even be around long enough to honor any warranty claims. They did include instructions on how to do the first charge. Apparently I need to charge them "slowly" under (.5CA) the first time to 4 volts.

The cells where damn heavy over 90 pounds apiece, it took me half the afternoon to get them all on the boat. They are on the back deck and my bow is now sitting a little high ;-)

I know few of you will be ordering packs this big, I have to feed two Electric Yacht 360ibl's. But they do have some smaller cells with built in CAN bus controlled BMS: http://www.balqon.com/store.php#ecwid:category=2897128&mode=product&product=12658249
That might be a good fit for some of you.

Next step in my project is building the battery boxes, testing each cell, and installing the BMS. You can follow my slow slow progress here http://www.deny.org

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[Electric Boats] open source motor controller

 


144  V 1000 A max
 
You learn from your mistakes...Today I hope not to learn_too_ much. 

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Re: [Electric Boats] launched launch

 

Welton

Welcome to the electric fleet.

Capt. Mike

Sent from on board BIANKA
http://biankablog.blogspot.com
From: Welton Rotz <welton@weltonrotz.com>
Sender: electricboats@yahoogroups.com
Date: Thu, 28 Jun 2012 16:02:49 -0700
To: <electricboats@yahoogroups.com>
ReplyTo: electricboats@yahoogroups.com
Subject: [Electric Boats] launched launch

 

I have just launched my 18 ft. electric launch. It worked GREAT

Will do hull speed at 75% Has a 36 volt system

Prop is 12 X 8 Would like to have had a larger prop, but no room

name: " my CURRENT boat"

I would like to thank Arby and his crew at AMeP for all their help in setting up my system.

Also, ARC Battery in Sausalito. CA who made different size batteries available for me to

see which would fit the best in the bilge. I made plywood and cardboard models to try for fit.

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[Electric Boats] launched launch

 

I have just launched my 18 ft. electric launch. It worked GREAT

Will do hull speed at 75% Has a 36 volt system

Prop is 12 X 8 Would like to have had a larger prop, but no room

name: " my CURRENT boat"

I would like to thank Arby and his crew at AMeP for all their help in setting up my system.

Also, ARC Battery in Sausalito. CA who made different size batteries available for me to

see which would fit the best in the bilge. I made plywood and cardboard models to try for fit.

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Re: [Electric Boats] Pulsing Action

 

My launch gets a small 'shudder' in the rudder at certain speeds too.
The boat has probably always done this, but with the vibration of the
old engine, you would have never noticed.
On my boat the rudder/tiller assembly is quite 'loose'. I imagine at
certain prop speeds a resonance gets set up in the rudder/tiller system.
The prop is a 3 blader and it's behind a full keel.

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Wednesday, June 27, 2012

Re: [Electric Boats] Pulsing Action

 

Look for articles on twisted rudders

Deals with this issue in exactly the same way stators in ducted fans are shaped to conform to the angled air flow from the fan blades - the benefit is improved efficiency and reduce noise and vibration . US Navy had frigates it did this with also.

Electrics are very responsive to efficiency improvements with resultant drop in amp draws giving longer run time or improved performance

However from what I have seen a wholesale rethink of props would achieve far more

Andrew

 

On 28/06/2012 11:11 AM, Arby bernt wrote:
 
Hi Anne,
I was describing some force transmitted up the tiller, perhaps an oscillation induced by the twin rushes of water off the prop as it spun. I think this is because the prop blades and rudder are not parallel (or prop shaft perpendicular to the rudder, for example) in our Ericson 27 test boat. This allows for a timing discrepancy in the arrival of the pulses of water from the prop blades. The tiller would waddle. It was unnerving. I don't think this would be a problem in a full keel boat, as the rudder axis is usually closer to normal relative to the prop shaft. 

Cavitation only occurred under peak output. 

The MaxProp is quite a nice piece of engineering, and I'll try a three-blade version when sailing becomes more important then demonstrating an electric drive. 

Be Well,
Arby

From: amracel <amracel@stuffandjunk.net>
To: electricboats@yahoogroups.com
Sent: Wednesday, June 27, 2012 7:41 PM
Subject: [Electric Boats] Pulsing Action

 
Arby (or anyone else with a bit of knowledge), can you explain what you meant by '... a pulsing action against the rudder' with your 2-bladed MaxProp. I've had some issue with some sort of vibration. I've taken care of what appeared to be cavitation, but there's still something else going on. I haven't been sure if I'm noticing it because the electric engine is quieter and vibrates less than my diesel did or if something else is going on. So I'm just curious what your experience was since I also have a 2-bladed MaxProp.

Anne Racel
CAL 2-29
4 Degrees





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Re: [Electric Boats] Pulsing Action

 

Hi Anne,
I was describing some force transmitted up the tiller, perhaps an oscillation induced by the twin rushes of water off the prop as it spun. I think this is because the prop blades and rudder are not parallel (or prop shaft perpendicular to the rudder, for example) in our Ericson 27 test boat. This allows for a timing discrepancy in the arrival of the pulses of water from the prop blades. The tiller would waddle. It was unnerving. I don't think this would be a problem in a full keel boat, as the rudder axis is usually closer to normal relative to the prop shaft. 

Cavitation only occurred under peak output. 

The MaxProp is quite a nice piece of engineering, and I'll try a three-blade version when sailing becomes more important then demonstrating an electric drive. 

Be Well,
Arby

From: amracel <amracel@stuffandjunk.net>
To: electricboats@yahoogroups.com
Sent: Wednesday, June 27, 2012 7:41 PM
Subject: [Electric Boats] Pulsing Action

 
Arby (or anyone else with a bit of knowledge), can you explain what you meant by '... a pulsing action against the rudder' with your 2-bladed MaxProp. I've had some issue with some sort of vibration. I've taken care of what appeared to be cavitation, but there's still something else going on. I haven't been sure if I'm noticing it because the electric engine is quieter and vibrates less than my diesel did or if something else is going on. So I'm just curious what your experience was since I also have a 2-bladed MaxProp.

Anne Racel
CAL 2-29
4 Degrees



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[Electric Boats] Pulsing Action

 

Arby (or anyone else with a bit of knowledge), can you explain what you meant by '... a pulsing action against the rudder' with your 2-bladed MaxProp. I've had some issue with some sort of vibration. I've taken care of what appeared to be cavitation, but there's still something else going on. I haven't been sure if I'm noticing it because the electric engine is quieter and vibrates less than my diesel did or if something else is going on. So I'm just curious what your experience was since I also have a 2-bladed MaxProp.

Anne Racel
CAL 2-29
4 Degrees

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