Re: [bolger]Best narrow "old time" hull for 18' to 23' electric boat (was Re: Plans)
[bolger]Best narrow "old time" hull for 18' to 23' electric boat (was Re: Plans)Hi Howard and All,
I was actually thinking of that hull except continue the sides parallel back to the stern (like the Sneakeazy) instead of the narrower transom. That would give more boyancy without increasing draft. Might even be able to put on a Tennassee style cabin.
I would be really curious about how that same size hull would perform with a sharpie bottom, a box keel bottom, a constant shallow V, a warped V, or the 2 chine hull like the Electron.
By the way, Howard, I noticed that you are aware that peak power of an electric moror is not peak efficiency from your previous post on the LEM. A lot of people forget that in selecting a motor/prop combo.
Thanks,
Ron
I was actually thinking of that hull except continue the sides parallel back to the stern (like the Sneakeazy) instead of the narrower transom. That would give more boyancy without increasing draft. Might even be able to put on a Tennassee style cabin.
I would be really curious about how that same size hull would perform with a sharpie bottom, a box keel bottom, a constant shallow V, a warped V, or the 2 chine hull like the Electron.
By the way, Howard, I noticed that you are aware that peak power of an electric moror is not peak efficiency from your previous post on the LEM. A lot of people forget that in selecting a motor/prop combo.
Thanks,
Ron
----- Original Message -----
From: Howard Stephenson
To:bolger@yahoogroups.com
Sent: Wednesday, July 13, 2005 4:23 PM
Subject: [bolger]Best narrow "old time" hull for 18' to 23' electric boat (was Re: Plans)
There are dozens of Michalak plans listed on the Duckworks website,
but Bob's Boat is not one of them.
Athttp://www.duckworksbbs.com/plans/jim/electron/index.htm
.. there is useful information for anyone thinking of building a small
electric boat.
Howard
[Non-text portions of this message have been removed]
There are dozens of Michalak plans listed on the Duckworks website,
but Bob's Boat is not one of them.
Athttp://www.duckworksbbs.com/plans/jim/electron/index.htm
.. there is useful information for anyone thinking of building a small
electric boat.
Howard
but Bob's Boat is not one of them.
Athttp://www.duckworksbbs.com/plans/jim/electron/index.htm
.. there is useful information for anyone thinking of building a small
electric boat.
Howard
--- Inbolger@yahoogroups.com, "Chris Stewart" <stewtone@m...> wrote:
> Michalak already has two designs that might suit, although neither
has
> a box keel. Electron, at 18x5 was designed for electric power. Bob's
> Boat, which he has discussed in his essays but may not yet be
> a "finished" design, is 20x6 and designed for a small 4stroke
outboard.
> It may be possible to convert it to electric.
--- Inbolger@yahoogroups.com, craig o'donnell <dadadata@f...> wrote:
a box keel. Electron, at 18x5 was designed for electric power. Bob's
Boat, which he has discussed in his essays but may not yet be
a "finished" design, is 20x6 and designed for a small 4stroke outboard.
It may be possible to convert it to electric.
Chris Stewart
> This sounds like a challenge Jim Michalak would like.Michalak already has two designs that might suit, although neither has
a box keel. Electron, at 18x5 was designed for electric power. Bob's
Boat, which he has discussed in his essays but may not yet be
a "finished" design, is 20x6 and designed for a small 4stroke outboard.
It may be possible to convert it to electric.
Chris Stewart
You might take a look at Lily to see PCB's hull design. She does about
4.5 knots with 70lb Minkota. Maybe you could stretch the hull with more
power abailable. One thing I have come to appreciate is the ability to
change trim by moving the batteries forward and back, particularly for
wind. Clyde
Ron Schroeder wrote:
4.5 knots with 70lb Minkota. Maybe you could stretch the hull with more
power abailable. One thing I have come to appreciate is the ability to
change trim by moving the batteries forward and back, particularly for
wind. Clyde
Ron Schroeder wrote:
> [bolger] Re: PlansHi John and Willers32,[Non-text portions of this message have been removed]
>
> I thought it would be good to change the subject line.
>
> I saw the electric cruiser in Wooden Boat. Beautiful!!! but to big
> for me. I am limited to 5.5' beam and between 18 n discussion:
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--- Inbolger@yahoogroups.com, "Nels" <arvent@h...> wrote:
Sneak' Idaho line. Great classic looks, slender. Google it up I
think.
> --- Inbolger@yahoogroups.com, Ron Butterfield <ronb_5@e...> wrote:Bolger's Lake Launch. Kinda a small Sneakeasy. Definitely in the
> > At 01:29 PM 7/12/05, Ron Schroeder wrote:
> >
> > >I saw the electric cruiser in Wooden Boat. Beautiful!!! but to
> big for
> > >me.
>
Sneak' Idaho line. Great classic looks, slender. Google it up I
think.
I have zero experience with the the boxed keel design but I would think it
would be harder to build than a shallow V or a warped V hull. Would a
boxed keel hull have more drag than than a V hull assuming they both had
enough rocker to just barely keep the transom at the water line?
Two thoughts.
This sounds like a challenge Jim Michalak would like.
A Sneakeasy - the plain sharpie style, very easy to build - would make the
most sense. 4 ft beam, 22+ ft long. You could remove 4 feet from the
midsection without affecting the stability, I'm quite sure.
--
Craig O'Donnell
Sinepuxent Ancestors & Boats
<http://freepages.genealogy.rootsweb.com/~fassitt/>
The Proa FAQ <http://boat-links.com/proafaq.html>
The Cheap Pages <http://www.friend.ly.net/~dadadata/>
Sailing Canoes, Polytarp Sails, Bamboo, Chinese Junks,
American Proas, the Bolger Boat Honor Roll,
Plywood Boats, Bamboo Rafts, &c.
_________________________________
-- Professor of Boatology -- Junkomologist
-- Macintosh kinda guy
Friend of Wanda the Wonder Cat, 1991-1997.
_________________________________
[Non-text portions of this message have been removed]
would be harder to build than a shallow V or a warped V hull. Would a
boxed keel hull have more drag than than a V hull assuming they both had
enough rocker to just barely keep the transom at the water line?
Two thoughts.
This sounds like a challenge Jim Michalak would like.
A Sneakeasy - the plain sharpie style, very easy to build - would make the
most sense. 4 ft beam, 22+ ft long. You could remove 4 feet from the
midsection without affecting the stability, I'm quite sure.
--
Craig O'Donnell
Sinepuxent Ancestors & Boats
<http://freepages.genealogy.rootsweb.com/~fassitt/>
The Proa FAQ <http://boat-links.com/proafaq.html>
The Cheap Pages <http://www.friend.ly.net/~dadadata/>
Sailing Canoes, Polytarp Sails, Bamboo, Chinese Junks,
American Proas, the Bolger Boat Honor Roll,
Plywood Boats, Bamboo Rafts, &c.
_________________________________
-- Professor of Boatology -- Junkomologist
-- Macintosh kinda guy
Friend of Wanda the Wonder Cat, 1991-1997.
_________________________________
[Non-text portions of this message have been removed]
I know nothing about electric motors, but that's not going to stop
me ;-]
The Lynch website indicates that the LEM-200 is the most powerful of
their motors; its maximum power output seems to be 2Kw at 1169 rpm
at 82% efficiency. Allowing for a little power loss in a simple
drive train, let's call it 2.5 shaft hp. That should be just about
enough to push a 20 ft. 1,000-lb hull to 6 kt You would do 5 kt with
half the power, giving you twice as much battery life. At 6 kt you
would have a speed/length ratio of 1.34, generally regarded as being
at the top end of displacement speed.
Because you have so little power you should aim for maximum
waterline length and minimum wetted surface area. An ideal shape
might be something like a canoe, although probably somewhat fatter
in the ends, particularly aft, for a fairly high prismatic
coefficient. Or maybe it could be a trimaran, if you can devise a
means of folding the outriggers in towards the side of the hull when
the boat is not in use.
A step hull will have more surface area than a non-step hull. Also,
a flat-bottomed chine hull will have more surface area than a round-
bottomed one of the same length and displacement.
If my early-morning calculations are correct, to get 1,000 lb.
displacement on a 20' hull, you'd need an underwater cross-sectional
area of 1.33 sq. ft., equivalent to, for example, a rectangle of 20"
x 10".
Just a few thoughts...
Howard
me ;-]
The Lynch website indicates that the LEM-200 is the most powerful of
their motors; its maximum power output seems to be 2Kw at 1169 rpm
at 82% efficiency. Allowing for a little power loss in a simple
drive train, let's call it 2.5 shaft hp. That should be just about
enough to push a 20 ft. 1,000-lb hull to 6 kt You would do 5 kt with
half the power, giving you twice as much battery life. At 6 kt you
would have a speed/length ratio of 1.34, generally regarded as being
at the top end of displacement speed.
Because you have so little power you should aim for maximum
waterline length and minimum wetted surface area. An ideal shape
might be something like a canoe, although probably somewhat fatter
in the ends, particularly aft, for a fairly high prismatic
coefficient. Or maybe it could be a trimaran, if you can devise a
means of folding the outriggers in towards the side of the hull when
the boat is not in use.
A step hull will have more surface area than a non-step hull. Also,
a flat-bottomed chine hull will have more surface area than a round-
bottomed one of the same length and displacement.
If my early-morning calculations are correct, to get 1,000 lb.
displacement on a 20' hull, you'd need an underwater cross-sectional
area of 1.33 sq. ft., equivalent to, for example, a rectangle of 20"
x 10".
Just a few thoughts...
Howard
--- Inbolger@yahoogroups.com, "Ron Schroeder" <rjs@b...> wrote:
> [bolger] Re: PlansHi John and Willers32,
>
> Propulsion would most likely be either a Lynch motor or the B$S
copy since I have a lot of experience with them in electric vehicles.
>
> I have zero experience with the the boxed keel design but I would
think it would be harder to build than a shallow V or a warped V
hull. Would a boxed keel hull have more drag than than a V hull
assuming they both had enough rocker to just barely keep the transom
at the water line?
--- Inbolger@yahoogroups.com, Ron Butterfield <ronb_5@e...> wrote:
shown in WB mag? E-teck motor and 4 golf cart batteries. Looks like
there is room for 4 solar panels on deck but to avoid steppin on
them, one would have to use the foward hatch to get to the ground
tackle.
Page three shows the hull immersement levels at 5500 lb
displacement. Looks like a really easily driven hull as both the
forward and stern sections are well above the water at their widest
beam width.
A samll simple rig or even a junk sail like on Applecross would add
to the performance and steadying affect in waves.
http://groups.yahoo.com/group/bolger4/files/Small%20Motorsailer/
Cheers, Nels
> At 01:29 PM 7/12/05, Ron Schroeder wrote:big for
>
> >I saw the electric cruiser in Wooden Boat. Beautiful!!! but to
> >me.Anybody care to speculate how this boat would work with the set-up
shown in WB mag? E-teck motor and 4 golf cart batteries. Looks like
there is room for 4 solar panels on deck but to avoid steppin on
them, one would have to use the foward hatch to get to the ground
tackle.
Page three shows the hull immersement levels at 5500 lb
displacement. Looks like a really easily driven hull as both the
forward and stern sections are well above the water at their widest
beam width.
A samll simple rig or even a junk sail like on Applecross would add
to the performance and steadying affect in waves.
http://groups.yahoo.com/group/bolger4/files/Small%20Motorsailer/
Cheers, Nels
At 01:29 PM 7/12/05, Ron Schroeder wrote:
For an example of what you are trying to do, how about looking at these pages?
http://www.psnw.com/~jmrudholm/etekoutboard.html
The Sneakeasy design has been scaled both up and down, so you could get the
length where you want it. You could put a surry top on like the Lake
Launch, with the solar panels on top of it.
One drawback of electric power in a boat of this type is the weight of the
batteries. If your range requirements are moderate, you might be able to do
very well.
Regards,
RonB
>I saw the electric cruiser in Wooden Boat. Beautiful!!! but to big forI would expect so, at least until you had enough power to get up on plane.
>me. I am limited to 5.5' beam and between 18 and 23 feet long with
>preferably the 18 foot end of the range due to dock slip fees.Propulsion
>would most likely be either a Lynch motor or the B$S copy since I have a
>lot of experience with them in electric vehicles.
>
>My experience with converting sailboats to electric shows that a S/L ratio
>of almost 2 is possable with something more powerfull than a trolling motor.
>I have zero experience with the the boxed keel design but I would think it
>would be harder to build than a shallow V or a warped V hull. Would a
>boxed keel hull have more drag than than a V hull assuming they both had
>enough rocker to just barely keep the transom at the water line?
For an example of what you are trying to do, how about looking at these pages?
http://www.psnw.com/~jmrudholm/etekoutboard.html
The Sneakeasy design has been scaled both up and down, so you could get the
length where you want it. You could put a surry top on like the Lake
Launch, with the solar panels on top of it.
One drawback of electric power in a boat of this type is the weight of the
batteries. If your range requirements are moderate, you might be able to do
very well.
Regards,
RonB
[bolger] Re: PlansHi John and Willers32,
I thought it would be good to change the subject line.
I saw the electric cruiser in Wooden Boat. Beautiful!!! but to big for me. I am limited to 5.5' beam and between 18 and 23 feet long with preferably the 18 foot end of the range due to dock slip fees. I like the vertical or near vertical sides and near vertical stem above the waterline. Initially I plan to run the boat open but eventually plan to build a light cabbin for protection from the weather and sun and also to mount solar panels.
Propulsion would most likely be either a Lynch motor or the B$S copy since I have a lot of experience with them in electric vehicles.
My experience with converting sailboats to electric shows that a S/L ratio of almost 2 is possable with something more powerfull than a trolling motor.
I have zero experience with the the boxed keel design but I would think it would be harder to build than a shallow V or a warped V hull. Would a boxed keel hull have more drag than than a V hull assuming they both had enough rocker to just barely keep the transom at the water line?
I thought it would be good to change the subject line.
I saw the electric cruiser in Wooden Boat. Beautiful!!! but to big for me. I am limited to 5.5' beam and between 18 and 23 feet long with preferably the 18 foot end of the range due to dock slip fees. I like the vertical or near vertical sides and near vertical stem above the waterline. Initially I plan to run the boat open but eventually plan to build a light cabbin for protection from the weather and sun and also to mount solar panels.
Propulsion would most likely be either a Lynch motor or the B$S copy since I have a lot of experience with them in electric vehicles.
My experience with converting sailboats to electric shows that a S/L ratio of almost 2 is possable with something more powerfull than a trolling motor.
I have zero experience with the the boxed keel design but I would think it would be harder to build than a shallow V or a warped V hull. Would a boxed keel hull have more drag than than a V hull assuming they both had enough rocker to just barely keep the transom at the water line?
----- Original Message -----
From: willers32
To:bolger@yahoogroups.com
Sent: Tuesday, July 12, 2005 9:47 AM
Subject: [bolger] Re: Plans
Check the current issue of Wooden Boat. There's an electric cruiser in
there that is based on Bolger's Tennessee. The builder added a box
keel, like the step sharpies. The box keel adds enough underwater
volume to handle the added weight of a ton of batteries.
Just something to think about.
--- Inbolger@yahoogroups.com, "John Bell" <smallboatdesigner@m...> wrote:
> Six knots with electric power may be tough to acheive, except for
very short
> bursts. You'll need lots of battery power to go that fast, which
adds weight
> which makes it harder to go that fast. Unity speed (SQRT(WL)) is about 5
> knots, which is probably the top end of what you could expect with
> reasonable electric power.
>
> What motor would you use? On of the new B&S 3 HP jobs?
[Non-text portions of this message have been removed]