Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 25-03-2014, 19:33   #1
Registered User
 
d design's Avatar

Join Date: Oct 2013
Location: Whangaroa, New Zealand
Posts: 242
So you have a big rubber band that goes up inside the mast and is conected to the prop shaft. You wind it up with shore power. and off you go. Almost no noise, no emissions, only a small amount of smoke, no oil changes, low maintinance, and no smell. No expensive heavy batteries. What do you reckon?
__________________

__________________
d design is offline   Reply With Quote
Old 25-03-2014, 20:49   #2
Senior Cruiser
 
Starbuck's Avatar

Cruisers Forum Supporter

Join Date: May 2005
Location: Long Beach, CA
Posts: 827
The End of EPIRBs

I guess if you got in trouble out there, you could reconfigure it into slingshot mode, and it would put you back on the beach.
__________________

__________________
s/y Elizabeth Catalina 34 MkII
"Man must have just enough faith in himself to have adventures, and just enough doubt of himself to enjoy them." G. K. Chesterfield
Starbuck is offline   Reply With Quote
Old 25-03-2014, 21:25   #3
Registered User
 
Panope's Avatar

Join Date: Sep 2012
Location: Washington State
Boat: Colvin, Saugeen Witch (Aluminum), 34'
Posts: 1,593
Re: rubber band propulsion

A decent effort was put forth to create a man carrying, rubber powered aircraft. The goal was to fly the length of a runway. Sadly, the effort was not successful.

A Chance to Unwind – CAFE Foundation Blog

Steve
Attached Thumbnails
Click image for larger version

Name:	rubber-bandit-528x351.jpg
Views:	88
Size:	41.5 KB
ID:	78105  
Panope is online now   Reply With Quote
Old 25-03-2014, 22:08   #4
Registered User
 
boat_alexandra's Avatar

Join Date: Aug 2009
Location: chesapeake bay
Boat: bristol 27
Posts: 2,824
Re: rubber band propulsion

the rubber band would have a very low energy storage, and add too much weight too high up. It would also wear out.


Instead consider a nickle titanium super spring low down in the boat (so you can remove some lead ballast to compensate) the energy capacity is still rather low, but the round trip efficiency is above 99% and this system could last hundreds of years, so cost is quite low. Because we don't need to generate a huge amount of power, just enough to navigate for a few miles, it is probably feasible, but the initial cost of the spring would be high as well as the customized systems required to efficiently utilize it.

Using lead acid batteries would likely be a more sensible storage option for a boat application. The spring is really only useful if you need to release/absorbe a huge amount of energy much faster than batteries can allow.
__________________
boat_alexandra is offline   Reply With Quote
Old 25-03-2014, 23:05   #5
Registered User
 
d design's Avatar

Join Date: Oct 2013
Location: Whangaroa, New Zealand
Posts: 242
Yeh but i like the idea of slingshot back to shore
__________________
d design is offline   Reply With Quote
Old 26-03-2014, 00:03   #6
Registered User
 
Terra Nova's Avatar

Join Date: Apr 2007
Location: Marina del Rey, California
Boat: Freya 39 cutter- Terra Nova
Posts: 3,652
ok

You were on the right track with the spring idea. But it is the rocking motion of the boat that causes a pendulum to advance one sprocket tooth, like in a huge clock, thus automatically winding the mainspring and storing energy for later release.

I once worked on a military project for a hand-operated generator; one straddled the frame and cranked it, somewhat like a bicycle, but by hand. Adapting this feature would allow you to operate a treadmill type device which would allow you to wind your spring or charge your boats batteries even when it was dead calm.
__________________
1st rule of yachting: When a collision is unavoidable, aim for something cheap.
"whatever spare parts you bring, you'll never need"--goboatingnow
"Id rather drown than have computers take over my life."--d design
Terra Nova is offline   Reply With Quote
Old 26-03-2014, 03:51   #7
Registered User

Join Date: Oct 2010
Location: Duluth, MN
Boat: Morgan 383
Posts: 129
Re: rubber band propulsion

How do you shoot yourselves anywhere with a sling shot? It's like blowing on your own sails. The physics don't work.

Since you're investigating alternative propulsion, why don't you consider a flywheel for energy storage? Regeneration could occur thru the use of a small IC engine or thru the prop. The mass could be kept low in the boat, displacing some of the ballast. Power companies are using them now and there have been workable designs for vehicles.
__________________
Dale Hedtke is offline   Reply With Quote
Old 26-03-2014, 05:26   #8
One of Those
 
Canibul's Avatar

Cruisers Forum Supporter

Join Date: Sep 2006
Location: Turks and Caicos Islands
Boat: Catalac 12M
Posts: 3,209
Re: rubber band propulsion

Wouldn't there be a gyroscopic effect on a flywheel that would cause some issues when the platform it was attached to ( your hull) tries to move in three axis?
__________________
Expat life in the Devil's Triangle:
http://2gringos.blogspot.com/
Canibul is offline   Reply With Quote
Old 26-03-2014, 06:05   #9
Senior Cruiser
 
atoll's Avatar

Cruisers Forum Supporter

Join Date: Mar 2010
Location: gettin naughty on the beach in cornwall
Boat: 63 custom alloy sloop,macwester26,prout snowgoose 37 elite catamaran!
Posts: 9,312
Images: 75
Re: rubber band propulsion

why not just get some sails and a mast
__________________
my catamaran building project updates http://www.cruisersforum.com/forums/...36#post2502136
atoll is offline   Reply With Quote
Old 26-03-2014, 06:06   #10
Moderator
 
HappyMdRSailor's Avatar

Cruisers Forum Supporter

Join Date: May 2008
Location: North Mississippi
Boat: 48 Wauquiez Pilot Saloon-C22 Chrysler Sunpiper- 19 Potter-Preparing to cruise w/my girl
Posts: 5,980
Re: rubber band propulsion

I thought for sure it was Jack who started this thread...
__________________
In the harsh marine environment, something is always in need of repair...

Mai Tai's fix everything...
HappyMdRSailor is offline   Reply With Quote
Old 26-03-2014, 06:07   #11
Moderator
 
HappyMdRSailor's Avatar

Cruisers Forum Supporter

Join Date: May 2008
Location: North Mississippi
Boat: 48 Wauquiez Pilot Saloon-C22 Chrysler Sunpiper- 19 Potter-Preparing to cruise w/my girl
Posts: 5,980
Re: rubber band propulsion

Quote:
Originally Posted by atoll View Post
why not just get some sails and a mast
Now that sounds pretty doable ???
__________________
In the harsh marine environment, something is always in need of repair...

Mai Tai's fix everything...
HappyMdRSailor is offline   Reply With Quote
Old 26-03-2014, 07:51   #12
Registered User
 
Dsanduril's Avatar

Join Date: Aug 2011
Location: South Pacific
Boat: Outremer 50S
Posts: 1,451
Re: rubber band propulsion

Check out:

The Windup Girl

and the others in Bacigalupi's future world. The whole world economy is based on food calories and high energy springs wound by giant elephants or waterwheels. And he has a pretty good (seems like) feel for the difficulties of getting a spring wound with significant energy.

I do like the idea for 20 minutes getting away from the dock, but suspect batteries and an electric motor are more practical.
__________________

__________________
Dsanduril is offline   Reply With Quote
Reply

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Electrical Propulsion vs Diesel Propulsion niel12 Multihull Sailboats 232 14-11-2014 17:51
Want To Buy: Mar-Gas LPG Tank V-Band Clamp YachtCalypso Classifieds Archive 0 05-04-2010 06:20
WTB: Sony ICF-SW7600GR World Band Receiver MarkJ Classifieds Archive 3 11-09-2009 12:25



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 08:09.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.