# Multiple functions on single rope ?

Discussion in 'Boat Design' started by Externet, Mar 27, 2014.

1. Joined: May 2009
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### ExternetJunior Member

Hi all.
For this contraption propelled by seawaves, the single linking rope/cable should provide multiple functions. Do you think it is achieavable ?

----> http://i588.photobucket.com/albums/ss323/Innernet/P1010381_zps560efe3d.jpg

A boat rides on seawaves, pulling and easing a 'ballast' meant to provide forward motion towing the boat. The 'ballast' is to be at least half crest wavelenght depth.

-Pull 'ballast' up on crests,
-Ease 'ballast' down on its weight at troughs,
-Tow boat behind,
-Keep 'ballast' as horizontal as possible,
-Steer 'ballast' to heading desired by boat rudder

The rope tie points locations play a role, the sketched rope connects to a roller at its lower end, but may be made different. The sea surface will present different wavelenghts and heights.

Roller stops can be implemented on the 'ballast' ^ hanger, the steering could work if the nose of the ballast is the one being pulled to change heading...

<The ballast functionality and operation principle is not in discussion of this post, but it converts the up/down motion to 'jet' thrust>

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### gonzoSenior Member

Looking at your design, I would guess that the hull will have waves breaking over it. The huge surface area of the ballast will stop it from heaving. It will not ride but plow through waves.

3. Joined: May 2009
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### ExternetJunior Member

Thanks, gonzo.
The simple sketch is not meant to show the 2 flap valves on the whole top and bottom areas of the 'ballast'; and not part of the discussion. Just assume the effort to pull it does not reach plowing forces; or if preferred, a closed hermetic deck on the boat where plowing does not cause it to capsize, keeping it always buoyant.

Opinions on the multifunctionality of a single rope is what am after.

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### waikikinSenior Member

Eternet,
I think your ballast needs a flywheel within, then you can store some energy while at the mooring too & a sprung ratcheting drive off the boat rope, which drives the flywheel which drives a propeller which pulls the boat, your going to need controls for Fwd/Neutral?Rev & steering.
The rope will definatly work in attaching the two objects so long as it's strong enough.
Best thing would be to build it to prove the concepts, maybe at dinghy size to limit the cost if it don't go too well.
Jeff

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### ExternetJunior Member

6. Joined: Jan 2006
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### waikikinSenior Member

7. Joined: May 2009
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### ExternetJunior Member

Elegant, and works without any of your proposed ratcheting, transmissions, flywheel, propeller engineering visions...

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