Retractable Rope

[fireeag1e]

Hello, I am a high school student enrolled in an engineering class. The project for the whole year is to design and build a prototype to solve a problem.

As a rabid water-skier, I instinctively looked at solving a problem in water sports. My idea is to create a device to retract a tow rope. This in my opinion would make organizing ropes to bring up multiple skiers much easier. Also, I feel that this would prevent annoying tangles during storage of ropes.

A rough idea of how I would go about making this is similar to a retractable tape measure using a tension system. I feel it would definitely need to have a lock mechanism at its fully extended position so, while in use, it could act as a normal rope.

In this thread, I was just looking for more input from of other skiers and whether a desire for such a product is tangible. Since this topic isn't totally finalized if people want to shout in some other ideas for problems, I'm all ears.

 

[sasto]

Re: Retractable Rope

Maybe start with one of those air hose roller upper things. They are spring loaded and can hold alot of line.

If you want electric....maybe a winch.

Have Fun!

 

[haulnazz15]

Re: Retractable Rope

I'm not sure what problem you are trying to "solve". Is there an issue with leaving the tow rope in the water? Seems like it would be a major PITA to have to have someone unreel the rope back out once you let go or fell as opposed to just letting it remain out in the water. I think if you could choose whether or not it would retract from inside the boat (via a switch) it would be better. Sometimes I'm in the water adjusting a binding or waiting on a wave to pass, and don't have my hand on the rope . . . that would cause your tension-mechanism to retract the rope and really **** me off!

 

[biddle1950]

Re: Retractable Rope

I have seen in ski shows they use winches to correct rope length when building pyrimids and in multiple skier situations.

 

[skibrain]

Re: Retractable Rope

Do some google searches. There are 8-10 similar ideas or designs that are out there. I've seen some advertised over the years, but never seen one in use. Maybe it will suggest that someone has already accomplished what you are thinking about, or maybe your concept is completely different.

http://waterski.about.com/library/weekly/bl_042202skikreel.htm

http://www.patentgenius.com/patent/D334960.html

For aggressive slalom skiing we ski off a center pylon in an inboard ski boat. This involves some pretty extreme loads and selecting from different specific rope lengths before each run. In order for it to be strong enough it would have to be heavily built. I would be concerned if the spool mechanism and it's weight were between the pylon attachment point and the handle. It would seem cumbersome as it swings back and forth in about a 120 degree arc as the skier swings from side to side.

While loads are sometimes high, the rope sometimes goes slack and is snapped tight. What happens to the retractable device in this situation? Does it bounce around and hit the pylon? Does the spool rigid-mount to the pylon or boat and pivot with the a swivel head on the pylon?

We get about one season out of a high-quality $60 ski line. Wear and tear at the most frequently used take-off loops is the earliest wear area, but from a safety standpoint we just replace on a regular basis. Would a recoil rope require the owner to reload with a custom "rope refill" from the manufacturer? or would any old ski rope work?

Just a few thoughts.

 

[LippCJ7]

Re: Retractable Rope

Maybe have it cartridge loaded, if you want a smaller or longer rope place a different cartridge in it? that way the rewind function stays in place, you could have a tube cartridge or a couple ski cartridges or a wakeboard cartridge? That would be easier then looking for ropes in a pile! I have about six ropes in my boat and no matter how I secure the ropes they get tangled eventually, cartridges could fix this issue as well. I have a rule on my boat stay out of the rope compartment!!

 

[Starcraft Enterprise]

Re: Retractable Rope

These have been around about 35 years. I just junked and scrapped a boat 2 weeks ago that had 2 of these devices. They was mounted on the inside of the transom. The boat was a 1969 Mark Twain. The devices I believe were from the mid seventies.
The starboard one was similar to a retractable cord reel called a ski rein. It kept constant spring pressure on the rope to retract. To prevent unwanted retraction there was a clamp lock device on the outside of the transom.
The port one also retracted thru the transom and was electric. It simply unwound by pulling on the rope and retracted by running a small electric motor.
Here are some pics I took as I was tearing it apart.

Old Ski Rein advertisement
http://books.google.com/books?id=Hw...&ved=0CEwQ6AEwCA#v=onepage&q=ski rein&f=false