Lifetime guaranteed elastic...

Rcsailing.net How To ?
21

Here is a snapshot of the traveler assembly. I will try it and see.

I looked at pony tail loops but the ones I found were closed with metal clasp, sort of a crimp with teeth. My most recent elastic failure occured right at the crimp, it appears, so the crimp is a problem area. In any event, here is the solution I am using.

The “crimps” in the photo are cut from heat-shrink tubing for electrical applications. The crimps are not shrunk, just slipped onto the doubled elastic. And they are pretty soft, so they should not knife into the elastic.

The thimbles I had from GBMY were a little too wide for the Pekabe elastic, so I used instead these two brass thimbles cut from a U-control line spool. The idea is to avoid point stress on the elastic.

Thank you for all your input and ideas on this problem. It is such an absurd little thing to sit down and ponder on a winter night – and yet, it is so often that tiny 10-cent O-ring that costs the Grand Prix.

Regards, Michael

22

mcg,

I use stainless split rings and various snap fittings from the fishing supply store at all the attachment points.

23

i know this is not the idea behind this. but have you ever thought about using a trolley system on your winch? there is no elastic needed for that. and I have been using that on my IOM for years. otherwise i should just keep my mouth shut. as i realy dont have an idea
good luck
cougar

24

I was thinking about away to eliminate the elestic completely, and thought of a two-wheeled take-up system, like there is on a bicycle derailler. It requires wheels on a plate and a spring to pivot the second wheel around the first to take up the slack. The line would go in an S-shape around the wheels. Cassette tape recorders/players use something like this to keep pressure on the drive belt, so maybe that would be a source for a ready-made part.

It should last forever, IMO, unless it gets rusty or something.

25

I have attached pics of how I use a bowsie to tension winch line. It has been this way for a long time without incident. I have found dacron with a bit of stretch is best as it seems to hold far better than spectra.

The advantages of this is its light, easy to adjust and very simple.

26

Why not just use a stainless spring…?

SAILSetc do sell them for this application and I have seen them used on quite a lot of yachts, including mine. :slight_smile:

27

Stainless is an excellent solution. I didn’t know they offered it.

Notice that all of these system, including those for which there is no elastic, have some sort of built-in elasticity. It is in the line, or in the spring loading for the idler pulley, or in the pony tail loop or whatever. Why?

It seemed to me that keelhauled nailed it when he talked about the variation in the winch drum’s effective diameter.

Fully wound, a winch drum has a larger effective diameter than it does when it is almost empty.

Let’s take the case a of trolley system that is near the end of its travel, that is, nearly close hauled. Futher, let’s say the inner drum is dispensing string, and the outer drum is gathering it in.

The outer drum is almost fully wound up, but the inner drum is nearly empty, unwound. The outer drum is therefore fat with string and has a large effective diameter.

But the inner drum, nearly empty, has an effective diameter that is almost the smallest it can become, a hair larger than the diameter of the drum itself.

Now suppose the drum takes another half turn. Notice that because of the difference in effective diameters, the outer drum gathers in more string than the inner drum dispenses.

Something has to give.

Spin the winch the other way, and as the inner drum grows fat with string, it gathers in string faster than the outer drum can dispense it. Again, something has to give.

The formula for arc length is s = r theta. Theta is the angle through which the drum turns, and it is the same for both inner and outer drums. The effective radius, r, is a function of how many layers of string have been wound up on top of each other.

Moreover, as r gets larger on one drum it simultaneously gets smaller on the other drum. This means that for a given angular displacement, the arc length S, which is the amount of string dispensed or taken up, is going to be different for the two drums. The difference is not big, but it is big enough that a spring is needed to compensate for it.

If the drums are wide enough that the string never “piles up”, or layers on top of itself, then no elastic is needed. But on a common RC winch drum, it will in fact pile-up. An inelastic line would pop, so we use springs, rubber bands, stretchy winch line, spring loaded idlers, whatever.

Michael

28

Usually, both drums have the same diameter, so there’s just an upper or lower drum. One pays out line, while the other takes it up. And since there are only a few turns of line (4 or 5) around the drum, effective diameter does not come into play. The only thing left is to just put a little tension on the line to keep it from sagging and/or getting fouled.

Why do you think they are of different diameters?

29

Michael, you have nailed it mate.:king:

Yours is the best technical description I have ever read of the challenge of constant tension to prevent lost loops on an endless system.:tophat:

Keep watching Michael, we need your brain here to fathom other technical quandries.:disguise:

Cheers,:cat:

30

Yeah, that will work- until the winchline stretches. Then you’ll need to tighten it up again. The elastic takes care of constantly tightening, and puts tension on the line and around the winch.

31

That may be true, but do you not maintain you boat? I slacken the bowsie of when not sailing, and set it each race day, along with all other checks to ensure a trouble free day. The only negative with this system is if you have an under deck line with limited accesability

32

Good point. Having BOTH the bowsie and the elastic allows you to release all tension on the sheet line when you’re not needing it, and the elastic puts tension in when sailing.

33

Having bowsie and elastic is like wearing belt and braces. The bowsie will keep tension fine on its own. Also, there is no extra boom movement under high winds, the elastic does have extra stretch through varying conditions

34

For two years now I have been using a spring loaded retractable device for my security card at work, last night I tried it out on my boat and it worked great. If it has work for my security card 5 days a week x 30 times a day etc. and it has not worn out yet I think it will last on the boat. Now all I have to do is fasten it to the deck. It is only 1" in dia and made from plastic, does not weight that much. What do you think. I could get a picture if you do not know what I am talking about?

35

Please do post a photo, preferably as installed on the boat. Sounds reliable and interesting. mcg

36

Available at any office supply store, they run about $1-$2 (US) each.

Look like this:

37

Dick that is it. I think it should work good. I have only attached with double sided tape right now but I think I will CA it to the deck, unless there are any other Ideas. ( you can some times get them for free at home shows or trade shows) I keep my eyes open you never know what you will find in the weirdest places.

38

Depending on tension - might want to think Velcro as the thin line does break and it will be easier to remove the spring rewind if fastened with Velcro - rather than CA glue.

Look for “commercial” grade of Velcro - it is much stronger and comes with bigger, heavier weight loops and hooks. You “might” find it in fabric stores - if not, try the canvas/tent/awning places, or maybe outdoor fitters.

39

I have been using my work badge holder/spring for the past 1.5 seasons. It works great. It is very linear and low force. No loop, and if the winch gets fouled, let it all the way out, pulled it all the way in, and its good to go!

My only concern is that I dont think that the spring steel in side has good properties when it comes to corrosion due to salt.

I would try to take pictures, but someone else has the boat. on the first IOM I installed it in, I built a mounting bracket to clip the device onto. . . . after a while, it became apparent that all one needs to do is to drill a hole through the hull and let the spring tension hold it in place. My later boats do not have the mounting bracket, just the hole, and it works great!

-Todd

40

Here are some retracts manufactured with an adhesive flat for surface mounting.

http://www.lanyardsupply.com/lanyards/badge-reel/display/display-retractable-reels-14.htm