rope/line "lock" vs a clutch?

centerline

centerline

.
Mar 20, 2012
3,983
Cal 34-III, MacGregor 25 Salem, Oregon
does anyone know of a device that operates similar to a rope clutch that will actually lock the line from being moved thru it in either direction?...

a clutch, with the handle locked down, the line can still be pulled thru the "clutch", adding tension to the working part of the line...

I want something strong, yet simple to release, like a clutch that will positively hold the line from moving no matter which way its pulled...
 
Scott T-Bird

Scott T-Bird

.
Oct 26, 2008
6,081
Catalina 320 Barnegat, NJ
I guess my question is, why a jammer instead of a cleat or a clutch. What would be an application where a jammer is preferred and why?
 
Jackdaw

Jackdaw

.
Nov 8, 2010
11,386
Beneteau First 36.7 & 260 Minneapolis MN & Bayfield WI
Scott T-Bird said:
I guess my question is, why a jammer instead of a cleat or a clutch. What would be an application where a jammer is preferred and why?
Click to expand
Mostly a big-boat issue. Jammers have a MUCH more secure grip on the line. They slip much less (if at all) then a clutch does. On the 367 our XTS clutches slip 0.5-1.0 inch on tight main and jib halyards. And this is after a re-build.
 
centerline

centerline

.
Mar 20, 2012
3,983
Cal 34-III, MacGregor 25 Salem, Oregon
Scott T-Bird said:
What would be the application for a jammer?
Click to expand
my traveler is installed on the bridgedeck and it currently has jam cleats to hold the adjusting lines tight.
on either side of the car, port and strbrd, there is a 4 part tackle. the line is anchored at the becket, runs thru the sheaves, then around a turning block at the outboard end of the track, and then back to the jam cleats at the center of the bridgedeck.... the same routing on both sides, with the tails of the lines laying in the cockpit floor

what I propose to do is install a "jammer" in place of the two jam cleats, and then run the line as an endless loop from one side of the car to the other side.... the adjusting line would travel back and forth thru the unlocked jammer, until I lock it down where i want the car to remain.

this would clean up the mess a little and at the very least, be more user friendly when adjusting the traveler... just unlock the lever, grab the mainsheet just above the car and pull/push the car to position and lock it down.


OR.... let me know why it wouldnt work as I think it should:D
 
Joe

Joe

.
Jun 1, 2004
8,007
Catalina 27 Mission Bay, San Diego
Centerline... an issue may be the friction of the line running though the jammer, because it is a "captive line cleat"... whereas the jam cleats are the open vee "non captive" type that allow you to simply snap the line of when you adjust the car....and you have to move to engage, disengage.

I certainly think it's worth a try though. I have used an endless traveler line for years and find it much more convenient that two separate ones. Easier to find and control. I would go ahead and convert to the endless line... but move the cleats to the side of the coaming where you can sit on one side of the cockpit and snap the line out of the cleat on the opposite side. The problem with the jammer in the middle is that ..it's in the middle... and you have to move to release it.
 
Ron20324

Ron20324

.
Jan 22, 2008
8,050
Beneteau 323 Annapolis MD
Jackdaw said:
You want a jammer. ...]
Click to expand
The link was British, and they used the word "jammers". IIRC my 92 B235 had those as OEM line stoppers. They will yield in one diection, but the OP wants NO yield in either direction. I replaced them with real line stoppers/clutches and took the old ones to Bacons.
 
Brian S

Brian S

.
Nov 9, 2012
2,500
Oday 192 Lake Nockamixon
I should think you'd want a cam cleat on traveller control lines. You could still do a continuous line, but you really only ever want to keep the traveller from falling down leeward. Cam cleats with the captive "loop" over the top would be much quicker and easier to work with than a lever actuated jammer. Remember, you ought to be playing the traveller for puffs and such.

If I'm reading Centerline's plans correctly. Some travelers have cam cleats at the ends of the track, some Harkens I've seen have the cleats on the car.
 
Scott T-Bird

Scott T-Bird

.
Oct 26, 2008
6,081
Catalina 320 Barnegat, NJ
That sounds creative, but ....

I'm skeptical. Moving the traveler car by hand under load is more difficult without the purchase provided by the blocks that you already have installed. I think that your endless loop would have to be pulled taught from one side of the track to the other led thru the jammer in the center to make the jammer function as intended. This would add friction, making it more difficult to move the traveler windward under load.

But despite the friction, you will still have to hold the car in position while you set the jammer, lest the car slides to leeward if you let it go ... a two handed operation. It sounds like it might be adding complexity and making it necessary for you or somebody to be in the immediate vicinity of the bridge deck to work the traveler rather than simplifying the operation. Plus, levers seem more difficult to release under load than a cleat.
 
thinwater

thinwater

.
Mar 26, 2011
3,414
Corsair F-24 MK I Deale, MD
There are many reason why you would NOT want to do that:

  • Probably will not function in light air if there is enough tension to function in heavy air. Too much friction.
  • Will need to use non-stretch line, which is not a good idea on travelers (some shock absorption is needed).
  • More difficult to pre-set post-tack traveler position.
  • Harder to control through jibe.
While a continuous traveler line is good (have that on both my current and last boat) you really want to keep separate cam cleats for each tack. Lose the jam cleats.
 
Scott T-Bird

Scott T-Bird

.
Oct 26, 2008
6,081
Catalina 320 Barnegat, NJ
Yes, cam cleats on both sides are the best bet. Position them so you can work both lines simultaneously from behind the helm. My cam cleats are combined with the blocks on a standard 3:1 purchase. The best place to work the traveler is from behind the helm. All it takes is a flick of the wrists to work both lines simultaneously. I reset the traveler either just before or after tacking when single handing. Just before is usually more efficient because of the time it takes to set the genoa. Its actually much easier to set the traveler from behind the helm than it is when sitting right next to the bridge deck.
 
centerline

centerline

.
Mar 20, 2012
3,983
Cal 34-III, MacGregor 25 Salem, Oregon
Scott T-Bird said:
I'm skeptical. Moving the traveler car by hand under load is more difficult without the purchase provided by the blocks that you already have installed. I think that your endless loop would have to be pulled taught from one side of the track to the other led thru the jammer in the center to make the jammer function as intended. This would add friction, making it more difficult to move the traveler windward under load.
Click to expand
as im not a racer, and if i have to adjust the travelor at all, there will be someone near it anyway to operate the line in rhe jam cleats....

But... this "quote" from Scott, (thank you), is what i overlooked and is the only completely sound and valid reason for not trying it...

with the endless line captive in the jammer, it effectivly makes the multiple part purchase of he blocks unusable... because i am not able to haul on the tail of the line if there isnt one to haul on.
Just grabbing the traveler to slide it to where i want it so i can lock it down, is only providing a 1-1 purchase... defeating the purpose of the installed tackle...
 
You must log in or register to reply here.

Top Bottom