laser cunningham

I'm sure there are photos, but I couldn't resist the opportunity to dust of my ASCII-art skills.

The short answer is a 2:1 purchase through the Cunningham eye on the sail, connected to a 5:1 purchase between two double blocks. The diagram doesn't show it, but the dead-end of the 2:1 line is often tied to a becket on the lower double block.

Code:
   2:1
 Through
  Clew
 Grommet
    ^
    |
 ---+----  Double block w/ becket
 O   O  |
| | | | |
| | | | |
| | | | | 5:1 cascade
| | | | |
| | | | |
|  O   O
| ---+---  Double block
|    |
|  Vang
|
|
O----------> cleat
Cheers,

Geoff S.
 
Thanks for the drawing Jeff. You just confirmed that I bought the right stuff for my cunningham. I did not go with the upgrade kit, but instead opted to piece together my own cunningham, outhaul upgrade using the Harken micro blocks, (400 series). Seemed to me that most of the upgrade kits available use larger blocks. almost too big?
 
I think you're right, a number of the kits use the Harken Micros (200 series). The 16mm Air-Blocks (400 series) are smaller and have a higher load-rating, but maybe have higher friction for the larger lines one might want to have running to the cleats.

FWIW, I'm using planning to use the larger 200-series blocks everywhere I'm running the 5/32" Swiftcord that will end up in my hand, and 16mm Airblocks for everything else (where I'm running 1/8" vectran). The only exception is I'm planning to use the 16mm blocks on the deck-fitting to turn the lines to the cleats. I understand keeping the lines low on the deck helps with cleating them eaisly.

There are lots of non-Harken blocks out there, too (the Ronstan Series 20, in particular). There are drLaser articles with more details than (almost) anyone could ever want:
... http://www.drlaser.org/NEWRIG-parts.html
... http://www.drlaser.org/NEWRIG-kits.html
... http://www.drlaser.org/NEWRIG-sys.html

Cheers,

Geoff S.
145234

P.S. "Geoff", "Jeff", no problem. They're both better than alot of things I've been called... ;-)
 
james17 said:
10:1! is that really neccessary? thats a big purchase!

Yeah, most people seem to agree. I'm personally running 8:1 (double-block on top, single with becket on the bottom) and I don't have much trouble pulling on the cunningham.

Cheers,

Geoff S.
 
surely a 10:1 cunningham would stretch the sail! i find that a standard 6:1 is enough to depower in a F5! is 10:1 even legal?
 
Many people argue that to pull the cunningham grommet down by, say, 6 inches, you would need to pull on (6 x 10 = 60 inches =) 5 feet of the control line. Then, that line gets occasionally sucked into the mainsheet ratchet block if not maintained continuously.

Another consideration is the extra weight added by all that extra line on the 5:1 cascade part -- especially if it is a thicker and/or water absorbant line.

Almost no racer in Istanbul or Athens or UK or down under has a 10:1 for the cunningham. Most use 8:1 or 6:1. In North America, even with its relatively calmer winds, the 10:1 is much more common merely because it is what comes out of the Vanguard package.

> thanks guys by the way i am only 13

Good for you, Keiran! You had also written:
"i say that tom is right because only the nerds go 2 the other part of the site." Big words for a 13 year old, right?

> is 10:1 even legal?

As Geoff's ASCII art shows, the 10:1 has exactly two control lines and 5 turning points (including the grommet, and excluding the deck turning block) and is thus fine in these respects...

EXCEPT that it may viloate the text of Rule 3(e)ii -- as I noted umpteen times before asking for a clarification.

This is a rules issue, so no further comments here.

SG
 
ok sort of on the same topic! does anyone have a diagram of the new 6:1 outhaul? im not sure whether this has been mentioned previously!
 
james17 said:
ok sort of on the same topic! does anyone have a diagram of the new 6:1 outhaul? im not sure whether this has been mentioned previously!
I *think* it would look like this:
Code:
  2:1
Through
 Clew
Grommet
   ^
   |
 --+-  Single block w/ becket
 O  |
| | |
| | |
| | | 3:1 cascade
| | |
| | |
|  O 
| -+-  Single block
|  |
| Vang
|
|
O----------> cleat

On advantage of an odd-numbered lower purchase (3:1, 5:1) is that you can use a becket on the lower block to dead-end the 2:1 purchase through the clew-eye (legality discussion aside).

Cheers,

Geoff S.
 
49208 said:
Geoff did diagram the outhaul
The view is from the top.
Yeah, but only by accident...

As I understand it, the big question about the 6:1 outhaul is the location of the single block that's part of the purchase: attached at the gooseneck, or atached to outhaul clam-cleat on the boom (i.e. is the 3:1 near the front or back end of the boom):

http://laserforum.org/showthread.php?t=1246

Cheers,

Geoff S.
 
yeah thanx alot geoff!
i was just sayin that if it was out haul then wat is one of the connection areas doing called vang!
wasnt too sure where to attach the second block thts all!
 
I believe (as i have maintaned in a post similar to this) that 10:1 downhauls are indeed useless
1) the amount of rope you need
2) the frickton
3) the added weight
4) and finally the added money cost!

the 6:1 system is a more "user friendly and cost efficent" way!
 

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