Tuesday, November 15, 2011

Winter Upgrades - Heavy metal

With the boat all naked what with no sails and all I've had a chance to look her over and consider what I'm going to do with her this winter.

Right now I've got 2 deck organizers on the port side that allow me to run 6 lines back to the cockpit. Really they can handle 4 lines because the end two sheeves (turning blocks) lost their ball bearings when I installed them.
Currently I run the main halyard, boom vang and outhaul through them and to a clutch, the clutch is pictured in a previous post - it is the 3 line version of this.

Last week I ordered a new 3 line clutch, same as I have on my port side. I'm going to install it on the starboard side.
I also picked up a set of genoa track car's  like the ones pictured to the right. Call me silly by I like Garhauer's stainless steel line, it's heavy, but it's tough. These cars allow you to pull the genoa car forward so you can adjust the sail's clew without leaving the cockpit. Without cars you have to pull a spring loaded pin to disengage the car, then shove it against the pressure of the wind.
Note the car has a fiddle (flat) double block and a double stacked block with a end termination separate. The double stack/end terminal unit goes all the way forward on the track and gets secured there (the screw on the end). The control line leads from the terminal end to the big block on the fiddle, back to the double on the bottom, then back to the small block on the fiddle, back to the terminal block on top, then back to one of these at the rear of the track, and within reach in the cockpit:

 To move the car you simply pull the line which allows the car to slide forward (it's riding on ball bearings). The 5:1 blocks (the way the lines run fore and back around the blocks (land lubbers call them pulley's) mean that it takes 1/5 the effort minus friction loss to move the car. That's good because sometimes the wind puts so much pressure on the sails you can not do it without help.
The car will slide to the stern under wind power (the genoa is pulling it up and forward all the time, the control line is holding it still).

You adjust these cars to allow the clew (back, bottom) of the genoa (forward sail) to move forward / aft and in and out.
Let's see if I can describe it for both sailors and non-sailors. When sailing upwind (into the wind) you want the genoa  to be back and tight to the center line of the boat, that allows it to point into the wind and causes the wind to channel better over the back of the main sail. That channeling creates what a sailor calls the "slot".
To effect that one would put the car further aft, and where it goes and works best depends on wind speed and whether or not you have the genoa reefed (made smaller because of high winds). My first 'reef point' is to furl my 150% genoa to 100%.

- a brief side note, 100% refers to the area of the fore triangle; a triagngle that is sided by the deck (foot of the sail), the mast and the luff (forward edge) of the sail. A 150% genoa, like mine infers that the clew of the sail goes back another 50% past the mast. My foot is 14 feet (tack of the jib to the mast) so a 150% would be 7 feet longer, I have a furling genoa, it rolls around the forward edge (on a aluminum foil) to store it, and to make it smaller in high wind...end note

What that means is that in order to have the clew (back, bottom) of the genoa held at the same angle relative to the wind when I furl the sail to the first reef I need to move the car 7 feet forward of where it was at 150%. That's a lot of push pin pulling and car sliding while standing bent over a track in 20 knots of wind. Hence I'm adding the cars. It's not just performance, it's safety.

Ah, but there is more.
When going downwind and even on a reach (side ways to the wind) you want the clew of the genoa to be able to curve out ward away from the center line of the boat. Consider that the main sail is going to also go away from center line when sailing at 90 degrees off the wind, would you want your genoa to curve inward and have the wind from it back winding the main sail? So you move the car forward to prevent that cupping force.
Downwind you want that big honking sail out so it can catch air like a kite, you move the car all the way forward so you aren't closing the sail up like a laundry bag.

Still more, because gosh if there wasn't anyone could do it (well actually anyone can do it)...
There are times when you want to pull the car more forward than normal. Pulling the car forward when going upwind puts more 'bag' in the sail, making it rounder and fuller. A rounder sail means you can't point into the wind as well, but gives more "power" i.e. pulling force, something you need in heavy chop/waves, or in truly light and fluky wind - it's better to move a 50 degrees than to not move at 40 degrees off the wind.

Next up, we'll talk Cunningham's, Out hauls and what all that other heavy metal is for.

1 comment:

  1. Most excellent post Chuck! Not only showing off your soon to be added shuny bits but a nice explaination of where and why.

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