Downhaul Rigging

Technical discussion of ARC products
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RobLyman
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Posts: 11
Joined: November 28th, 2003, 1:29 pm
Boat Make/Model: RC-27, ARC-22
Location: Jacksonville, FL

Downhaul Rigging

Post by RobLyman »

This is specific to my new-to-me ARC-22, but I figured it might be useful to other platforms as well.

My ARC-22 mast was rigged as in the 1st picture. I am not sure how the downhaul is supposed to be rigged.
Downhaul.jpg
My RC-27 had an extra set of cleats on the mast, which made it easy to rig a cascade to get 16:1 (see below)
16to1Downhaul.jpg
What is the standard way to rig the ARC-22? The class rules say 12:1 max.
(Hoping to get a little more activity here :D )
RC-27
ARC-22
Hobie 18
gahamby
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Joined: July 24th, 2012, 7:02 am
Boat Make/Model: SuperCat 15#315
Location: Falls Church VA 22042

Re: Downhaul Rigging

Post by gahamby »

When I got the new square top main, Tom sent me the drawings I needed to rig the regulation downhaul. Mine is a little less involved than yours. I posted a picture here on the forum.
viewtopic.php?f=3&t=1012
Matt Haberman
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Re: Downhaul Rigging

Post by Matt Haberman »

Hi Robert,
All of the ARC-22's shipped with the standard 6:1 downhaul system & three grommets in the mainsail as illustrated in the link Ghamby shared. The way that you string it is by starting at the exit block / cleat on the starboard side, go up to the middle grommet in the mainsail. Next, you go down to the cheek block on the port side, threading from front to aft. From that block you go back up to the bottom grommet in the mainsail and down to the cheek block on the starboard side, threading from aft to front. Lastly, you go back to the top grommet and down to the exit block / cleat on the port side. When you are down none of the lines should cross on the port side of the mast and on the starboard side you should have only one line crossing the others.

I am not certain about the blocks you showed in your photograph, but it seems to me that you have a lot of extra unnecessary hardware and mechanical advantage. We have found that 6:1 is more than adequate to trim the sail on the 22 and adding additional mechanical advantage only adds weight and complexity. The mast on the 22 is pretty stiff compared to many other boats and as a result the sails typically don't respond significantly to the higher downhaul purchase.
Matt Haberman
Aquarius Sail Inc.
http://www.aquarius-sail.com
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RobLyman
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Posts: 11
Joined: November 28th, 2003, 1:29 pm
Boat Make/Model: RC-27, ARC-22
Location: Jacksonville, FL

Re: Downhaul Rigging

Post by RobLyman »

That is surprising considering even Murrays Hobie 18 downhaul kits are 6:1 and 8:1. I was sure the 22 would have something more powerful. Current standard on an A Class (non foiling),F16 and F18 is 16:1. When the wind pipes up, I can't imagine that a 6:1 system would allow enough downhaul tension to bend the mast and flatten the sail to the point required in 18 kts or more TWS.

I wonder if anyone has added more purchase to their downhaul. It seems like a relatively inexpensive way to update the boat with the ability to gain a 5th gear or overdrive when the wind pipes up. After all, it's not just about surviving heavy air. You want to reduce drag, especially at the top of the sail. A luffing or flapping sail is a slow sail.
RC-27
ARC-22
Hobie 18
Matt Haberman
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Re: Downhaul Rigging

Post by Matt Haberman »

Robert,
Keep in mind on the H18 w/ Comp tip and the A class the masts are quite bendy and the downhaul has a major effect on the sail shape and mast bend. The mast on the 22 is significantly stiffer and as a result, downhaul has a much smaller impact on mast bend and sail shape. If you put a large enough downhaul on to start bending the mast you're headed down the route of a broken mast. There are a few 22 sailors that can attest to that...

To depower in heavy air you move the mainsheet blocks forward on the clew plate, this will flatten almost all the shape out of the mainsail and drastically depower the rig.
Matt Haberman
Aquarius Sail Inc.
http://www.aquarius-sail.com
Kevin Keller
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Joined: September 24th, 2006, 2:56 am
Boat Make/Model: SC-20, ARC22
Location: Honolulu

Re: Downhaul Rigging

Post by Kevin Keller »

I’ve got a setup on my 22 that rigs quick. I’ll take a picture next time I go out.
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