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PostPosted: Fri Sep 01, 2006 12:15 am 
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Hobie Approved Guru

Joined: Sat Nov 12, 2005 10:46 pm
Posts: 2388
Location: Escondido
After noting how (comparatively) well the Revolution sails, especially upwind, I decided to experiment with my Adventure.

I came to the conclusion that, because Hobie sails are loose footed, the aft sheeting position is critical to sail performance. Too far aft and the sail develops too much twist; too far forward and the sail develops too much camber along the foot. On a conventional sail, these functions (and others) are performed with a boom.

The stern pad eye is about 14" further aft of the sail on the Adventure than the Revo, so moving the sheeting block forward by this amount seemed like a good place to start.

I accomplished this by making a harness as shown, allowing extra length for adjustments. The block is free to side to side across the bridle (when slackened), but the amount of forward travel is limited by the aft line, passing through the pad eye before ending up in the cockpit where it can be remotely adjusted. Thus, the block's location is fully adjustable without drilling any additional holes.
Image

Here's a close up. I'm using a Ronstan swivel block with all three lines passing through the attached shackle. In its present position all lines are taut and the block is located about 15" forward of the pad eye or about 8' 0" aft of the c/l of the mast. When taut, almost no movement of the block can occur.
Image

The next pic shows the mainsheet passing through its new position.
Image

Finally, here's where I control the harness. The harness line passes through the Hobie screw-in pad eye (which is shared by a forward swivel block for the mainsheet) and back to an existing jamb (or clam) cleat. I can also release the bridle to gain access to the rear hatch.
Image

The upwind performance improvement was substantial! Having tried a couple of adjustments, so far, the position shown is the best I've found in 10 - 15 kt wind. There is less twist along the leach and consequently, a flatter sail, providing more drive and less tendency to capsize! 8)

Note: I did a second (and final) update on 4-48-07 (should be on page 2).


Last edited by Roadrunner on Sat Apr 28, 2007 9:30 pm, edited 1 time in total.

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PostPosted: Fri Sep 01, 2006 5:31 am 
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Location: new york,ny
Hey Roadrunner!

Another great mod beautifully illustrated with pix! And without drilling any more holes. Very clever! Maybe his mod will be adaptable to the Adventure Island, which also has a loose footed sail.

I think I understand everything except for this line in your post: "I'm using a Rostan swivel block with all three line passing though the attached shackle." In the pix, I see only two lines. One for the tention ajustment and a second for the traveler line. Is the third line the main sheet that is not shown?

Punch


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PostPosted: Fri Sep 01, 2006 9:25 am 
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Location: Escondido
Hi Punch,

You're absolutely right! There are only two lines, just as you described. Sharp eye!

The small Hobie sail was introduced before the Adventure and was never designed for it, so this was a fix begging to happen!

But on the Island, the sail was built for it, so you know the rigging is much better tuned -- especially if they've had it up to planing speed!

As our sailing guru, it'll be fun to see what mods you make on your AI. I can already see a bowsprit and jib in your future! Maybe you can squeeze a Mizzen on too? :lol:


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PostPosted: Sat Sep 02, 2006 4:25 am 
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Location: Canberra, Australia
What a fantastic mod!! Now that spring has finally arrived down here Im off to the sailing shop tomorrow to get the gear to make this mod.

A question though...why is the line from the block back to the rear padeye running back up to the cockpit and not just tied off at the padeye. What does this achieve?

Thanks...great work!! :D


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PostPosted: Sat Sep 02, 2006 1:47 pm 
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Location: Escondido
Hi Booligal,

Thanks. When I was first experimenting, I wanted the ability to quickly adjust the block position from the cockpit while sailing (instant feedback). I'm not quite finished "fine tuning" . So far, I've only had about an hour test time, in fairly brisk winds, but am very happy with its present position.

The cockpit rigging also allows an instant release for hatch access. I can replace this later with snap hooks.

The jamb cleat was already in place for the mainsheet, so I didn't add anything. BTW, the block rigging line is called 550 (parachute) cord -- small, inexpensive and very strong (550 pound test).

Let me know how yours turns out! 8)


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PostPosted: Mon Sep 04, 2006 12:45 am 
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Update: I moved the block forward about 1 inch today in heavy winds (15 to 20 gusting to 25). Got some nice speeds (sail only: 6.6 mph max (GPS)). Here are a couple of pics of the rig in operation and a couple showing sail shape. The sail seems to be pulling well!.
Image
Image
Image
Image
It seems that the optimal block position changes with wind speed, especially since the mast bends so easily (this is very true for jibs, which are also loose footed). So the cockpit adjustment may become a permanent part of the rigging. 8)

Note, there is a second and final update on pg. 2 posted 4-28-07.


Last edited by Roadrunner on Sat Apr 28, 2007 9:33 pm, edited 1 time in total.

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 Post subject: Hey Roadie
PostPosted: Mon Sep 04, 2006 8:39 am 
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Joined: Thu Jul 27, 2006 4:50 pm
Posts: 461
Location: sacramento california
Howz it dune Roadrunner..
:wink:


Last edited by kepnutz on Tue Sep 16, 2008 9:10 pm, edited 1 time in total.

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PostPosted: Tue Sep 05, 2006 6:39 am 
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Joined: Thu Feb 16, 2006 5:12 am
Posts: 33
Location: Louisville, Ky
roadrunner, how did you get photos right in your post, I cant see how to do that from the reply window?


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PostPosted: Tue Sep 05, 2006 8:35 am 
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Location: Escondido
kepnutz wrote:
So hows that new rigging working out? Do you think your new system was faster than just rigging through the rear pad eye. Did it point higher ? Heel more? Stall the rudder?
Did you sail it rigged both ways in the same conditions to compare performance? What adjustments would you make to the rigging under what conditions..forward for lighter wind ..back for heavier winds..etc..etc

I would say it does not point any higher, but carries more power into the wind close hauled. More control over heel because the upper leach is more controllable, sail can be made flatter (may have otherwise capsized in these conditions!). No difference in rudder control ( but never had any problems w/ larger rudder).

My initial thought was to move the block aft in heavier winds, but , because the mast bends so easily, I'm thinking the reverse is true. I ended up shifting forward slightly from the first position. The guideline is, if the upper half of your sail is luffing first, move the block forward more; if the lower half luffs first, move the block back. Problem is, it's hard to spot the lower luff because the clear plastic window is stiffer than the upper sail material!

It's a definite improvement, but I I need to see it in more varying conditions to see if I can make any further improvements! 8)

gregw wrote:
roadrunner, how did you get photos right in your post, I cant see how to do that from the reply window?

You can't, directly. The picture must be "hosted". There are several hosting sites. I use ImageShack. http://www.imageshack.us/ .

--click on the site

--click browse

--when you find your picture, click open

--next screen, check resize image?; select 320 x 240. This gives you the same size you see here. The bigger you make it, the longer it takes to open the posting!

--click host it!

--next screen, select either thumbnail for forums (1) or hotlink for forums (1) (what I used here). Right click copy.

--Go to your forum post; right click paste.

That's it. Sounds cumbersome, but once you do it a few times it takes less than 30 seconds. I generally do the hosting in a separate window while I'm writing. It works great -- looking forward to your picture(s)! :D


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PostPosted: Tue Sep 05, 2006 4:38 pm 
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Joined: Thu Feb 16, 2006 5:12 am
Posts: 33
Location: Louisville, Ky
To follow-up on some of Roadrunners modifications, I tried some of my own on the same theme. Image With the addition of the Hobie Ama, my cart wheels needed to go to the back and after seeing roadrunner's mods I tried this. It also allows me to manually move the anchor point left and right. Image
The other modification was to add a thin (1/4") fiberglass rod to the foot of the Hobie sail. This has really helped keep the shape of the sail, especially in downwind sailing. The sail can still roll-up by bringing the foot up parallel to the luff and then rolling from the middle. I simply cut (actually melted with a soldering iron) a slit into the foot's sewn pocket and slid it in. I don't have a good picture but can add one if needed.


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PostPosted: Tue Sep 05, 2006 10:54 pm 
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That fiberglass rod sounds like a great idea. Where did you pick up the rod? It's a little like a boom and a batten -- perhaps a boombat?

Keep us posted on the results of your modified fairlead! Nice pics by the way. 8)


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PostPosted: Wed Sep 06, 2006 3:36 am 
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"Boombat" I like it!
I just found that rod floating around my garage, don't know where I found it. I think it was designed to stick in the ground by a driveway to mark it's location, it has reflective tape around the top end and pointed at the other?
My next experiment will be with a jib sail, I described it here. http://www.hobiecat.com/community/viewt ... f42990e873

More photos to come, thanks Roadrunner for the lesson.


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PostPosted: Sun Sep 24, 2006 8:37 pm 
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As I develop more feel for the boat and sail, I've been able to become better at shifting my weight. Yesterday I got up to 6.7 and today the GPS gave me 6.8 on a beam reach.

The first sail area today is where the wind surfers usually go -- usually the best wind on the lake and relatively steady. Naturally they're MUCH faster -- but they keep falling over and need to come out frequently to rest! They also appear to lack the means to sail to and from the launch zone, relying on boat transportation.

Later I pedaled/sailed to another wind area where it's usually gustier, but with less chop. When I finished, the GPS had recorded 7.9 MPH! I didn't do anything fancy along the route that was even close, but since I didn't reset the GPS, there is no way I could verify that the speed was actually earned by sailing alone, so I'll have to stick with 6.8MPH for now.

I'm pretty happy with the latest position of the sheet block just in front of the rear hatch/aft edge of the cargo well. I also arranged the traveler so the block pretty much stays on center line.


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PostPosted: Sun Sep 24, 2006 10:28 pm 
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Actually, the speed figures are of no practical significance. Considering that most sailing kayaks are probably the next slowest things to algae, sailing the Hobie has more value as a modest boost to pedaling.

Realistically, anything in the 3's is a nice sail. Getting into the 4's takes a bit of wind. Normally, seeing anything in the 5's is brief and with a good wind. Beyond that, it's a momentary thing, achieved with some discomfort, lots of wetness and a bit of luck, for the sake of nothing more than the challenge.

So If I "achieve" some momentary speed, it has no bearing on the average speed or getting any place except wherever the wind dictates! Still, I'm shooting for 7!


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 Post subject: Hey Ya Doin Roadie
PostPosted: Mon Sep 25, 2006 4:06 pm 
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Joined: Thu Jul 27, 2006 4:50 pm
Posts: 461
Location: sacramento california
"
:P :lol:


Last edited by kepnutz on Tue Sep 16, 2008 9:10 pm, edited 1 time in total.

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