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PostPosted: Wed Jul 09, 2014 9:38 pm 
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I have been stalking this forum, and watching the threads for a long time. I have always wanted to improve the low wind/pointing ability of my TI and bounced back and forth between either a jib project or a collapsible wingsail... I guess there isn't a reason you couldn't do both, but I decided today to start on a jib.

Here is day 1 progress on the Adjustable/Removable Bowsprit. I didn't want to punch any holes in the boat, so I used existing mount points. The Bowsprit is just a 3/4 x 1/8 aluminum square tube that slides into a 1" x 1/16" square tube.

The bowsprit itself is the only part that may need to be stronger that I can see... if it does I will simply swap it for 3/4 Stainless.

Sorry for the pictures being dark, quit after dark and took them with an iPhone and flashlight.

Oh and that is a bike rack mounted to the trailer.

Image

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PostPosted: Thu Jul 10, 2014 5:42 am 
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Location: Sarasota,Key West FL
Nice looking setup, if I ever have to redo mine I will likely make it telescoping, that makes storing in the garage way easier. If you need more strength on the inner sq tube you might be able to slip a fiberglass rod into the sq tube ( nice and light, and corrosion resistant). Doesn't need to be a perfect fit in the tube, basically the rod would still let the tube bend but would prevent it from buckling.
The main reason I added a bowsprit to mine was to angle the foresails so they create some lift to the bow. With your setup you will be able to control how much lift you want to dial in.
I found from experience a jib over 30 sq ft can create too much heeling moment (the force trying to tip you over) unless you have the ability to furl it in some in higher winds.
Having a huge spinnaker way out front doesn't seem to effect steering too bad (mostly because a spin is only used downwind). If you have a really big jib mounted way out there, you may overwhelm the rudder on a reach in higher winds.
One thing about my setup is I tend to never try to sail in a beam reach (wind 90 degrees to the bow), as it's probably the worst point of sail on my boat. I get the best performance on a close reach with the wind coming straight at me from 15 to 45 degrees off the wind.
You won't see a big gain in top speed (maybe 1-2mph) but you will be able to sail much closer to the wind, and still make headway in very light winds.
When on a downwind by setting the sails in a batwing configuration you can improve the downwind performance of the boat (just having that ability makes the mod worth the effort).
One added benefit of the jib is it helps organize the airflow over the mainsail, increasing the mainsails efficiency.
Hope this helps
Bob


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PostPosted: Thu Jul 10, 2014 6:21 am 
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I read that about the lift, and that was one reason I did it, the other is my trailer is long since built and my tailgate won't open if the boat is any longer. :)

My jib is pretty close to 30sqft, plus I plan on a furler for it.

The debate in my plan is if I need an aft stay off the topper


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PostPosted: Thu Jul 10, 2014 7:25 am 
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Location: Sarasota,Key West FL
My rear stay doesn't do a lot beside help keep the mast topper from rotating with just a jib. Actually on a reach and upwind it's slack because the mast bends back. However as soon as you get into a downwind it does it's job by preventing that little stud at the bottom of the hull from sheering off.
Think about it, on a downwind your sail control line is usually loose, all the forward force is on that little stud, to make matters worse the force acts like a lever multiplying the force x 17 times ( literally you could easily lift your car up with that much force). If you don't believe me just open your sail completely in your drive with the mast up. A quick snap jerk on the control line with the sail already tight will snap that stud in a heartbeat. Same applies with forward force on a downwind but you don't have your clew line to catch it on a downwind because it's already loose, that's why you need a stay.
Hope this helps
Bob


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PostPosted: Thu Jul 10, 2014 7:35 am 
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Joined: Sat Nov 05, 2011 1:58 am
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Location: Forster, NSW, Australia
Bob, I seem to recall a conversation involving placing a solid block between the mast base and the Miragedrive slot to counteract backwards forces on the mast base, and a ratchet strap around the mast base and the rear of the Miragedrive to counteract forwards forces on the mast base. These two, together with the existing V brace, would seem to fully secure the mast base andminimise the prospect of the pin shearing.

_________________
Tony Stott
2012 Tandem Island "SIC EM"
www.scenefromabove.com.au


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PostPosted: Thu Jul 10, 2014 7:43 am 
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I know what you are saying, but I'm not sure I agree with the math/logic.

On a reach you will have at least as much force on the sail holder at the bottom. Not only will the apparent wind be blowing much harder than on a downwind, all the force is actually 90° to the boat with almost all your force on the mast.

That said, I never thought about needing to keep the topper aligned, that may be enough to convince me to add the rear stay. :D


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PostPosted: Thu Jul 10, 2014 8:15 am 
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Location: Sarasota,Key West FL
I have my stay line there if I'm gonna need it but on light days I don't always connect it. I don't worry about the side to side forces so much, the v brace system is very strong side to side.
Bob


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PostPosted: Fri Jul 11, 2014 8:26 pm 
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I see what you mean about the ax handles. Just got one for my topper. Will hopefully have it up this weekend.


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PostPosted: Sat Jul 12, 2014 5:20 am 
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Location: Sarasota,Key West FL
Those axe handles are awesome, I was chief engineer at the company that first developed them, and designed the product and manufacturing process for them. The guys in the factory would place the ends on 2x4's then jump up and down on them like on a trampoline and compete against each other (true story). I had a couple still laying around in my garage (from 20 yrs ago (lol)) and used them for both my bow sprit and my mast topper. I pick up my TI all the time by the tip of the bowsprit, and to test out my mast topper I put the mast in to the boat and strung a rope loop to each end then sat on it (like a rope swing), it supported all my weight. I thought about making a trap harness setup like on a Hobie cat but found the mast is too flexible (never thought about how I would actually use it though, again the trap harness was not one of my better ideas (lol)). It's sitting in the garage along side my 3 sets of hydrofoils, my pulley system for operating both mirage drives from the front seat, and the rig to operate the mirage drives with a cordless drill, all cool ideas but not ready for prime time. (Lol)
I just like to tinker with stuff.
Bob


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PostPosted: Sun Jul 13, 2014 11:03 am 
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Location: Sarasota,Key West FL
tonystott :
Tony you are correct I do have a small piece of 1/8 x 2 by around 8-9 inches long aluminum that I cut to fit between the back of the mast holder at the bottom and the front of the mirage drive. I then made a clay dam around the area and filled the area with epoxy (maybe 3/8" to 1/2 " deep). I did that a couple yrs ago and it's still going strong. I have not sheared a single mast stud since putting that in.
Here is a video of the aluminum piece and the clay dam:
[youtube]https://www.youtube.com/watch?v=jU4paaX3lzU[/youtube]
https://www.youtube.com/watch?v=jU4paaX3lzU
I ended up taking that strap out because it got all moldy.

But then again I also tend to stay home anymore if the winds are over 8 mph because of my bad back ( I broke it many years ago) the rough chop and waves just kill me anymore so I tend to only try to go out on flat water with no to low winds anymore, ( the main reason my boat is rigged as it is). However we are planning to go down to our Key West place next week for a while (mini Lobster season is the end of July) and I will definitely have my giant spinnaker mounted on the boat to take advantage of the great trade winds in Key West. When the winds are low (<10mph) the boat is already faster than the wind so I can't use the spinnaker at all so up in Sarasota I just leave the spin at home in the garage. You physically can't sail faster than the wind speed with a spinnaker, However with the spinnaker I can typically sail 1 to 1 with the wind up to around 22mph winds, anything above that is down right dangerous, and I shouldn't put the spinnaker out.
Bob


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PostPosted: Sun Jul 13, 2014 5:55 pm 
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Still need cleats and pullies, but I was able to trailer sail it today!

I think the jib and bowsprit are in about the correct positions.

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Ended up making some tweeks to the topper.

1. Used the normal 1.5" drain tube, but grabbed the one that gets a bit wider and then has threads. Then cut the threads off. I like the force not being on the sharp end, but the rounded part of the tube.

2. I wrapped the mast in 1 layer of rolled roofing, then 2 layers of electrical tape. That way it protects the mast more, and also has a lot less slop.

I did the same with the 1" pvc out the top... still not sure. on this though. I may need to make some mods... a lot of friction to furl the main.

The topper then has a fiberglass rod from an ax handle running through the 1" pvc, near perfect fit. I then added 1 bolt through each cap, and one through the T to keep it all in place.


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PostPosted: Fri Jul 25, 2014 8:30 pm 
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Well the first trials are complete. The weather steer wasn't as bad as I had feared, but I need to add the PVC to the front of the jib to hold the jib's shape.

In low wind the improvements were incredible. I could point WAY better than before... not to mention I could actually move. It also generated quite a bit of lift on the front of the boat and kept the ride much dryer.

All that is left if finishing the Furler, hopefully over the weekend I can finish that up!

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PostPosted: Fri Jul 25, 2014 8:34 pm 
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Oh, and Fusion, you were right... Rear stay was a good idea!


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