Do the Nacras use such a reinforcing slug at the center of the tie bar? I didn't find one on the 5.0 I'm restoring.
Thanks
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Hobie 16 (3 formerly)
MacGregor 25 (formerly)
Chrysler Dagger 14 (formerly)
NACRA 5.0 (currently)
High Point, NC
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Nacra 5.0 Tiller Tie Bar
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Posted: Aug 23, 2015 - 01:47 PM
The Hobie 16 tiller tie bar uses a slug about 2" long with a 1/4" hole in it at the center where the hiking stick connects. With a 1/4" hole in the tie bar at the center (the greatest point of stress) the tube strength is compromised and the slug acts to reinforce it.
Do the Nacras use such a reinforcing slug at the center of the tie bar? I didn't find one on the 5.0 I'm restoring.
Thanks
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Hobie 16 (3 formerly)
MacGregor 25 (formerly)
Chrysler Dagger 14 (formerly)
NACRA 5.0 (currently)
High Point, NC
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Posted: Aug 23, 2015 - 10:37 PM
Not that I'm aware of. Neither of my boats have that.
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Dave Bonin
1981 Nacra 5.2 "Lucile"
1986 Nacra 5.7 "Belle"
Winnipeg, Manitoba, Canada
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Posted: Aug 23, 2015 - 11:13 PM
Thanks Dave. Just checking and confirming comments from others welcome.
I've seen Hobie tie bars collapse at the center before when folks have removed the hiking stick yoke (as in the 1/4" bolt that it attaches with). The slug can move in the tie bar tube so if you don't know it's there and to find it before reassembly, no slug, no reinforcement = potential collapse.
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Hobie 16 (3 formerly)
MacGregor 25 (formerly)
Chrysler Dagger 14 (formerly)
NACRA 5.0 (currently)
High Point, NC
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Posted: Aug 24, 2015 - 12:23 AM
I believe the Hobie cross bars are thinner walled tube. I've never worried about that on mine.
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Dave Bonin
1981 Nacra 5.2 "Lucile"
1986 Nacra 5.7 "Belle"
Winnipeg, Manitoba, Canada
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Posted: Aug 24, 2015 - 12:39 AM
The Nacra does not have such an item, nor is it required. I'm not very familiar with the Hobie setup, but I've never heard of a Nacra tube collapsing.
If you do a stress analysis, you realize the 1/4" hole has very little effect. The hole is drilled close to vertical. The stress on the tube,(jamming the hiking stik back, or yanking it forward) wants to deform the tie bar in the horizontal plane.
Lets say you pull hard forward. The force is applied to the tie bar through the connecting bolt. The tie bar wants to deflect forward. However, this means the metal in front of the bolt has to be stretched,(under tension), while the metal behind the bolt would have to compress. The wall thickness of the tube is such that almost nothing moves. The vertical hole does not compromise the integrity of the bar.
Lee, resist the tendency to overthink every piece of that boat. Put it in the water, & drive the snot out of it!
We had a glorious day today. 20 kts,(not obscene), but out of the SSE. At my place this means the house & dock are almost calm, but the fetch is 30 miles, with a shallowing bottom at the entrance to the bay I'm in. The waves stack in steep sets, up to 6 ft at the entrance, while inside the point the kids were skiing, tubing, wakeboarding, & driving the guts out of that poor little SeaDoo.
We took the 5.7 outside the point & drove it up to 20mph into & through stacking seas that washed my wife off the boat, twice.
The least of my worries was that 1/4" hole in the tie bar.
The 5.0 is just as tough. I personally prefer the 5.7, as it rides the rough a bit better, but really, you can beat the p*ss out of that boat without breaking it. It suffers a bit in light wind, but 1 up, or 2 up, when the winds up, you will not get the grin off your face. The H16 & H17 from the island retired,(H16 was reefed) after they splashed it a few times. We repeatedly passed them reaching & broad reaching, with green water coming over the deck, & my wife asking if we could sail slower.
Drive it like you don't have a dime in it!
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Hobie 18 Magnum
Dart 15
Mystere 6.0XL Sold Was a handful solo
Nacra 5.7
Nacra 5.0
Bombardier Invitation (Now officially DEAD)
Various other Dock cluttering WaterCrap
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Posted: Aug 24, 2015 - 01:11 AM
Chris is right. It's very easy to overthink things. Simpler is better on the water! For example Ive tried various trapeze setups with 2 and 3:1 purchase and every time I end up going back to the little black plastic dog bones and a simply can't miss loop.
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Dave Bonin
1981 Nacra 5.2 "Lucile"
1986 Nacra 5.7 "Belle"
Winnipeg, Manitoba, Canada
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