Early Nacra crossbar retention, 2 bolt vs straps, which is better?

Early 80 Nacras had 2 bolts thru the cross bar to hold to hulls, later models had straps over the bars;
So there are 2 vs 4 anchor points respectively. More is usually better. Is the 2 bolt system strong, or best to get a boat with the straps?

Do the through bolt anchors cause more cracks?

Thanks.

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John

Nacra 5.0
CT
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The later boats had a 5-point connection in the front beam. In addition to the straps, a bolt inside the crossbar prevents rotation. I think the fact the straps were used in the later design was done for a good reason to distribute the load. I guess any boat that has survived 40 years deserves respect, but I would favor the newer design.

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Tom
NACRA 5.7 (1984 Sail 181)
Pennsylvania
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Thanks Tom.

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John

Nacra 5.0
CT
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I agree,inserted bolt besides 2 straps each side on my 5.2 before lost to hurricane Sandy I also kept the aluminum bar that ran from front cross bar to rear cross bar. sandy destroyed hulls but "frame"did Not suffer any damage, I duplicated same securing design for my N5.7 when we diassembled front cross bar to install new dolphin striker & bolt below mast- instructive photos available on this site were a Hugh help
I agree,inserted bolt besides 2 straps each side on my 5.2 before lost to hurricane Sandy I also kept the aluminum bar that ran from front cross bar to rear cross bar. sandy destroyed hulls but "frame"did Not suffer any damage, I duplicated same securing design for my N5.7 when we diassembled front cross bar to install new dolphin striker & bolt below mast- instructive photos available on this site were a Hugh help
My 1983 Nacra 5.0 has the 2 bolt setup:

https://www.thebeachcats.com/gallery2/main.php?g2_view=core.DownloadItem&g2_itemId=119449&g2_serialNumber=4

When I got it, it only had one internal beam casting (no boss) at the end of each beam (total 4). I noticed that the hole in the beam was much larger that than the bolt, but didn't know why. Then I learned that there was a second type of internal beam casting with a boss to index the hulls to the proper width and prevent beam rotation:

https://www.thebeachcats.com/gallery2/main.php?g2_view=core.DownloadItem&g2_itemId=119491&g2_serialNumber=4

https://www.thebeachcats.com/gallery2/main.php?g2_view=core.DownloadItem&g2_itemId=119499&g2_serialNumber=4

To bolster the design a bit and correct my boat, I bought (4) additional castings with the boss. I run (1) casting with boss and one casting without boss at the end of each beam. 3-1/2 seasons on the boat so far and no issues. I do periodically check the bolts for proper torque and sometimes find that they are a tad loose. My strongest advice on these bolts is that you can not apply enough anti-seize compound before assembly. It's a SS nut on a SS bolt which a perfect recipe for seizing up and twisting off and you DO NOT want to go there icon_confused

https://www.oreillyauto.c…cant/81343/4610251?pos=1

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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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I thought the early boats were the ones with the straps and the later ones had the bolts. My 18 square is an 82 and has the straps only.
tamumpower1I thought the early boats were the ones with the straps and the later ones had the bolts. My 18 square is an 82 and has the straps only.


Don't have an answer for you on what models and years used each type. A friend in our local club has a 1984 Nacra 5.0 and it has straps??? Go figure...

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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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Hey all! Was going to make a new thread but this seemed like a good place to start!! I just picked up a 70s 18’ Alpha/Hobie cat for a friend. The front crossbar is not really secured and can slide side to side, well it slid too hard and punched through the hull... I can do Fiberglas work and fix it, but my question is how do I prevent this and how is it supposed to be secured?

Can I not attach pics directly to a post?
sailwyomingCan I not attach pics directly to a post?

Yes, you can, go to Site FAQ, on the menu, at the very top of the page.

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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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Hey all! Was going to make a new thread but this seemed like a good place to start!! I just picked up a 70s 18’ Alpha/Hobie cat for a friend. The front crossbar is not really secured and can slide side to side, well it slid too hard and punched through the hull... I can do Fiberglas work and fix it, but my question is how do I prevent this and how is it supposed to be secured?

https://www.thebeachcats.com/gallery2/main.php?g2_view=core.DownloadItem&g2_itemId=130646&g2_serialNumber=4&g2_GALLERYSID=650f3311d7ae9074de4edad2e8e73d1d

I put the zip ties on after to keep the pole from sliding down during transport.
https://www.thebeachcats.com/gallery2/main.php?g2_view=core.DownloadItem&g2_itemId=130651&g2_serialNumber=4&g2_GALLERYSID=d4ba977f7400c014e4ac55ad95d68cfe



https://www.thebeachcats.com/gallery2/main.php?g2_view=core.DownloadItem&g2_itemId=130659&g2_serialNumber=4&g2_GALLERYSID=d585075592ce6219d60874ab37a931fc



Edited by sailwyoming on Dec 27, 2018 - 01:19 PM.
Bump, any suggestions?
Greetings Sailwyoming,

Since this is an Alpha bow crossbar issue, not a Nacra beam issue, it would be helpful to start a new thread

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Philip
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I know how it is prevented on a Nacra, but no first hand knowledge of your Cat. Is there a Facebook group, or perhaps join the Hobie forum & ask.
This is the onlyy thing I’ve seen on them. Good luck.
http://https://www.thebeachcats.com/forums/viewtopic/topic/12350#pid27172

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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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