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Bow chainplate blowout #273877
07/13/14 01:29 PM
07/13/14 01:29 PM
Joined: Feb 2009
Posts: 12
Virginia
BayMaven Offline OP
stranger
BayMaven  Offline OP
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Joined: Feb 2009
Posts: 12
Virginia
Has anyone had to deal with this?

[img]https://plus.google.com/u/0/photos?pid=6030345076995377378&oid=100427919838747153607[/img]

The boat is an old nacra 5.2 which is a blast to sail in big wind. Unfortunately, big wind + big boy on wire = plate blowout. No wire breakage was evident and the rig and sails were recovered with a small puncture wound in the jib from the flying plate.

Also - has anyone ever upgraded to a lighter mast? ...was it worth the trouble and expense?

Last edited by BayMaven; 07/13/14 01:31 PM.
-- Have You Seen This? --
Re: Bow chainplate blowout [Re: BayMaven] #273883
07/13/14 08:46 PM
07/13/14 08:46 PM
Joined: Aug 2011
Posts: 774
Greenville SC
bacho Offline
old hand
bacho  Offline
old hand

Joined: Aug 2011
Posts: 774
Greenville SC
Your link doesn't seem to work for me. Maybe the pictures are not public?

Re: Bow chainplate blowout [Re: BayMaven] #273885
07/14/14 03:29 AM
07/14/14 03:29 AM
Joined: Jun 2009
Posts: 519
Petten Netherlands
N
northsea junkie Offline
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northsea junkie  Offline
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Joined: Jun 2009
Posts: 519
Petten Netherlands
The photo shows that the shroud-pin plus its internal plate has completely broken out the hull.

All can be repaired with a thick layer of glass laminate on the inside and combined with some glass on the outside. Only problem is to get access to the inside of the hull at that particular place.

Why are you pondering about a lighter mast after this experience in big wind?


ronald
RAIDER-15 (homebuilt)

hey boy, what did you do over there, alone far out at sea?..
"huh....., that's the only place where I'm happy, sir.
Re: Bow chainplate blowout [Re: BayMaven] #273890
07/14/14 04:24 AM
07/14/14 04:24 AM
Joined: Jul 2006
Posts: 304
H
Hullflyer1 Offline
enthusiast
Hullflyer1  Offline
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H

Joined: Jul 2006
Posts: 304
Is it he shroud attachment or the bridal wire attachment

Re: Bow chainplate blowout [Re: BayMaven] #273891
07/14/14 04:42 AM
07/14/14 04:42 AM
Joined: Jun 2006
Posts: 431
Netherlands
DennisMe Offline
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DennisMe  Offline
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Joined: Jun 2006
Posts: 431
Netherlands
I have a Nacra 5.2. Its the Bridle wire attachment point. The shrouds on that boat attach right by the dagger boards.

Lots to upgrade on that boat but a lighter mast wouldn't be on my list unless someone had a nice one piece carbon mast for free...

I'm with Northsea Junky (who needs a shorter nick; "Diehard" would be an option ;-)

You can lift the lids off the bows with a strong putty knife and a chisel, just work a round methodically and 'feel your way' in order to not damage the hulls or lids (or your hands for that matter!).

Re: Bow chainplate blowout [Re: DennisMe] #273893
07/14/14 07:58 AM
07/14/14 07:58 AM
Joined: Jun 2009
Posts: 519
Petten Netherlands
N
northsea junkie Offline
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northsea junkie  Offline
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Joined: Jun 2009
Posts: 519
Petten Netherlands
Originally Posted by DennisMe


I'm with Northsea Junky (who needs a shorter nick; "Diehard" would be an option ;-)




Thanks Dennis, for your support, but I'm really no "Die-hard".

I know it maybe seems that way in the eye of some spectators, but it's all against my will.

I'm driven by my sigh to the Northsea, which put me sometimes in unexpected harsh conditions. But by this junkie behaviour I damage my 68 year old body severly. Somehow I'm compelled to do so.

Yes I know, just like in the movie with Bruce Willis.


ronald
RAIDER-15 (homebuilt)

hey boy, what did you do over there, alone far out at sea?..
"huh....., that's the only place where I'm happy, sir.
Re: Bow chainplate blowout [Re: BayMaven] #273894
07/14/14 09:06 AM
07/14/14 09:06 AM
Joined: Jun 2002
Posts: 1,658
Florida Suncoast, Dunedin Caus...
catman Offline
Pooh-Bah
catman  Offline
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Joined: Jun 2002
Posts: 1,658
Florida Suncoast, Dunedin Caus...
Originally Posted by BayMaven
Has anyone had to deal with this?

[img]https://plus.google.com/u/0/photos?pid=6030345076995377378&oid=100427919838747153607[/img]

The boat is an old nacra 5.2 which is a blast to sail in big wind. Unfortunately, big wind + big boy on wire = plate blowout. No wire breakage was evident and the rig and sails were recovered with a small puncture wound in the jib from the flying plate.

Also - has anyone ever upgraded to a lighter mast? ...was it worth the trouble and expense?


Not hard to repair but it will require a bit of knowledge and time. You have to take the decks off at least part way. I say decks because you will have to repair the other side before it pulls out too. You have to change the way that tang is installed and supported especially since the hull is ripped out at that spot. Check your PM.


Have Fun
Re: Bow chainplate blowout [Re: catman] #273897
07/14/14 12:18 PM
07/14/14 12:18 PM
Joined: Nov 2008
Posts: 490
catandahalf Offline
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catandahalf  Offline
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Joined: Nov 2008
Posts: 490
Is the boat an older model without a core, or is it one of "Catalina's" foam core editions? What is the hull number? Whether it is cored or not-cored makes a final difference, because you are not faced with just lamination; core replacement will require a more lengthy and detailed retro.

Remove the entire deck because if you don't they become a pain to seal properly. Be careful as those deck plates are very rare.

As a former NACRA dealer, I wish you the best,

Bert Rice
Nacra 5.2 and 5.5 SL (retired)

Re: Bow chainplate blowout [Re: BayMaven] #274000
07/17/14 09:55 PM
07/17/14 09:55 PM
Joined: Feb 2009
Posts: 12
Virginia
BayMaven Offline OP
stranger
BayMaven  Offline OP
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Joined: Feb 2009
Posts: 12
Virginia
Thanks for the comments. The google plus image is public ... not sure how to paste actual photo here - html is disabled.

"The blowout" is the port bow forward chainplate - bridle tang - which blew completely through the fiberglass. Amazingly, the deck is still intact with no obvious cracks. I'll check, but as best I can tell this is a 1980 5.2 no core. I agree that any chainplate upgrade needs to be performed on both hulls. They are not robust enough for my taste. Now I'm worried the shroud chainplates might be suspect.

I'm fairly comfortable handling epoxy and glass - I brought these hulls back from their weedy resting place in VA Beach and re-glued deck delam as well as sand/fair/awlgrip both hulls. Fixing her is only economical as a DIY project.

Here is a pic of better days... [img]https://plus.google.com/u/0/photos/...4544068818&oid=100427919838747153607[/img]

As for carbon ... I've already concluded that would be insane ...ly expensive.

Sail Fast!

Last edited by BayMaven; 07/17/14 10:05 PM.
Re: Bow chainplate blowout [Re: BayMaven] #274010
07/18/14 06:12 AM
07/18/14 06:12 AM
Joined: May 2006
Posts: 1,381
Kingston SE South Australia
JeffS Offline
veteran
JeffS  Offline
veteran

Joined: May 2006
Posts: 1,381
Kingston SE South Australia
To post pics they need to be small size, click on "Switch to Fully Reply screen" button at bottom of the reply screen
click on "File Manager" button, click on "Browse" this enables you to find the file on your computer, find what you want click on it, once happy click on "Add File" click on "Done adding files" then it's done


Jeff Southall
Current boats
Nacra 5.8 1703 Animal Scanning Services
Nacra 5.8 1667 Ram Raider
Nacra 18 Square
Arrow 1576
Re: Bow chainplate blowout [Re: BayMaven] #274015
07/18/14 02:20 PM
07/18/14 02:20 PM
Joined: Oct 2002
Posts: 307
maui
jollyrodgers Offline
enthusiast
jollyrodgers  Offline
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Joined: Oct 2002
Posts: 307
maui
[Linked Image]
You had the BB code there. The problem was that you had linked to the entire collection.

You can buy a yard of carbon online for $25-40 and that should be enough for your repair. Carbon and epoxy is the way to go for strong repairs if racing rules are not a problem.

Re: Bow chainplate blowout [Re: jollyrodgers] #274017
07/18/14 05:05 PM
07/18/14 05:05 PM
Joined: Nov 2008
Posts: 490
catandahalf Offline
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catandahalf  Offline
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Joined: Nov 2008
Posts: 490
Lighter and stronger - good advice from Maui!

Re: Bow chainplate blowout [Re: BayMaven] #275925
10/26/14 07:04 PM
10/26/14 07:04 PM
Joined: Feb 2009
Posts: 12
Virginia
BayMaven Offline OP
stranger
BayMaven  Offline OP
stranger

Joined: Feb 2009
Posts: 12
Virginia
I have started the repair. Progress is documented on google+ ... https://plus.google.com/u/0/photos/100427919838747153607/albums/6030345077259053265

Finishing up is dependent on weather and available time. And how strongly the urge to fix the white topcoat is. However, sailing down in FL this winter is a motivator.

Last edited by BayMaven; 10/26/14 07:05 PM.
Re: Bow chainplate blowout [Re: BayMaven] #275932
10/27/14 02:18 AM
10/27/14 02:18 AM
Joined: Jun 2009
Posts: 519
Petten Netherlands
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northsea junkie Offline
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Petten Netherlands
I can see you do it carefully.

Is this the original position of the plate in the hull?


ronald
RAIDER-15 (homebuilt)

hey boy, what did you do over there, alone far out at sea?..
"huh....., that's the only place where I'm happy, sir.
Re: Bow chainplate blowout [Re: BayMaven] #275943
10/27/14 09:30 AM
10/27/14 09:30 AM
Joined: Jun 2002
Posts: 1,658
Florida Suncoast, Dunedin Caus...
catman Offline
Pooh-Bah
catman  Offline
Pooh-Bah

Joined: Jun 2002
Posts: 1,658
Florida Suncoast, Dunedin Caus...
Originally Posted by BayMaven
I have started the repair. Progress is documented on google+ ... https://plus.google.com/u/0/photos/100427919838747153607/albums/6030345077259053265

Finishing up is dependent on weather and available time. And how strongly the urge to fix the white topcoat is. However, sailing down in FL this winter is a motivator.


Looking good.

I would make sure that plate is at least 3/16" thick. You could also remove a little more of the forward sealing surface of the hull if you think it would help with room to work in there. Before you glass that plate make sure you add some glass to the inner hull where that plate will rest. I realize the torn hull will be beefed up but the other hull should be beefed up also. The most important thing is to get good adhesion. Sand well and pre wet the areas with epoxy before adding parts or glass. When you get ready to put that tang in bed it in a blob of epoxy putty to prevent any voids. Mix mill fiber in to that putty so it's strong. If you have any questions you want to discuss feel free to call me.

You can just brush some gelcoat over the repair area and do the fine finish later. You should cover the epoxy to protect it from the UV.


Have Fun
Re: Bow chainplate blowout [Re: BayMaven] #275944
10/27/14 09:40 AM
10/27/14 09:40 AM
Joined: May 2003
Posts: 4,451
West coast of Norway
Rolf_Nilsen Offline
Carpal Tunnel
Rolf_Nilsen  Offline
Carpal Tunnel

Joined: May 2003
Posts: 4,451
West coast of Norway
We did it like this to align the forces pulling on the chainplate and spread them to the hull.

Plywood was reinforced with glass on both sides.
Steel was cleaned and sanded, them glued to the plywood with thickened epoxy.
A couple of layers of glass on top again so the steel is properly sandwiched.
Then the bulkhead was installed in the hull and fixed with thickened epoxy and glass tape.

[Linked Image]

Guy in the pic liked the idea. Phill Brander was the one who came up with the idea and layup.

With the setup you are working on I would worry about lifting off the deck as it looks like there will be some leverage working there?

Re: Bow chainplate blowout [Re: BayMaven] #275952
10/27/14 05:59 PM
10/27/14 05:59 PM

S
Scarecrow
Unregistered
Scarecrow
Unregistered
S



With all due respect to you, Phill and a whole lot of other people who have done similar (which includes most wooden Taipans) that detail is ****. Epoxy won't stick long term to ali or stainless. This is not just an opinion it is fact. My boat was built with a similar detail by arguably the best wooden Taipan boat builder in the classes history and just before I bought it one of the chain plates pulled out. The boat was then taken by the previous owner to another experienced boat builder who "fixed" it using a similar detail and 3 years later I got a call from my club to say the mast had fallen down over night because a chainplate had pulled out. My chainplates are now bolted into the boat. Rolf in your photo a couple of small stainless angles bolted or welded to the chain plate and then through the frame would be literally 100 times stronger. The traditional way to detail that fitting would be to twist the legs after it had passed through the hull skin then through bolt them to each other through the frame.

Re: Bow chainplate blowout [Re: BayMaven] #275953
10/28/14 12:44 AM
10/28/14 12:44 AM
Joined: May 2003
Posts: 4,451
West coast of Norway
Rolf_Nilsen Offline
Carpal Tunnel
Rolf_Nilsen  Offline
Carpal Tunnel

Joined: May 2003
Posts: 4,451
West coast of Norway
Interesting!

The plate was drilled so there are lots of holes there and thickened epoxy used to build fillets before glassing over fills these holes. This would increase surface area and give improved mechanical strength. Comparable to embedding a bolt in epoxy.
Would this change your opinion or is this also done in the "standard but bad" way you mentioned?



For the chainplates we went for carbon chainplates glued to the hull. Stainless was to hard to work with.

Last edited by Rolf_Nilsen; 10/28/14 02:53 AM.
Re: Bow chainplate blowout [Re: Rolf_Nilsen] #275954
10/28/14 03:48 AM
10/28/14 03:48 AM
Joined: Apr 2013
Posts: 858
Victoria Australia
Pirate Offline
old hand
Pirate  Offline
old hand

Joined: Apr 2013
Posts: 858
Victoria Australia
There's pros and cons for both methods, the physical fixing of the chainplate with a bolt through the frame will eventually cause issues in the long term..... The timber frame WILL eventually shrink somewhat and the bolting then becomes loose which allows the chainplate to move ever so slightly, once that movement has been achieved it will slowly work against everything else that's retaining it in place.

The timber frame is a great way to spread the load over a greater area, this reduces the strength required in a specific area such as the original posters fitting would have required in the small area it used as the fixing point.


I guess the question is really one of time..........

Just how many years should we expect to get from setup A versus setup B ????

The OP's boat was probably designed with a "life expectancy" of X amount years of service, anything after that is probably a bonus or a headache ...... depending on how much work it requires in order to keep it going
wink


Yar, & this ere post be done without a sin'le drop o' rum passin' me lips

Kingy
started with Impara Cadet #3 / Mosquito #245
& now Mosquitos #1182 & #1740

Re: Bow chainplate blowout [Re: Pirate] #275956
10/28/14 05:32 AM
10/28/14 05:32 AM
Joined: Jun 2001
Posts: 12,310
South Carolina
Jake Offline
Carpal Tunnel
Jake  Offline
Carpal Tunnel

Joined: Jun 2001
Posts: 12,310
South Carolina
Fiberglass and stainless will have different expansion rates in different temperatures so anything that just "pins" it in place (epoxy through holes, etc.) will likely fail over time. Bolts aren't the answer either because they can create very high compression stress on very small surface areas of fiberglass leading to cracking and failure. Wood is nice too, but, as someone pointed out, it suffers from the same same high compression loading from bolts and will compress over time.

Nacra catamarans built around the 90's (and I presume still today) use a method on the side stay chainplates where the chainplate is T-shaped with holes in the "T" section. Those holes holes are filled with long strand fiberglass roving. That plate and roving is glued in place and the roving is fanned out on the hull. Even if you get some mild separation of the steel and fiberglass, the roving that is woven through holes in the stainless will keep it in place. A Nacra 20 is shown below (and granted, this could have been made to look a lot prettier on the inside).

I whacked this boat so hard that the chainplate got a little loose. I built a pressurized cap and pushed some epoxy around the chainplate from the outside and firmed it back up.

[Linked Image]
[Linked Image]

I used a similar method to make a carbon fiber beam strap for a custom built A-cat that was starting to crack around where the rear beam connected to the hulls. Once the carbon roving entered the hull, I wet it out and fanned it out on the inside of the hulls.

[Linked Image]

[Linked Image]

You'll also notice the Orange N20 fenced in the backyard. That's "The General" and that dog was so mean it had to stay chained up.


Jake Kohl
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