I have two Nacra 5.2's. The first is a 1981 that I picked up for free (gotta love those that don't pay their club storage fees) and a 1977 that I just picked up for $150. I'm in the middle of restoring the 1981 all the way down to the gelcoat, and plan to do the same on the 77. However, before getting too far into the 77 I have a question about the rear bulkheads. The 81 has full bulkheads (top to bottom and sided to side) at the front and rear crossbeams, but the 77 only seems to have a half bulkhead (top to nearly the bottom on the outside skin) at the rear crossbeam. I assume this is as produced since it is the same in both hulls, but I wanted to make sure that it wasn't that someone in the past short shifted a repair. Does anyone have experience with this old hull design?

If it is as designed, is anyone aware of issues with this design that I should address? I'll be doing some glass work at the rear inspection ports to beef up the deck where it has flexed over the years from trapping, but after doing the same on the 81 I don't think it possible to do much bulkhead work through the port, so that means lifting the deck, which I hope to avoid.

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Craig
Windrider Rave Hydrofoil
Nacra 5.2 Restored and heavily modified
Nacra 5.2 (one under restoration)
Nacra 5.7
Nacra 5.8NA
SoCal
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i would assume that nacra went from a partial bulkhead to a full bulkhead in such a short space of time because they found the half bulkheads weren't working...

if i was to do a full rebuild of my 1982 5.2, with the aim of keeping it going another 30 years

i would be lifting the forward decks and glassing in a 1" thick high density foam bulkhead, glassed on both sides, about 18" forward of the mainbeam

that seems to be about where the major forces are working at pulling the stringers off the hulls

those stringers were only chopped-mat laid over cardboard tubes and on many boats after a hard life have started lifting off and once they are gone, the hulls snap off



Edited by erice on May 19, 2013 - 03:23 AM.

I took some photos inside the hull of an early 5.2, that we destroyed. they are in an album here.
http://www.thebeachcats.c…ictures/?g2_itemId=82844



Edited by Edchris177 on May 19, 2013 - 07:12 AM.

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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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Thank you for the suggestions. I did find a stringer separated in an area on my 81 and put an access hold just forward of the beam and made repairs. I couldn't locate any others that had or appeared to have separation issues so I made a foam sandwich piece and epoxied it back under the deck hole for support and then epoxied the round deck piece back in. Maybe I'll take your suggestion about pulling the decks and adding a bulkhead. It makes it nice, I have Aircraft Spruce just 10 minutes away, so I can run down and get any composite products I want, and be back to work in less than an hour.

Has anyone found the perfect tool to separate the deck? I assume there is some type of electric or air tool that would have a FINE chisel attachment, but I'm drawing a blank at the moment.

Also, has anyone found where you can purchase 4" round mast extrusions with the keder groove to make new crossbeams? I was just going to purchase new tube and some keder rail, cut the flat tab off the keder rail, and aluminum soldier or weld the keder round to the beam. But if I can purchase new tube with the keder slot I'd rather do that. I'm finding that most have royally screwed up their crossbeams or the electrolysis is taking its toll. I'm making fittings for wing seats that fit in the end of the crossbeams, and there can't be any oval or dented tube for my setup to work.

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Craig
Windrider Rave Hydrofoil
Nacra 5.2 Restored and heavily modified
Nacra 5.2 (one under restoration)
Nacra 5.7
Nacra 5.8NA
SoCal
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I just used a small chisel and a big screwdriver to remove the decks. This subjects them to excessive flex and does soften them somewhat. I epoxied mine back on and after a season of sailing small hair-line cracks are visible in the new gel coat. Perhaps if you could make a small chisel that is thinner than normal you could minimize damage.
Dennis

I'd be really hesitant to use a power tool -- more so to use an air tool -- to separate the decks. Tapping a putty knife with a hammer/mallet goes really quickly (half hour or so for a deck) and does a good job. I use a chisel to start the separation in a few places and the rest with a couple putty knives. I've only done it 3 times, so I'm no expert, but the 2nd and 3rd time I got them off quickly without any damage.

The dagger well is a pain on the rear decks.

I've only put one of the decks back on, and I didn't take much effort to clean the hull or deck of the old glass, so it stands 1-2mm proud of where it originally was, but it's certainly solid.

I've got a couple extra beams if you can't find the extrusion, but I imagine you could find someone much closer to you with extra 5.2 beams if you look. Neglected 5.2s aren't hard to come by.

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Rob
OKC
Pile of Nacra parts..
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Craig

Where in SoCal are you located, I am also in SoCal and about to do the same thing to my n5.2 and would like to see what you have done and how you did it if you wouldn't mind. I have worked on several other cats I have or have had from miner to fairly major repairs but haven't taken the deck off a n5.2 yet.

Please send me a pm when you have time.

Thanks

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Jeff O
N5.0
solcat 18(sold),
N5.2,
H16
Camarillo CA
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Jeff,

I'm down in Corona just south of the 91 & 15 interchange. I haven't done anything yet to the 77 with the partial aft bulkhead. It's still sitting in my hanger at the Chino airport and I'm trying to decide if it is the next in line for restoration, or the 5.8NA.

I beefed up the rear deck area on the 81 where I assume everyone puts their foot when out on the trap. Both boats have a lot of flex there and cracked gelcoat, so I laid up several strips of glass under the deck and around the corner onto the side and across the stringer. Tough as nails now. Also had a stringer loose up forward in one hull that I had to fix. But I didn't pull the decks on this boat to get to it. As far as I could see the separation was only about 8" long and I assume from someone standing there when trying to right the boat. The glass over the stringer was actually cracked parallel to the stringer right at the hull. I was able to put a 5" hole in the deck to access and make the repairs, then built up a foam sandwich and epoxied under the deck and across the hole for reinforcement and to have something to sit the piece of deck on that was removed.

I just finished shooting with bright lime green gelcoat this afternoon, so hopefully this project is getting close to being finished. Still need some new rigging, possibly a bridle foil so I don't loose so much jib when going with a self tacker, and also to add some support to keep the hulls from moving up forward, new square top main, new tramp, and some wing seats. Probably too much money into the old boat, but it will look as close to new as one can get, and will still be a fraction of the price.

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Craig
Windrider Rave Hydrofoil
Nacra 5.2 Restored and heavily modified
Nacra 5.2 (one under restoration)
Nacra 5.7
Nacra 5.8NA
SoCal
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Many a fool can screw up in 5 minutes what it takes hours to fix. Use a chisel and a putty knife. It ain't that hard.

Quote

I'd be really hesitant to use a power tool -- more so to use an air tool -- to separate the decks. Tapping a putty knife with a hammer/mallet goes really quickly (half hour or so for a deck) and does a good job. I use a chisel to start the separation in a few places and the rest with a couple putty knives. I've only done it 3 times, so I'm no expert, but the 2nd and 3rd time I got them off quickly without any damage.

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Nacra 5.2
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Ya, if I lift the deck I'll probably use the putty knife. But I did see the tool I was thinking about this weekend at Home Depot. It's in the Dremel section and has blades that appear move side to side slightly. I figured the scraper blade would allow for good control, but I've never seen one of these tools in action, so I don't know if they are as controllable as the rotary Dremels.

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Craig
Windrider Rave Hydrofoil
Nacra 5.2 Restored and heavily modified
Nacra 5.2 (one under restoration)
Nacra 5.7
Nacra 5.8NA
SoCal
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