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NACRA 5.5 uni - project boat, main beam damage  Bottom

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  • Hi all,

    Glad to join the forum and learn from all the experience here. I recently acquired a Nacra 5.5 uni (not assembled) in very good shape, except for some major damage to the main beam. There is a jagged hole torn through the dolphin striker rod area. I don't know whether to repair, replace, or manufacture my own new main beam from blank marine aluminum tubing.

    http://s25.postimg.org/p3jgwd36n/IMG_5453.jpg

    http://s25.postimg.org/lmm074ti7/IMG_5446.jpg

    The full story is here: http://www.catsailor.com/…Number=275533#Post275533

    Thanks for your thoughts! I'll have many more questions to do with setting up and tweaking the boat once the hulls are together.

    Cheers,
    Tom

    --
    Tom
    Nacra 5.5 Uni
    (actually a chopped down 18sq)
    (soon to be 5.5 sloop)
    Northern California
    --
  • check out a local welding shop first, they may be able to cut out damage and put a patch in. if you make a new beam, i'd probably use 6061-t6 tube, 1/8" wall. i have a friend who made one piece beams for an sc20 and no problems with them.

    --
    Mike Conway
    H16
    Hilton, NY
    --
  • I wouldn't bother trying to save it. That damage is too bad and they aren't hard to get. Measure it and Fire Pete begle and dan Berger on here a private message and see if they have one available. Someone else, like Chris Hilliard, may also have a spare.

    --
    Dave Bonin
    1981 Nacra 5.2 "Lucile"
    1986 Nacra 5.7 "Belle"
    Winnipeg, Manitoba, Canada
    --
  • It looks like New England catamarans also has some for sale.

    --
    Dave Bonin
    1981 Nacra 5.2 "Lucile"
    1986 Nacra 5.7 "Belle"
    Winnipeg, Manitoba, Canada
    --
  • Thanks Dave, I'll follow up those leads, much appreciated.
    WolfmanI wouldn't bother trying to save it. That damage is too bad and they aren't hard to get. Measure it and Fire Pete begle and dan Berger on here a private message and see if they have one available. Someone else, like Chris Hilliard, may also have a spare.


    --
    Tom
    Nacra 5.5 Uni
    (actually a chopped down 18sq)
    (soon to be 5.5 sloop)
    Northern California
    --
  • I saw Wolfmans reply, I have a couple of beams, at least 1 V strap, & a couple of the pads that fit on the V strap.
    Measure your beam length, DS rod length, & the distance between the holes that the V strap bolts to. Measure from the inside hole across the beam to the inside hole on the other side. Nacra used a bunch of different V straps.
    You need a new DS rod, I only have 1 spare & am keeping for when disaster strikes. See my album in the Tech help section for building a new one for cheap. Make sure you install BOTH washers. The rod should be 9/16". You do not need that hole in the V strap, the square pad sits on the strap, held by something like Dow 5200, & the pressure from the DS rod. The rod sits in a hole in the pad. the last photo shows both washers, beam preload, & the pad.
    http://www.thebeachcats.c…pictures?g2_itemId=73301

    All the holes on the bottom of your rear beam are to give access to the nuts securing the traveller track, they are just big enough to slide a thin socket into. If you undo them, use nylock(aircraft lock nuts & or a drop of BLUE Loctite to re-assemble.
    I'm in Canada, if you are in a hurry Dan Berger & Pete B would be able to ship cheaper. They are both trustworthy people. Otherwise I can send it next time I'm in the US.
    I would get a used beam, they are not expensive.
    One thing that looks different is the front beam tramp groove. It appears yours is riveted onto the beam?
    All the beams I have seen have a groove integral with the extrusion. Looks like this; (Image from Bill)
    http://www.thebeachcats.com/gallery2/main.php?g2_view=core.DownloadItem&g2_itemId=106889&g2_serialNumber=2
    If funds are scary tight, use the old rear beam, you're not racing in the Nationals. I sailed an N5.7 for two years with a definite "ripple" in the front beam. Drill bigger rivets,(IIRC 3/16" is about the biggest that the cheapo hand riveters will pull), or use an aluminum washer, as backing, with the same size rivets. If you use washers make a tool from a piece of tubing or broomstick, with a hole just smaller than the washer close to the end. Put a piece of masking tape over the hole, then stick the washer to it. Start with the rivet closest to the centre of the beam, if you start at an end, they will be in the way as you try to work inwards. Place a nail into a hole, have a helper push the broomstick in from one end til you hit the nail. Remove nail, & manoeuvre the last 1/4" to line the washer up with the hole. For the rivets in the centre, it will be easier to also slide a second wedge shaped stick in from the other end. This will serve to push the first stick upwards against the hull, & hold the washer snugly while you install the rivet. Push the rivet into the washer,through the masking tape, pull it...repeat til done.
    The hulls look like they are Cal-I-forn-I-A registered, I assume you're close? Pete B is in Big Bear.
    Post any other queries, there are a few 5.5 sailors here.



    Edited by Edchris177 on Sep 22, 2014 - 06:54 PM.

    --
    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
    --
  • Edchris177, thanks so much for your detailed reply - so much useful information there. How to I get in touch with Pete B and Dan Berger? If I can find replacement beam/s in good condition (I only want to do this once) at the same or significantly less cost than making my own new ones, I would consider grabbing them. After hearing all the advice, there is a certain appeal in making my own new beams from blank tube - but my wallet will decide ultimately. I promised my wife this project wouldn't get too expensive!

    I think getting a machine shop to make me a DS rod is a good option. Your step by step albums are very helpful. With the v-strap, I will take the less expensive option between getting a shop to weld a little reinforcement on the underside of the centre hole, or buying a whole strap second hand. I'm curious to remove the pair of bolts on each side holding the strap to the beam, to see if there is as more bad corrosion hiding. That might make the decision for me.

    Would you mind sending me a p.m. with how much you are asking for beam/s, ds support casting/pad, and v-strap? Thanks. I've been away from home a few weeks, but I'll try and measure things soon when I get back.

    My tramp groove is indeed riveted to the beam, and not extruded as shown in your pic. Is this uncommon? Also perplexing, every Nacra thread I've read shows/describes the the anti-rotation in the beam coming from a bolt that threads through the internal beam casting 'half-moon' and into a hole in the hull. My boat has a threaded stud protruding FROM the hull, in each beam cradle. I assume I just need a lock nut on each stud, on the inside of the beam, for the same result, along with two of the internal beam casting 'half-moons' from Murrays. http://www.murrays.com/56-2511.html I can tell I'm going to spend a lot with them after I also get the mast ball and compression tube, and no doubt a few other bits and pieces.

    I'm not far from Tahoe CA, a little north.

    One last thing - how do I make a photo album? I wouldn't mind posting a whole bunch of pics of all the pieces I have for the boat, so anyone interested can comment on anything good/bad/weird that they notice. As I say, my understanding is the hulls do not belong with everything else I have, so there may be some mismatch.



    Edited by sierracat on Sep 27, 2014 - 07:51 PM.

    --
    Tom
    Nacra 5.5 Uni
    (actually a chopped down 18sq)
    (soon to be 5.5 sloop)
    Northern California
    --
  • QuoteOne last thing - how do I make a photo album?

    Click on the tab at the top of page SITE FAQ, Damon has a tutorial there.
    P Begle is usually on here, just look through some of the posts & PM him. I think you could also find Dan Berger by a search. I think if you go into your PM box, you can search out a member.
    If trying to keep a shoestring budget, probably Pete or Dan can get you the beams cheaper, as shipping would be quite a bit less. If they are over 8', price goes up. I don't think I have any extra 1/2 moon chocks, try to get them used, some of those parts are pretty expensive new, & they don't really wear out.
    Do you have the manuals for Nacra? Here is the link.
    http://www.thebeachcats.c…pictures?g2_itemId=35212
    I don't have personal experience with the 5.5, but I have never seen a Nacra with the tramp channel riveted to the front beam, nor have I seen "studs" in the hulls. What year is the boat?
    Are all the bolts these studs, or is it possible they used to be bolts & the heads were twisted off?
    I think I have an old mast ball, it's pretty worn, but I'll give it to you to get on the water.
    PS don't buy the Parts Catalog, I can email you one, I don't think Damon has it cached here.



    Edited by Edchris177 on Sep 27, 2014 - 08:42 PM.

    --
    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
    --
  • http://s25.postimg.org/s55r3nfxb/IMG_5444.jpg

    Not sure what year it is. I've heard that the serial numbers are on the starboard transom, but I couldn't see one anywhere. There's just one bolt stud per side - to stop the beam twisting. It still has the normal holes for the beam straps (4 per hull).

    --
    Tom
    Nacra 5.5 Uni
    (actually a chopped down 18sq)
    (soon to be 5.5 sloop)
    Northern California
    --
  • This thread may help with finding an HIN #
    http://www.thebeachcats.c…nc=viewtopic&topic=14494
    It turns out a number of the Nacras did use the studs you show.
    Do a search for Richard Obren,(maybe Obrian?) in members, I think you access it from your PM box. He used to post a fair bit & has a 5.5 Uni.

    --
    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
    --
  • Thanks Edchris177, and I got your PM, I'll be in touch.

    I'm starting to realize my current beams don't add up. I think perhaps they didn't come from/with these hulls, even if the intention was for them to fit when they were rebuilt. They are 8ft 5in long (is this spec for the 5.5?) and 4" OD, and appear to be 3/16 in thick. The front beam has the tramp track riveted on, as people have pointed out isn't normal. The studs coming out of the hull need corresponding holes in the beams. As I said, the rear beam has holes that don't line up in a way that makes sense, and the front beam it turns out doesn't have holes at all! The beams have a lot of weird holes and stains from previous fittings, as if they were set up on a different boat. The Nacra manual shows the traveller track running the full length of the rear beam. Mine has a stain in the beam where it looks like one used to run full length, but now finishes short, on the inside of each hull. I've learned earlier Nacras may have had these short bolt-on travelers, and later boats had a full length traveller that was extruded. More postings as I unravel the mysteries.



    Edited by sierracat on Oct 01, 2014 - 09:12 AM.

    --
    Tom
    Nacra 5.5 Uni
    (actually a chopped down 18sq)
    (soon to be 5.5 sloop)
    Northern California
    --
  • I have a 5.5 Uni and can take as many pix as you need. It appears you have a hodge podge of parts. Call me if you want 816 436 161 zero.

    --
    Lake Perry KS
    H-18
    N-5.5 UNI +spin
    --
  • Hey, thanks Ricard! I'll definitely be in touch once things start happening with putting it together or fabricating parts. Much appreciated. You could start by sending me a couple of snaps of your trailer, and the way the boat is supported on it? I picked up a light boat trailer I need to modify for my 5.5.

    Thanks.

    RicardObenI have a 5.5 Uni and can take as many pix as you need. It appears you have a hodge podge of parts. Call me if you want 816 436 161 zero.


    --
    Tom
    Nacra 5.5 Uni
    (actually a chopped down 18sq)
    (soon to be 5.5 sloop)
    Northern California
    --
  • Email me. Richard at Northracecars.com

    --
    Lake Perry KS
    H-18
    N-5.5 UNI +spin
    --
  • Update: not a lot of used beams around. Looking at the blank tubing route. I can't measure wall thickness accurately, but it's a little more than 0.0625, and one source I have suggests 0.078 (5/64t) which apparently is an odd size. Thinking about going up to the common 0.125 (1/8in) and filing down the compression tube a hair to fit. Waiting on a quote for a stick of this stuff (4in OD) and I'm sure I'll almost fall over when I hear it.

    Dolphin striker rod: trying to get around the $70 buying a new one, but custom making one mite be too expensive (I don't know any hobbyist machinists). Apparently 9/16th is an odd size for stainless rod, on top of the fine (18) thread. Damn sailboats!

    V-strap: looking at either welding a brace over the corrosion at the centre of the V (isolating potential cracking and the mysterious drilled hole) while also acting as a dolphin striker rod casting. Or ordering the flat bar and bending a new one. Talking to a shop to figure out what alloy it is. He thinks 7 series (bendable, not very weld able) so may not be able to fix old one.

    Oh, and to top of the weird sizing of all the materials (apparently this is deliberate by many manufacturers so that people have to buy original parts, not make them like I am) the trailer steel (channel) is an odd size, so I can't match it easily. Not that I care to much about that, since I'm not trying to fit anything to the old frame, just adding across the top of it.

    --
    Tom
    Nacra 5.5 Uni
    (actually a chopped down 18sq)
    (soon to be 5.5 sloop)
    Northern California
    --
  • I don't belive the 5.5 sl or uni ever had the bridle tangs on the outside of the hull. You may have an old 18 square that has been cut down in width. They had the tangs on the outside.

    --
    Ron
    Nacra F18
    Reservoir Sailing Assn.
    Brandon, Mississippi
    --
  • nacra55I don't belive the 5.5 sl or uni ever had the bridle tangs on the outside of the hull. You may have an old 18 square that has been cut down in width. They had the tangs on the outside.


    How do you mean? Without a jib, the uni doesn't have a single forestay and a bridle foil, it has twin front stays and then the aft pair (not sure if my terminology is correct). Are you saying the two chain plates on the outsides of each hull should be on the inside? That doesn't seem right. Thanks for your observations though, I'd like to understand better.

    --
    Tom
    Nacra 5.5 Uni
    (actually a chopped down 18sq)
    (soon to be 5.5 sloop)
    Northern California
    --
  • nacra55I don't belive the 5.5 sl or uni ever had the bridle tangs on the outside of the hull. You may have an old 18 square that has been cut down in width. They had the tangs on the outside.


    I think the uni rigged boats had tangs on the outside.

    http://www.thebeachcats.c…nc=viewtopic&topic=11472

    "for a uni rigged boat, like the 18m2, the best position for the bridal tang is on the outside of the hull, but for a jib equipped cat the bridal tangs need to be on the inside of the hull"

    --
    Tom
    Nacra 5.5 Uni
    (actually a chopped down 18sq)
    (soon to be 5.5 sloop)
    Northern California
    --
  • Album of the boat parts here: http://thebeachcats.com/pictures?g2_itemId=111519

    --
    Tom
    Nacra 5.5 Uni
    (actually a chopped down 18sq)
    (soon to be 5.5 sloop)
    Northern California
    --
  • Added some more pics to the album. More detail on tramp type/condition, traveller, wire rigging, trapeze, pivmatic, etc. http://www.thebeachcats.c…ictures?g2_itemId=111519

    --
    Tom
    Nacra 5.5 Uni
    (actually a chopped down 18sq)
    (soon to be 5.5 sloop)
    Northern California
    --

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