1970 Rondar 505 cracked hull (today)

Discussion in 'Sailboats' started by 500Lonepine, Jul 18, 2014.

  1. sailrob
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    sailrob Junior Member

    I would agree with the above post. I would get help from someone else who has more experience.
     
  2. SukiSolo
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    SukiSolo Senior Member

    So it may have a core of 'X' - quite likely balsa or foam though a bit early for the latter. You can still repair it fine but you need to get to sound dry core areas when you clean up the hole. You then have a choice to rebuild a core, or just make it solid glass. On this one, as she is quite old and has obviously 'worn' at this point, I would solid glass her unless it is quite thick say 6mm +. If you need to replace the core you can either scarf in new foam or use Western Red Cedar (or equivalent) pieces butted together but running longditudinally to allow the curvature.

    Use epoxy, as this will give a superior bond for this type of repair. The glass weight looks to be about 300 gsm - probably a single skin each side. If you solid glass it, chamfer in as per a scarf - ignore the 7:1 ratio, anything over 4:1 will work fine. Personally I would stick with a layer of 200 on the inside a load of layers of 300 finishing off with 200 or even two layers of 200 gsm. Then gelcoat. Much trickier are polystyrene and Nomex cores, believe me.

    It is still actually pretty simple, more a case of having the courage to cut back to sound stuff and chamfer the edges to get a good bond. As long as you are bonding to good dry and clean surfaces, this will repair fine.

    If you don't feel comfortable about doing this, then by all means go and see a professional.
     
  3. 500Lonepine
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    500Lonepine Junior Member

    Thanks guys,

    AndySGray, the WTF chunk once dried became considerably lighter in color. You clearly know much more about this than I. But the material COULD be would, but it now is a kind of plasticky steel gray. I asked people around the house, if they believed the material was organic? My wife said... "Maybe, looks like some kind of glue." Anything else that could be, or is it definitely rotted wood?
     
  4. AndySGray
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    AndySGray Senior Member

    I like your WTF or WTH as a descriptions

    To us limeys that translates as What The Heck:D

    Honestly, after 45 years it could be anything - there was a chemical wood converter which hardened soft wood - inject liquid A then Liquid B - chemistry was based on silicates. Could be a glue from a previous repair, the laminating glue from a plywood, FG Resin wth silica beads, foams of various types, an automotive grade filler (Bondo), or Rondar Secret Ingredient #5. Dont dwell -doesn't really matter as to WTF it is - it has long since ceased any structural role.

    I had a look on the 505 site to see if I could glean any info on construction and frankly I'm no better off

    http://www.int505.org/

    Some boat classes are very weight sensitive - builders would save every ounce they could - fair, finish and paint then weigh the hull and screw on lead bars to bring the hull in JUST on minimum weight. Some sailors insist on older hulls as there is a 'grandfather rights' issue and they don't have a handicap which was applied to newer ones, or are you sailing a 45yr old 505 as its cheap and good fun?

    I'm a little concerned that you don't dig yourself into a hole taking on a repair which is not really for a novice.

    Set the digital camera to flash and pop the inspection covers in the front tank - reach in and take a shed load of photos blind - pick the best to post - might give some idea of where we stand and if this is a localised issue or if you'll be ripping off a couple of square yards of the outer laminates.
    If the inner laminate is intact - you might be able to try it -you'll have a form to work from and build up. An awesome material for building depth upto 3-4 mm is micro balloons - you add it to the resin and it thickens it to a gel consistancy, then add the hardener, you can apply with a spreader like a filler which would have taken 3 or 4 layers of biaxial matt - its still a core - needs to be bonded to matting either side but for quick build and easy sanding...
     
  5. 500Lonepine
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    500Lonepine Junior Member

    Hi,

    Here's a shot of the inside of the bow.

    You can see a darkening working from the centerline up. Right AFTER busting the hole in the bow, I went for a two hour sail. The bow did fill with a bit of water. I'm not sure how much, but there is still couple of quarts in the aft section of the bow.

    To my eye the inside of the bow looks to be very clean accept for wat looks like that "watering." Any thoughts on the darkening? I can post other photos if necessary.


    [​IMG]
     
  6. 500Lonepine
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    500Lonepine Junior Member

    By the way, how does one work from the inside on this boat with the bow tube? Is it possible to get under the tube?
     
  7. AndySGray
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    AndySGray Senior Member

    I think you're lucky and hopefully you won't have to.

    I'm still saying this may be too challenging but the inner surface is in nice enough order that you may be able to if you get a more experienced friend to assist with the glassing.

    Me, I'd do it as follows - though there are many other possible routes.

    Flip the boat over and put on stands - low enough that you can reach all of the damaged area easily but high enough you arent bending too much.

    you may well be removing at least 4 sq feet based on those pics but only the outer laminate and any damaged core - do it a bit at a time and stop when the core seems solid and dry.

    use a grinder VERY CAREFULLY to remove the outer and the sandwich (BREATHING PROTECTION and a disposable coverall and spray sock hood - duct taped to the gloves and you'll still itch for about 3 days).

    feather the edges of the old glass

    you don't want to pry /lever the old core as you risk damaging the inner which you absolutely have to save!

    repair the inner where it is holed - sukisolo's trick with the tupperware might help - ive sometimes glassed onto a sheet of thin plastic let set and then peeled of the plastic to give a solid repair panel which can be glassed on. When hard cover the whole area with a layer of Bi-axial or CSM properly wetted and worked in with lots of resin.

    Dont know how thick the sandwich is so either several layers of matting if very thin, micro balloons if thicker or foam/wood strips if thick.

    Hull should be close to original thickness now - so another layer of Biaxial or two and you want to overlap the feathered original edges, finish with a layer of tissue and a flowcoat of wax added gelcoat.

    If I made that sound simple - it isnt - its simplified!

    excuse the sketch but it might help
     

    Attached Files:

  8. SukiSolo
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    SukiSolo Senior Member

    Well said Andy. I concur with your conclusions, however the OP still needs to establish that there is water inside that laminate. It does look like it, unfortunately and although it is possible to repair it as you outline, whether it is worth it is more debateable.

    Rebuilding a glass boat from the inner is definitely not for the faint hearted. Yes it can be done fine and as good as the original or better. Be warned though getting a really good gelcoat finish is tough. When the areas become big, as this one may be, it is a lot easier to paint it. High build primers come into their own, working up a fair surface.

    I have done such work and in gelcoat on several boats but much newer ones where it was worth the effort. In those cases it was more accident damage rather than rotten/wet core problems. On really big holes, say half way through a hull, the only way to repair them is to remould it in the original mould. Recently I have seen such a case, as the mould was some 2,500 miles away, the hull ws written off.
     
  9. 500Lonepine
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    500Lonepine Junior Member

    Hi thanks guys,

    Are you guys saying that that darker color in the photograph is a "rotten/wet core?"

    Also, even though the boat was a race boat, I'm not racing it. I love sailing it for fun, but am far from a racer. Sukisolo you were wondering weather it was worth repairing? Do you mean just get another boat??

    Also, our sailing season is only two months long here. I did not want to miss the next month so I got some MarineTex white and a 6"x2.5" glass cloth and made some "duct tape" from the mixture. I then applied to the exterior of the hull and smoothed with Saran Wrap.

    My goal was to do a "quick fix" before I could get someone to do it right. Did this do more damage than good? I tried to constrain the MarineTex to the area that I thought would need to be cut out anyway.

    Thoughts?
     
  10. SukiSolo
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    SukiSolo Senior Member

    I am certainly not saying that the dark IS wet, just that it may be so. It is quite possible that you have a balsa core and balsa does have different colours inside itself. Also different colours between differing trees so you may have a mix. Check the colour differences in Western red cedar from almost white to dark brown - sapwood to heartwood. Also with some rosewood from almost sycamore white to very dark brown.

    It is perfectly possible that the layup is end grain balsa and the mix contains simply differing colour timber, and it may be perfectly dry. Without feeling it in ones hands or using a moisture meter it is difficult to say. TBH if it is wet it is like a sponge and the water squeezes out - period.

    Hopefully it is only locally wet and this can be cut out later, when it is repaired properly. Be warned that epoxy will NOT bond to a wet substrate, it must be dry. The drier the better, so ensure it is truly dry before a permanent repair. Once again without a little more investigation , hard to call. Let us hope it is only local. Good luck with her, she is actually a pretty old lady now in dinghy terms, though I have sailed older ones, even if they were wooden!.
     
  11. wet feet
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    wet feet Senior Member

    Looking at the image of the inside of the tank it seems quite possible that the dark area is a screed of microballon paste.It was occasionally used as a syntactic foam core.
    I expect the people that built the boat would have been astonished at the idea that it might still be sailing when it was forty plus years old.
     
  12. AndySGray
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    AndySGray Senior Member

    If it gets you / keeps you on the water for the next month thats a 'good' repair - it may weep a bit and depending on the paint it may even start falling off and need a re-do in a couple of weeks (So what).

    check the lower drains on that tank before hauling her out; if the patch fails - the water wont make the damage worse but the weight of water could do some damage.

    While you're sailing (before /after) do a bit of networking - you might find a local guy with the required skills to be able to help you out after the season - its not that bad a job if the other guy (i.e. you) is doing the sanding/grinding and theres plenty of cold beers on hand.
     
  13. gggGuest
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    gggGuest ...

    I have a similar vintage Rondar moth which has what looks like a thin grainy core. According to Rondar this is most likely to be coremat. It seems unlikely that your boat is different. The thickness will help. Coremat is not going to be more than a couple of mm thick but I should have thought an end grain balsa boat - and it seems rather early for that - would be rather thicker, also I see that premade 1/8in endcore balsa panels are available.

    You know antique 505s are neither high value nor in high demand. Before you get into a big repair job it might well be worth seeing if its more cost effective to find another boat and make one good one from two. If doing the repair is going to be an enjoyable activity in itself then fine, but otherwise, well...
     
  14. 500Lonepine
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    500Lonepine Junior Member

    Hi gggGuest,

    I know that there's no real market for the antique 505s. I'm new to dinghy sailing and don't anticipate ever racing 505s.

    I've sailed my 1970 Rondar 505 4 times now. It has been a flat out ball! The boat is fast and has been super fun. Before I got into sailing I had no idea sailing was an actual sport. What I mean by that is that I thought sailing was about wearing a white hat and drinking Chardonnay.

    I had no idea it could be exhilarating, exhausting, freightening and physically demanding. I love the 505 so far. Maybe it's because I'm new to it, but it seems to require all of my concentration.

    So even though I know there's no real market for the old 505s. I've loved mine cause it has really satisfied my desire for sailing to be a sport. Maybe after I'm a better sailer the boat will become boring, but right now it's amazing.
     

  15. 500Lonepine
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    500Lonepine Junior Member

    Advice on the boom and the outhaul

    Hi,

    A few more questions. I'm using a Proctor D mast and boom.

    I can't understand why the boom doesn't affix to the mast in a more "fixed" or permanant way. Can some one give me advice on this. The boom has slid off the pin a few times when the boom vang was adjusted wrong.

    Also, on a Proctor D, where does the outhaul sheet tie off?
     
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