Ideas for Improving the Top section

Discussion in 'Laser Talk' started by rippa, Nov 5, 2007.

  1. madyottie

    madyottie Apprentice

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    So, at risk of being accused of trying to kill our one-design game, what would be so bad about Laser doing a bit of a redesign? Composite top section AND a slightly modified sail design?

    After all, most of the complaints that go on this forum involve either broken top sections, or new sails being worthless after a week.

    It wouldn't take much effort for the sailmaker to add a tiny bit of luff curve higher up, which would let us use a softer section without any major loss of performance. Sure, we may need to re-learn how to use our cunningham and vang, but it wouldn't take us long!
     
  2. Steve_Landeau

    Steve_Landeau New Member

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    I'm glad at least one other skipper read it the way I did. I didn't get a chance to look up the adhesive today at work, will get it tomorrow. As for end for ending, it can still be done, but you'll probably have to cut off the sleeve. Hopefully without the weak spot, end for ending won't be necessary.
     
  3. sailchris

    sailchris Member

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    My interpretation of the rules leads me to the conclusion that use of an adhesive to secure the sleeve to the top section is illegal.

    The problem is that you have both missed the official interpretation of "fastenings," which is on the bottom of page 38 of the PDF version of the ILCA 2007 Rules. The interpretation reads:

    "1. Fastenings (Rule 26(c)) shall include screws, bolts, nuts, washers and rivets." (emphasis added)

    Since an official interpretation of the meaning of fasteners is provided in the rules, the standard proviso applies, i.e. if it's not specifically allowed then it's illegal. The sleeve is secured to the top section with a fastening. Replacement of fastenings with alternatives is allowed. Fastenings (and presumably all their allowable "alternatives") include "screws, bolts, nuts, washers and rivets". Adhesives are not specifically listed among the allowed fastenings, so the use of an adhesive to secure the sleeve to the top section is therefore against the ILCA rules.
     
  4. 49208

    49208 Tentmaker

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    Well, illegal or not, hopefully Tracy is reading this and reporting back to the technical committee that there is indeed at least one adhesive that appears to be working.

    We also have VTGent's solution of moving the rivet into the lower portion of the collar.

    It would be great to find out that the builders are following up (like contacting Steve L) on this and doing their own testing (and also a smart public relations move for them). Both are simple solutions, the adhesive adds some cost for the builder and makes it more costly for us to end for end the spar, moving the rivet doesn't.
     
  5. Laserite

    Laserite New Member

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    Hi, have you used one? I have, and in a fleet where the top three boats always finish within 5-10 seconds of each other opver a 60 minute race . Well it was 20 knots and guess what, I finished exactly wher I normally do, 2nd in race 1 and 3rd no race 2 - just like I would probably have if I had the standars aluminium section. I noticed NO NONE NIL performance advantage. The only advantage wqas it didn't permenently nbend.
     
  6. Deimos

    Deimos Member

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    Was that with your normal (alu mast) sail or does it come with its own different sail (to account for its different bend characteristics) ? One would expect a mast with different bend characteristics to have a different shaped sail.

    Ian
     
  7. Merrily

    Merrily Administrator Staff Member

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    As I said before, I've used the composite top section, handed to me by Tracy Usher when I sailed with him at St Francis Yacht club in San Francisco. You use the current class legal Radial sail. There's no modified sail for it (yet?).
     
  8. Steve_Landeau

    Steve_Landeau New Member

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    Hi, guys.
    Here is what I'm using; It's Scotch-Weld 2216/AB. Aircraft Spruce stocks it, but I have a quart here in Long Beach,CA if anyone wants to try it.
    http://www.aircraftspruce.com/catalog/cspages/3mAdhesive2216.php
     
  9. Clive Humphris

    Clive Humphris ILCA Technical

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    My reading of the rule is that adhesive may be legal in that in 26c it says that alternatives to fastenings are specifically allowed. The class rule interpretations only say that fastenings include screws, bolts, nuts, washers and rivets. 26c specifically allows alternatives which I would suggest can include adhesive. Any other legal opinions out there?
     
  10. sailchris

    sailchris Member

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    The alternatives could legally include an adhesive if the rules did not also contain the restriction that things not specifically allowed are illegal. Adhesive is something not specifically allowed. Adhesive is illegal.

    I think adhesive is a good idea, but it the adhesive fails the top section would fall into the bottom section.

    I think a better solution would be to replace the sleeve with a one piece, cup-shaped plastic molding that would be press-fit into the top of the bottom section. The top section would then be able to have symmetrical ends with no sleeves. The top section would fit snugly into the cup-shaped molding.
    Alternatively, the cup-shaped molding could be attached to the top section, replacing the current sleeve and end cap. The end cap is a problematic part anyway, always getting stuck etc. In this version, the cup shaped molding would be press-fit onto the top section and would fit snugly into the bottom section (as the current sleeve fits now). If needed, an adhesive could be used to secure the molding to the top section to prevent if from slipping off when the top section is removed from the bottom section after sailing.
    Both of these ideas could be implemented without rivets and would be simpler than the current system.
     
  11. Ross B

    Ross B Guest

    but remember what was said earlier, they tried it and had problems with it because not all lower sections are exactly the same size, and it is hard to get a good fit
     
  12. vtgent49

    vtgent49 Member

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    I believe that Interpretation 1) may have been an attempt to narrow the alternatives, but it sure does this poorly.

    26 (C) now reads that you can replace "Screws, bolts, nuts and rivets" with alternatives. It doesn't say "with alternative fasteners".

    It's hard to believe that someone thought 1) clarified anything at all if the intent was to eliminate an alternative like adhesive. What it does do is clarify what can be replaced with alternatives.

    If you are bothering to look at all these rules, then tell me what you think about moving the rivet down 2 inches when you end for end the top. It seems to fit ok under 26 a) and c). 26 b) says shall be placed in a position conforming to the measurment diagram. OK, but the diagrams don't mention rivets at all? So, maybe MTR is already legal and doesn't need a rule change like a CF spar, deep collar and the sleeve?



    Al
     
  13. sailchris

    sailchris Member

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    That should also be the case with the current sleeve, and everyone seems to make that work just fine. Besides, it's easier to adjust the diameter of a plastic molding to obtain a good fit than to adjust the diameter of the aluminum mast.
     
  14. Ross B

    Ross B Guest

    but I think they ( Vanguard) would want to make one size, not multiple different sizes for ease of sale and production
     
  15. fracisco

    fracisco New Member

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    Exactly. You design and build the 'socket' to account for the tolerance stack up of the upper and lower sections, bare, and let people use tape for the fine tuning/shimming of the interface. It has to be less expensive to produce an injection molded 'socket', than to produce the upper section injection molded piece (actually 2 pieces), and then the labor to align, drill, and rivet into place.

    Even if the 'socket' pulls out of the lower and stays attached to the upper at the end of the day, it has to be a better setup than the current approach.
     
  16. Ross B

    Ross B Guest

    I still think the best way would be for all top sections, for 4.7/radial/full to be carbon/composite/whatever and just have the sleeve's molded in like the test models are now. Can't get much better then that.
     
  17. sailchris

    sailchris Member

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    That's right. I didn't mean that they would produce different sizes. Also, if the version where the socket stays attached to the bottom section is used, then it could be press-fit into the bottom section at the factory, the plastic deforming as it is inserted to take into account variations in the bottom section diameter. Then the top section could just be slid into and out of the socket during rigging/derigging. Either way, the system must allow for a tight connection between the top and bottom section so that the mast has as smooth of a bend as possible.
     
  18. Ross B

    Ross B Guest

    if it was press fit, and not removable (maybe?), if and when they happen to break, that would possibly mean you would have to replace your bottom section. I personally feel it would be better if the cup were removable for maintenance and such
     
  19. sailchris

    sailchris Member

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    You could always cut it out. I had to replace my boom gooseneck plug recently and it wouldn't just come out after the rivet was drilled out. I had to cut it out from the inside.
     
  20. Steve_Landeau

    Steve_Landeau New Member

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    Certainly better than the alternative; your top section breaks because of a rivet hole... you lose the top section AND your sail! If adhesive slipped, you'll lose some sail trim. I'll take the latter.
     

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