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Nacra 5.7 dolphin striker mast support rod  Bottom

  • I bought a 1994 Nacra 5.7 late this summer and sailed it in August and September. The boat is now out for winter and I am trying to make some repairs. The dolphin striker mast support rod is bent and I cut the top of the rod with a sawsall and removed the nut. The boat spent it's previous life in salt water and it appears that the rod is corroded to the compression sleeve. The sleeve and rod are spinning freely but are not coming out. I feel like I just opened a can of worms and wonder how I can get the rod and sleeve out so I can reinstall a new sleeve and rod. I read the topic:

    http://www.thebeachcats.com/index.php?module=forums&func=viewtopic&topic=16096

    but it looks like I am not so lucky and may have made my life much harder. I will order a compression sleeve from Murrays.com tonight. How can I get the rod and sleeve out without damaging the cross beam?

    Thanks,
    Eric
  • Hi Eric, it would be my guess that the rod, which is stainless and the sleeve, anodized aluminum, have seized due to galvanic corrosion which is common in a salt water environment. It may be possible to break loose by spraying with PB Blaster or another penetrating oil, WD40 won't do it. You could also heat it up and try and drive the piece of rod out of the sleeve.

    --
    Mike Conway
    H16
    Hilton, NY
    --
  • In my experience, PB plaster isn't going to do squat. I've run across similar situations with Hobie 17 dolphin striker posts. The issue is galvanic corrosion as stated above and the problem is that you end up with a 3-4" length where the post and compression sleeve seize together. The PB blaster is unlikely to penetrate the full length of the sleeve enough to loosen things up. Maybe if you have access to a 20 ton press or something you could press the striker post out of the sleeve. But most of us don't have access to that type of equipment. If you did, you would have to be certain the crossbar is properly supported or you would end up pushing both the sleeve and compression tube through the crossbar.

    The only thing I can think of (other than a press) that might work for your situation would be to use a hole saw to carefully enlarge either the top or bottom hole in the crossbar so that the hole matches the OD of the compression sleeve. The enlarged hole would allo you to slip the striker post and sleeve out of the crossbar as one piece.

    To re-assemble, you would need a custom compression sleeve and possibly a shim to take up the slop of the larger hole. This is essentially the way the Hobie crossbars are setup - the hole in the top of the crossbar matches the OD of the compression sleeve and the bottom hole of the crossbar matches the OD of the striker post. When the rod and sleeve seize together, you can just cut off the bottom nut and pull the whole assembly out through the top of the crossbar.

    sm
  • 2 thoughts. 1. drill out the ds rod on both sides starting with a pilot hole and getting progressively wider til you are at the rod thickness 2. Attach a hacksaw blade to a hockey stick and saw the thing in half inside the beam. Both are going to take a bit of time and patience but will get you there without damaging the beam.

    --
    Dave Bonin
    1981 Nacra 5.2 "Lucile"
    1986 Nacra 5.7 "Belle"
    Winnipeg, Manitoba, Canada
    --
  • Good luck going through a stainless rod with a saw blade on the end of a hockey stick! It would be like digging out of prison with a spoon. I wish I had a constructive alternative, but I wouldn't wish that task on my worst enemy.

    --
    Tom
    NACRA 5.7 (1984 Sail 181)
    Pennsylvania
    --
  • Agreed it sucks. Soak the crap out of it with penetrating oil for several days and try and knock it out with a pin punch first and pray.

    --
    Dave Bonin
    1981 Nacra 5.2 "Lucile"
    1986 Nacra 5.7 "Belle"
    Winnipeg, Manitoba, Canada
    --
  • First , cut off one end of the rod flush with the beam. Leave the other end appx 1" outside the beam.
    Second, soak it.
    Third, support the beam properly, then use a 9/16" shallow socket under one side, & attempt to drive the rod through. You can hammer pretty hard, The socket will support the beam & prevent the hole becoming pushed out. You will soon see if you can move the rod. If so great, keep going, if not...
    Go to your local tool place and buy 2 cobalt bits, one 1/4", the other same diameter as the hole. If you have access to a drill press, use it. If not, figure out how to support the beam with the flush end of the rod up. That 1" bit you left sticking out the other side? Lock onto it with vice grips, so the piece can't turn. Using centre punch, make a divot in the centre of the rod, then drill a 1/4" hole, you only need to drill it 1/4" deep. Have a buddy dribble lube on the bit, old motor oil, anything, to keep the cutting edge lubed & cooled. Now change to the larger bit, & drill down 1/4".
    Your DS rod will now only be held by the AL compression tube. Use a dremel tool with suitable attachment to reach slightly inside & grind/cut away the end of the AL tube.
    Lastly, using the vice grips, pull the end of the DS rod hard outwards, & cut off flush with beam.
    The remaining piece will now be loose inside the beam & will fall out the end. Depending on if you didn't quit drill 1/4" deep, you might have to run a hockey stick down inside, against the drilled end & knock it to one side till it turns enough to fall out.
    The DS rod is 316 SS, it will drill OK, with a cobalt bit. They are not much money either. Once you get set up to support the beam etc, you will do the entire job in less than an hour. It could be cut from the inside by taping one of those low profile hacksaws to a long piece of re-bar, then using a person at each end,
    https://www.amazon.com/St…RID=7DT03QH48515P9K553GT
    If you really want low tech, secure a heavy duty bastard mill file on edge to the mentioned re-bar,(I have one that weighs 2 lbs), get some beer, a friend, then pretend you are a Klondike Gold Rush miner in 1896, sawing boards for a boat.
    I have used all these methods at one time or another,(it was helpful as a kid, having a best buddy whose Dad was a driver/mechanic in WWII, & had a full machine shop on their 5000 acre ranch). but drilling is faster/easier.
    Decide first which you want to try. if you go file or hacksaw, DON'T cut the DS rod off. Leave stubs at each end, so you can secure it with V grips.



    Edited by Edchris177 on Oct 27, 2016 - 11:15 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
    --
  • Thanks for all the replies! I will try to soak it in penetrating oil and see if I can punch it out with the 9/16 socket supporting the sleeve. Most likely I will cut the DS rod and use the drill press method to progressively drill it out. The good thing is I have 7 months until the next catamaran sailing season in New Hampshire. The boat came with a really nice set of sails, so the PITA of dealing with corrosion may be the price I have to pay for the nice sails. This 5.7 is a 1994 and my 1987 5.0 is a fresh water boat and didn't have any of the corrosion issues.
  • Once you get it apart, be sure to coat the new striker post and sleeve in an anti-corrosion grease like Tef-gel.

    sm
  • I just saw this one and would suggest a couple of additional options. 1st try to soak the DS and the tube in CLR rather than oil, it seems to help break down the white oxide crust a bit. But I really think the following is is going to be your best option, 2) cut the DS as close to the main beam tube top and bottom then if you have a Dremel tool try to reduce the length of the remaining DS or at least get some bevel on one end of the rod. Then try to drive the DS both inward and slightly sideways into the beam taking advantage of the bevel you ground in. It may be possible to drive it far enough to totally break it loose, but if not and you can at least get the DS started angling into the main beam you can sort out how to get a doubled line around it and pull the line with it wrapped around the end of the DS that you drove into the tube. I think all of this could only be accomplished with the main beam off of the boat. If you distort the area around the DS hole some to do all of this, I think that would still be better than dealing with an enlarged hole because the aluminum will conform back when you put it all back together.

    It also occurs to me that with the super shortened DS rod cut as close to flush as possible that you could try to very very carefully ovalize the beam tube in a vise, or with some clamps giving you a bit more space to get the DS driven out of the beam. The trick here is to not actually permanently bend the beam tube, but to just make it flex and ovalize enough to get the DS remnant out. Getting the DS cut and ground as close to flush as possible top and bottom to the beam might make this approach work with the beam still on the boat. Apply the compression at 90° to the DS as possible. If your DS is cut flush to the tube you barely need 1/8" more to be able to drive it in and out I think you could get that much without permanantly distorting the beam tube. Having said that I would carefully test compressing the beam in this way to see what the results are. If a huge amount of force was getting appied with no significant movement stop and go on to plans D, C to Z.

    Remember to put some preload on the DS when you do put it all back together.

    dg

    --
    dg
    NACRA 5.2 #400
    This End Up
    Original owner since 1975
    --
  • Quote cut the DS as close to the main beam tube top and bottom then if you have a Dremel tool try to reduce the length of the remaining DS or at least get some bevel on one end of the rod.

    A dremel is a poor way to work a 9/16" SS rod, it just doesn't have enough omphh. A $6 cobalt bit will eat the material in a few minutes.
    To see how much you actually have to remove, cut a piece of 11/16" wood dowel, just long enough to slide into the beam, (9/16 for the DS rod + 1/16" on each side of the compression tube).
    Now start sanding, until you can twist the dowel from enough to have it come out...it will be surprising how much of a bevel you need.
    You could go with a bevel on each end, on opposite sides of the dowel, but drilling down 1/4" is way faster/easier.
    Once you cut the rod flush, you are out of options, there is no way to hold it to prevent spinning.
    Compressing the beam might be a good option, but I'm not sure if they will spring back. I know if you suck down the beam straps without end caps in place, the tramp slot gets compressed, & doesn't pop back.
    I have a few spare beams, I'll try it in a vise & see if it will revert to original shape.

    --
    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
    --
  • I agree about the Dremel, a die grinder and a burr would be much better, but probably not an available option. I suspect that drilling would be very problematic since it may be hard to stabilize the rod. It would be good to know in advance if the beam can be ovalized without damage.

    If none of these techniques work it may be worth the expense to see a machine shop. They may be able to enlarge just one side and then roll a washer to cover the enlarged hole. Just remember that that spreader/spacer tube is important it helps transfer big loads to both sides of the main beam. So don't be tempted to abandon it.

    --
    dg
    NACRA 5.2 #400
    This End Up
    Original owner since 1975
    --
  • Quote I suspect that drilling would be very problematic since it may be hard to stabilize the rod.

    That is why you DON'T cut the rod flush at both ends. Leaving one end long enough to be held in a vice makes drilling easy. After you progressively drill 1/4" into one end, cut the other flush & drop the inside piece out. There is no damage or elongations to the beam that need repair, the whole job should only be an hour once you have the 2 bits, & the beam off the boat.

    --
    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
    --
  • The cross bar was a challenge to take apart, as the PO used adhesive caulk to seal the cross bars to the decks. It took a while to get the caulk out of the cross bar, so I could slide the tramp off. Once the cross bar was off, I took it to the maintenance shop at work.

    I cut both ends of the bolt with a sawsall, the top about a 1/2" from the beam and the bottom about 1" and then used a drill press to drill the top of the bolt while vice grips held the bottom of the bolt. I drilled progressively from 1/4" to 1/2" and because the bolt was not held tightly, the bit wandered so that there was no bolt on one side and about an 1/8" on the other.

    http://morsephoto.com/squamcat/nacra57-ds1.jpg

    Then I took the dremel tool with a cutoff wheel and ground down the rest of the bolt. I made a couple nicks in the crossbar, but not too bad. Once the bolt and sleeve were ground down and inside the cross bar, I took a hack saw and cut the other side of the bolt and knocked it out with the hockey stick.

    http://morsephoto.com/squamcat/nacra57-ds2.jpg

    Once I get the new compression sleeve from Murrays, I can start to put it all back together. I am sure it will be tricky to get the sleeve lined up, but should be easy after that.

    My old Trac 16 had a slot in the trampoline track on the cross bar, so you could take the tramp off without removing the cross bar. I am surprised that Nacra didn't do this. It would be a nice option when storing the boat outside in winter.

    Thanks again for all the support! It is great to have a network of cat sailors to learn from.



    Edited by SquamCat on Oct 29, 2016 - 12:38 PM.
  • QuoteMy old Trac 16 had a slot in the trampoline track on the cross bar, so you could take the tramp off without removing the cross bar.

    That is one of the few things I prefer on the H18 vs the N5.7. For winter storage I just undo the 4 front beam strap bolts, pull the tramp out, & roll it around the beam & take inside. I have some spare beams, I loosely mount one to keep the platform ridgid.
    Quote I am sure it will be tricky to get the sleeve lined up, but should be easy after that.

    Easy job, but you need a helper. Tape the sleeve to the end of the hockey stick & insert in beam. Push a bent twig through to hold it there, then assemble the DS rod & V brace strap. like this;
    http://www.thebeachcats.c…pictures?g2_itemId=73301
    Make sure the threads on the DS rod are clean, even use a couple drops of oil. if there is any resistance SS has a nasty habit of cold welding itself.

    --
    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
    --
  • Glad you got it out!

    Notice that in Canada there are 101 uses for a hockey stick and tape. We all have half a dozen lying about so whenever there is a need... My dad stakes his tomato plants with them.

    I have 3 right now and I don't even like or play hockey.



    Edited by Wolfman on Oct 29, 2016 - 01:42 PM.

    --
    Dave Bonin
    1981 Nacra 5.2 "Lucile"
    1986 Nacra 5.7 "Belle"
    Winnipeg, Manitoba, Canada
    --

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