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PostPosted: Thu Sep 15, 2005 11:18 am 
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In teh H16 forum they were talking about how to tighten thier tramps. Most of the suggestions for really cranking on them were to prebend the side rails. Also for the rear grommits you start off in teh corner casting with a figure eight knot.

On the H18 you really don't want to prebend your hulls and the starter hole for the rear laces is in the deck lip.

So, how much can you tighten the tramp without causing damage to your hulls for both the center and rear lacings. And is the tramp tension as critical on the 18 vs the 16 since the structure of the boat is different?

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 Post subject: A matter of preference
PostPosted: Thu Sep 15, 2005 2:29 pm 
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In my opinion on the 18 the tramp is really not part of the strucural stiffness as it is on the 14/16. There for tightness is more a matter of personal preference. Obvious to loose and you catch a lot of waves under the tramp. With this problem you can feel the boat decelerate. As for how tight until something breaks...beats me. I like my tramp as tight as I can get it, but I don't use any mechanicle advantages when tightening.

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 Post subject: No Pylons - No Problem
PostPosted: Thu Sep 15, 2005 3:01 pm 
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The tight tramp is more of a comfort level thing with the 18 because the crossbars are connected directly to the hull. Same with the 17. Because the tramp "floats" on stanchions or pylons or whatever we call them, it is "separate" from the boat itself on a 14/16.

That's my story and I'm sticking to it 8)

Have a good one Nick!!
Time to go get a little tight myself :wink:

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 Post subject:
PostPosted: Thu Sep 15, 2005 8:07 pm 
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Location: Clinton Lake Lawrence, KS
Maybe I'm too 'old school" but just as with the 16, I believe hull stiffness is important and want a stiff platform.
This makes the basis for a fast and responsive boat.
Think of all the tension we're dealing with in the rig!

We tighten the inboard and outboard crossbar to hull bolts and tighthen the trampoline, using mechanical advantage, and the bridle anchors, before every sail. We trailer launch or I would check and tighten the dolphin striker rod every time, so it doesn't get done as often as I would like. Our average sail is four to six hours and I can't remember the last time any bolts didn't need at least a little tightening.

I religiously kept the 16 "tight as banjo string", raced it, thrashed it, dumped it, pitchpoled it and never cracked a corner casting, never had a loose pylon, and never developed the deck soft spot in front of a hull.

We feel the 18 is like a hotrod, and it sure performs like one. :lol:

I'd be sick if I broke it and thought there was a way we could have prevented it. :cry:

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 Post subject:
PostPosted: Thu Sep 15, 2005 8:38 pm 
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And I also wanted to mention that our tramp looks like a reverse of the 16 siderbar bend, in that when as tight as possible, the gap between the side pieces is about an inch or two closer together in the center than the fore and aft.

Another mod I want to do is replace the single lacing line with two, low stretch lines.

I have not noticed any bending in the hulls but we'll certatinly check that out this weekend.

And, in trying to protect my "investment?", I would rather break a tramp than break a hull.

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 Post subject:
PostPosted: Fri Sep 16, 2005 5:46 am 
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John,

Are you saying that on an 18 the tramp tension makes a noticable difference to the stiffness of the baot? I can see that if the hull to crossbeam joints were not tight enough the tramp would help keep the whole boat square, but what does it really add?

I don't race (at least not yet) but I do like my boat to perform. My concern is that if I really crank on the tramp I will cause other problems with the boat. On the 16's you won't damage anything that can't be easily replaced.

Just trying to get a full understanding of the boat.

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'84 H16
'82 H18 Magnum
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 Post subject:
PostPosted: Fri Sep 16, 2005 8:07 am 
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Nick,

I am not John, but I will do my best to answer your questions about tramp effectiveness.

I have two 18s and I have raced both. My first 18 has a black mesh tramp that came with it when I purchased it. I can only imagine, but I believe that it may be the original tramp from 1981. :shock: It is in great shape and my wife was kind enough to re-stitch it about a year ago. :D When I reinstalled the tramp, I got it real snug on tightness. All of the crossbar-to-hull attaching points were super tight. With the tramp snug, if I lifted a hull at the tip of the bow, the other hull would start to come up with about six inches difference between them. This was even worse while on the water with wave action (about 10” difference). :?

When I purchased my second 18, a 1982 model, the tramp on it was a vinyl type, but it was completely shot. I removed the black mesh tramp from the first 18 and installed it on this boat. I got the tramp installed at about the same tightness as when it was on the 81. The hulls still had a difference, but not as dramatic as the 81 (about 3” difference on land, 6-8” on water). :x

About halfway through this racing season, I purchased a new white vinyl Hobie tramp and installed it onto the 82 model. This time I installed the tramp super tight. So tight in fact that when one of my daughters lays on it, it only sinks down about ½” and they weigh about 60 pounds. :wink: With this tightness, the hulls on land have no difference when lifting (lift one or the other and the opposite side comes up instantly). On the water there might be a difference of ½” to an inch.

Now on to performance. With the old black mesh tramp, we were not able to keep up with other newer 18s. My crew and I always resorted to the fact that we were just going to come in 3rd (if there were only 3 boats competing) or later. We actually did a little better when the black tramp was on the 82 model boat, but we still could not perform to the level as some other 18s. However, all of this changed with the new tramp. All we did was change the tramp. Weather conditions have been varying, but as far as I can tell we have sailed in many similar conditions as we did with the black mesh tramp. With the new super tight white vinyl tramp this boat kicks butt!

Out of the eight races we have had this season, we used the black tramp for the first four races and placed first in one race. :( The second four races we had the new tramp and have placed first in three of the four. 8) The one race where we didn’t place first my crew broke his hand and we had to DNC after the first race. :shock:

As for things to watch out for with a tramp super tight, we are constantly keeping an eye on the rivets holding the tramp track to the hulls. If these let go, hang on! We also inspect the tramp for nicks and cuts. If you have one, it will not take long for it to grow. Lastly, we keep a close eye on all of the grommets. We don’t need one pulling out while we are 10 miles offshore in a distance race.

Hopefully this will help.


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 Post subject: Good story
PostPosted: Fri Sep 16, 2005 8:39 am 
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That is an intersting story. I never thought the tramp would effect hull stiffnes on an 18. But clearly, it must. I think I will be buying a new tramp soon, and maybe some of those dodads that go in the track because I intend to get that sucker real tight for now on. Thanks for sharing your experience.

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 Post subject:
PostPosted: Fri Sep 16, 2005 8:57 am 
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I wouldn't have thought it either. Just our of curiosity, how snug are your bolts holding the crossbeams to the hulls? I would have thought the rigid, direct connection of the crossbeams and the hulls would keep everything tight.

But, as I think about it more, the tramp acts as a diagonal brace that helps keep the frame square. When I replace mine next year I will have to run a few expereiments.

Thanks for all the good info.

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Nick

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'74 Pearson 30
'84 H16
'82 H18 Magnum
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 Post subject:
PostPosted: Fri Sep 16, 2005 9:32 am 
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Nick, you hit it exactly, it's the diagonal bracing, which Mike also eluded to in raising one hull at a time. Ours is a mesh tramp that is not new but probably not original.

We've come within maybe 30 boat lengths of Mr. Sohn and crew (who are currently leading the Nationals) at the finish in three of four races and at one point had them actually covering us (I was flattered). He's sailing one of the last 18's ever made, we used our '82 main, a six to ten year old jib we've picked up, '89 and supposedly lighter hulls. Excuses? No. I'm certain skill and experience are most of those boat lengths! Less overall weight, new sails and a tight rig might account for six of them.

Nick I forgot, tighten the crossbar to hull bolts in this order; inboard fore, inboard aft, outboard aft, outboard fore and then check the dolphin striker rod. Inboard bolts are allen, outboard are hex head.

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PostPosted: Mon Sep 19, 2005 5:34 am 
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After a day of sailing, I find the crossbar bolts are slightly loose. I measure to make sure my hulls are straight and tighten those bolts before everyday of sailing and everytime I can get an 1/16 to 1/8 of a turn. It is kind of weird though, my last 18 those bolts were so corroded I couldn't get them off when I needed to. My dolphin striker has never loosened on me, but I do check it also.

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 Post subject:
PostPosted: Mon Sep 19, 2005 10:28 am 
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Thanks guys for the input. I am planning on stripping and repainting my hulls this winter. I will have the whole boat apart anyway so I can look into finding a way to keep the crossbeam bolts from loosening. I would hate to have to tighten them every few times I sail. Even though I don't race, now that I know about them loosening I will beccome anal about it.

You all wouldn't happen to know to what torque you tighten them?

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Nick

Current Boat
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'74 Pearson 30
'84 H16
'82 H18 Magnum
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 Post subject:
PostPosted: Mon Sep 19, 2005 12:18 pm 
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Hmmm, Nick you're always thinking. :)

I'd guess the torque you can get out of a 1/4" by 4" allen wrench to be about 40 lbs.. And with a 6" ratchet & hex socket a little more. That may be why our bolts are always loose!

In thinking about how tight... it's snug and a just a little more. I guess I'm a bit paranoid of really cranking the torque to a metal and fiberglass connection (especially 20 some odd year old glass).

I'll revert to the checking them everytime, a "pre-flight routine" and for me it is peace of mind.

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 Post subject:
PostPosted: Mon Sep 19, 2005 1:02 pm 
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One way to increase your torque on teh allen, and socket for that matter, is to use a 12" piece of schedule 40 pipe to extend the wrench. If the bolt screws into a metal plate that is molded into the glass, as long as the plate covers enough area you won't have a problem over torquing the bolt.

Another thing to help with this woudl be to put a lock washer on these bolts to preload them so they will be less inclined to work loose. Now you all have me thinking way too much about this.

I think this is why the tight tramp seems to help so much. It makes up for any slightly loose bolts by preloading them so the nuts don't work themselves any looser.

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Nick

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'74 Pearson 30
'84 H16
'82 H18 Magnum
St. Louis, MO


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 Post subject: My torque
PostPosted: Mon Sep 19, 2005 2:15 pm 
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I agree with the previous post on how much torque. I too don't want to crank down on them and crack the glass. I guess checking them may be over protective but once you have seen one come apart with in mid air you start thinking about these things. Its the old theory, an once of prevention is worth a pound of cure.

Collin

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