Hobie Forums :: View topic - Setup problem. Did the arc on the front crossbar change?

No changes to the bend dimension, but it is adjustable at the striker rod. Maybe someone tightened it on the newer boat? Flatter is faster it seems.

The 84 would have still had the longer shrouds, maybe that is why you are having difficulty connecting.

But as for the difference in the crossbar arc I can't help you there. All my boats are right around the 82-87 range and all their cross bars seem the same.

Bend specification is measured from the lower edges of the beam which is inside the casting, so hard to do when assembled. It says 4 1/4" to the underside of the beam.

Striker spec says tighten until not loose... then turn nuts "four flats" (about a half turn I guess) on both sides. Just slightly tighter than loose.

Racers found that the flatter beam allows the outer sides of the hulls to be more perpendicular to the water... Better lateral resistance. That would be to a point... then the bows are splayed out to wide.

Maybe this would work to check... I have a measurement from the back sides of the posts, on center... measure the distance between the forwards and then rears.

78 1/2" front

77 1/4" rear

The Hobie 16 is very hard to measure... very asymmetrical, so just to compare to the other boat.

Have you raised the mast yet to see if that changed the length of the main so it went back the way your other boat was?

Hmmm
Is was told by a racer (to remain unnamed), that the racers from PR (to remain unnamed) told him the first thing they do with a new boat is make certain this fore and aft, pylon to pylon measurement is the same.
"Keep the hulls parallel with one another"
I damn near galled the rod/nutz on mine attempting to do this :roll:

Author:	SlowSL [ Thu Aug 08, 2019 5:06 am ]
Post subject:	Setup problem. Did the arc on the front crossbar change?
I recently purchased an '84 in order to replace my '72. I had new parts on the '72 so I just swapped them over to the newer boat, however the forestay takes some extreme effort to reach the top hole of the adjuster plate, even with two plates pinned together for extra length. On the old boat, I had installed the newer style shorter side shrouds, and had ground the step to accept the extra rake. Instead of buying the longer bridle wires, I pinned a 2nd adjuster plate to the front, and was always really easy to pin the forestay. The shrouds, mast, bridle wires, and double adjuster plate all moved over to the new boat. I've been scratching my head trying to figure out what is different between the two boats, afterall, all of the standing rigging moved over from the old boat. I'm pretty sure the front crossbar on the new boat arcs quite a bit higher than the front crossbar from the '72. Just looking at it, from my memory, the crossbar from the '72 barely had an arc to it. I would assume once the mast step changed around 1982, in order to get some elevation on the boom, the front crossbar arc may have been increased to bring everything up a bit. I don't currently have access to the old boat to compare. Am I correct?

Author:	A1cnc [ Thu Aug 08, 2019 7:25 am ]
Post subject:	Re: Setup problem. Did the arc on the front crossbar change
The 84 would have still had the longer shrouds, maybe that is why you are having difficulty connecting. But as for the difference in the crossbar arc I can't help you there. All my boats are right around the 82-87 range and all their cross bars seem the same.

Author:	mmiller [ Thu Aug 08, 2019 8:13 am ]
Post subject:	Re: Setup problem. Did the arc on the front crossbar change
No changes to the bend dimension, but it is adjustable at the striker rod. Maybe someone tightened it on the newer boat? Flatter is faster it seems.

Author:	SlowSL [ Thu Aug 08, 2019 8:40 am ]
Post subject:	Re: Setup problem. Did the arc on the front crossbar change
mmiller wrote: No changes to the bend dimension, but it is adjustable at the striker rod. Maybe someone tightened it on the newer boat? Flatter is faster it seems. I had no clue enough tension could be applied to the rod to bring the crossbar arc up. Maybe that's the problem, it is way way up there, looks kind of silly, but just thought that was the way it was supposed to look. I will see if I can back off the tension and bring it down a bit. Is there any type of guide to set the tension properly?

Author:	SlowSL [ Thu Aug 08, 2019 8:52 am ]
Post subject:	Re: Setup problem. Did the arc on the front crossbar change
A1cnc wrote: The 84 would have still had the longer shrouds, maybe that is why you are having difficulty connecting. But as for the difference in the crossbar arc I can't help you there. All my boats are right around the 82-87 range and all their cross bars seem the same. Well, that would normally be the case with the shrouds, but I've added an extension to the front so that it could reach easily. It worked perfect on my old boat, and like I said, every bit of the standing rigging, jib halyard, and mast moved to the newer boat frame. Only difference I can see is the arc on the front crossbar. As Matt said, it may be tensioned very tight. I will mess with it when I get home. Here is a photo of it.... the arc is not as pronounced in the image, but in person, from a side view, it is pretty high.

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Setup problem. Did the arc on the front crossbar change? http://www.hobie.com/au/en/forums/viewtopic.php?f=14&t=65346	Page 1 of 2

Author:	mmiller [ Thu Aug 08, 2019 9:50 am ]
Post subject:	Re: Setup problem. Did the arc on the front crossbar change
Bend specification is measured from the lower edges of the beam which is inside the casting, so hard to do when assembled. It says 4 1/4" to the underside of the beam. Striker spec says tighten until not loose... then turn nuts "four flats" (about a half turn I guess) on both sides. Just slightly tighter than loose. Racers found that the flatter beam allows the outer sides of the hulls to be more perpendicular to the water... Better lateral resistance. That would be to a point... then the bows are splayed out to wide. Maybe this would work to check... I have a measurement from the back sides of the posts, on center... measure the distance between the forwards and then rears. 78 1/2" front 77 1/4" rear

Author:	SlowSL [ Thu Aug 08, 2019 10:20 am ]
Post subject:	Re: Setup problem. Did the arc on the front crossbar change
mmiller wrote: Bend specification is measured from the lower edges of the beam which is inside the casting, so hard to do when assembled. It says 4 1/4" to the underside of the beam. Striker spec says tighten until not loose... then turn nuts "four flats" (about a half turn I guess) on both sides. Just slightly tighter than loose. Racers found that the flatter beam allows the outer sides of the hulls to be more perpendicular to the water... Better lateral resistance. That would be to a point... then the bows are splayed out to wide. Maybe this would work to check... I have a measurement from the back sides of the posts, on center... measure the distance between the forwards and then rears. 78 1/2" front 77 1/4" rear This gives me a reference to start with. I will measure at the posts and see if I can match the given measurements. I should probably measure the bottoms of the hulls (center to center) at the bows, stern, and midway to see how close they compare. My fear is that it has been tensioned so far that it is beyond the crossbars ability to spring back the needed amount, but I guess I will see. Thank for all the info!

Author:	mmiller [ Fri Aug 09, 2019 8:27 am ]
Post subject:	Re: Setup problem. Did the arc on the front crossbar change
The Hobie 16 is very hard to measure... very asymmetrical, so just to compare to the other boat.

Author:	SlowSL [ Fri Aug 09, 2019 9:00 am ]
Post subject:	Re: Setup problem. Did the arc on the front crossbar change
mmiller wrote: The Hobie 16 is very hard to measure... very asymmetrical, so just to compare to the other boat. Okay, I'm under the assumption the point along the bottom of the hulls would remain parallel. I didn't have a lot of time to mess with it last night, but the striker rod was not all that tight. I loosened it all the way, the crossbar didn't budge, so I just snugged it back up. There is a little fore/aft movement with the striker rod and bar, but that should be normal from what I've read. I'm still going to measure just to make sure the front of the hulls are not pulled way in, but it's looking like I'm stuck with it this way. I'm going to try to compare the other crossbar over the weekend and see if any difference can be measured. I made a longer extension for the front in order to pin the shroud easier. Once I had the sails up, rig tensioned, and side shrouds adjusted, there was no problem getting the main close to block to block, and appears to have decent rake, so I think I'm all good. On a side note, one thing I did notice last night was a slight bulge to the outside at the rear starboard hull, but I think it may be okay. I'm no expert on the hull fabrication, but it looks like it's all still connected as it should be. I grabbed the rear crossbar and rocked side to side pretty hard, and could hear a faint thud near the area, might just be the foam clunking. I piped an endoscope in the drain plug to take a better look. I did notice one piece of frayed out fiberglass along the shoe/hull in one spot, but all of the fiberglass looked well connected between the pylon/shoe and the shoe/hull. I will start a new thread on that and provide a video later.

Author:	SlowSL [ Sat Aug 10, 2019 1:12 pm ]
Post subject:	Re: Setup problem. Did the arc on the front crossbar change
I just measured 77-1/4" front, 77" rear. Tried to measure as best that I could on the arc height, but looks to be about 4-3/4", maybe a bit more. I'm taking it off to see maybe if I can flatten it out a bit, this is probably going to end badly. I also noticed the striker bar nuts were nearly turned all the way to the end of the threads, so It had been cranked in hard all these years.

Author:	SlowSL [ Sat Aug 10, 2019 9:38 pm ]
Post subject:	Re: Setup problem. Did the arc on the front crossbar change
I ended up shimming the pylons, so while I had the frame off, I successfully straightened the crossbar. I propped up the front with 2x4's under the corner castings so the striker bar was off the ground. I backed off striker bar nuts most of the way. Then I jumped up and down on the crossbar like a lunatic until I could see that the corner castings moved out enough that they were touching the nuts. I reassembled and re-measured, and the distance is now within spec.

Author:	A1cnc [ Sun Aug 11, 2019 8:03 am ]
Post subject:	Re: Setup problem. Did the arc on the front crossbar change
Have you raised the mast yet to see if that changed the length of the main so it went back the way your other boat was?

Author:	SlowSL [ Sun Aug 11, 2019 11:57 am ]
Post subject:	Re: Setup problem. Did the arc on the front crossbar change
A1cnc wrote: Have you raised the mast yet to see if that changed the length of the main so it went back the way your other boat was? No, not yet, I will post the results when I do. I know on the old boat the side shrouds were pinned 3rd from the bottom hole to attain near block to block. Before straightening the crossbar, it was the 6th hole from bottom.

Author:	flatlander [ Mon Aug 12, 2019 9:58 am ]
Post subject:	Re: Setup problem. Did the arc on the front crossbar change
mmiller wrote: Bend specification is measured from the lower edges of the beam which is inside the casting, so hard to do when assembled. It says 4 1/4" to the underside of the beam. Striker spec says tighten until not loose... then turn nuts "four flats" (about a half turn I guess) on both sides. Just slightly tighter than loose. Racers found that the flatter beam allows the outer sides of the hulls to be more perpendicular to the water... Better lateral resistance. That would be to a point... then the bows are splayed out to wide. Maybe this would work to check... I have a measurement from the back sides of the posts, on center... measure the distance between the forwards and then rears. 78 1/2" front 77 1/4" rear Hmmm Is was told by a racer (to remain unnamed), that the racers from PR (to remain unnamed) told him the first thing they do with a new boat is make certain this fore and aft, pylon to pylon measurement is the same. "Keep the hulls parallel with one another" I damn near galled the rod/nutz on mine attempting to do this

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Author:	SlowSL [ Mon Aug 12, 2019 10:29 am ]
Post subject:	Re: Setup problem. Did the arc on the front crossbar change
Quote: Hmmm Is was told by a racer (to remain unnamed), that the racers from PR (to remain unnamed) told him the first thing they do with a new boat is make certain this fore and aft, pylon to pylon measurement is the same. "Keep the hulls parallel with one another" I damn near galled the rod/nutz on mine attempting to do this As Matt said, the measurements are not the same. This doesn't mean that the hulls are off, just means that the pylon/casting geometry was not designed to be identical, but the hulls will still be parallel. Were they trying to get the flat sides of the hulls parallel, or the hull toe in/out straight? My hulls were toed in pretty far with the front crossbar drawn in tight, I would guess that would produce a ton of drag.