Replacement Front Crossbar Mismatch Woes

I need your thoughts on a confounding problem that I am having with my front crossbar.

I took the front bar off to investigate a water leak and discovered significant corrosion in the crossbar on each side where the hull bolts attach. I purchased a used replacement front crossbar from a dealer, but when I went to install the bar it didn't fit -- it appeared to be hyper-arced and clearly did not lay flat on the hulls. The arc difference was readily evident when the two bars were superimposed on top of each other. I sent pictures to my regional Hobie dealer who spoke with the Hobie gurus out in California, and they advised me to not install the replacement crossbar because they feared that it would damage the boat, but advised me to get another crossbar. So that's what I did. And guess what? The 2nd replacement crossbar is exactly the same shape as the first replacement crossbar I received. This must mean that my original bar is abnormally under-arced, and that the rear crossbar must also be under-arced given that my original front bar fits perfectly.

My boat is a 1998 that is in pristine condition. It has been housed in a boat barn its entire life, and the hulls are in no way warped that would account for the misfitting crossbar. The crossbar is visibly undamaged except for the previously mentioned corrosion.

Does anyone have any experience or insight regarding misshapen crossbars? The only thing I can think of is that my crossbars (front and back) came as a set that is unique to my boat. Have you heard of such a thing?

The solution to the problem as I see it is to purchase a replacement rear crossbar that I know matches the replacement front bar. Presumably (and hopefully!) the replacement rear crossbar will also be hyper-arced with respect to my existing one, and both will fit snugly in place.

Thanks for you thoughts!

I've been messing about with H-18's since 1980, and I have never heard of such a thing. The only change, that I am aware of, to the front crossbar was the mast step went from 2 rivets to 4 rivets.

Can you also send me a picture, possibly I may be able to figure out what might be going on, but from the way you have described it, at this point I am clueless.

My E-Mail MUST429(at)aol(dot)com

Stephen

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If the grass is greener on the other side of the fence, maybe it is time to water your own lawn.

My first thought is that if your front bar was corroded then the back most likely is as well. I have seen the rear damage on 2 boats with no damage to the front. Do the replacement bars have the dolphin striker attached and tensioned? This could be the issue but its unlikely. Are these replacements new or used? The cant on the boats should be the same from year to year so any years bar should fit the same. Perhaps as the front was deteriorating it allowed the rear to bend, again not likely. Any pics of the bars and how they fit?

Here is my crossbar problem, illustrated:

http://www.flickr.com/photos/29360489@N07/2742364789/
http://www.flickr.com/photos/29360489@N07/2743201558/
http://www.flickr.com/photos/29360489@N07/2743201934/
http://www.flickr.com/photos/29360489@N07/2742364897/

Thanks.

Sorry if I'm stating the obvious, but there's no striker on the old one. You probably removed it in dis assembly but it and the cantilever stays cannot be the same length as the new ones. Geometry won't allow it.

If it wasn't there then your crossbars probably did flatten out considerably over the years. Those parts are integral to the design. Without them the crossbar(s) would have no resistance to the considerable downward force that the mast would apply not just from it's weight but from the forces that the sails and stays apply. If that's the case I'd be glad they didn't fail.

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The ox is slow but the earth is patient

Without knowing any more than you have written here, and now, seeing the pictures, I have to agree with JS, it appears that for whatever reason your old crossbar has flattened out. The new one does indeed look correct, and if the rear one has flattened also, then you should probably replace it at the same time. Trying to use the new front without correcting the same problem in the rear crossbar woud create MUCH larger problems, by stressing the fiberglass @ the mounting points.

One way to try and tell if the hulls are in the correct "attitude" would be to put in just the rudder pins, without the rudders, and then,very carefully measure the distance between the rudderpins, both at the top and the bottom. The measurement should be identical. If the measurement shows the hulls are toed out at the bottom, I'd say it is a fair bet your should also replace the rear crossbar.

Keep us appraised of your progress. I wanna know how the story ends.

Stephen

_________________
If the grass is greener on the other side of the fence, maybe it is time to water your own lawn.

I have the same question. In the pics it appears the boat was used without the dolphin striker as there is no wear on the hulls, is this correct? Your rear bar does appear flatter than it should. Are the striker bolts tight on the replacement bar? They should have the tension released before fitting to the boat. Your fit in the pics is not perfect but can be worked around, my concern is that the rear bar is compromised as well. Have you checked around the bolt holes for cracks on the rear bar? It may be hidden damage. Also, it may help to loosen the rear and fit the front and rear at the same time so one isn't fighting the other.

No idea who they spoke with here at Hobie (not me), but my opinion is that the old bar was flattened by use and a slack striker system. Now the rear bar may have taken a similar set.

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Matt Miller
Former - Director of Parts and Accessory Sales
Warranty and Technical Support
Hobie Cat USA
(Retired 11/7/2022)

I happen to be working on an 18 today and took a quick measurement that may help you diagnose your problem. There is some variation from boat to boat, but I measured 80.5" (port to stbd) from the centerline of each board while half way down, both at the top and bottom. Again, there will be some variation, but I suspect that yours would measure something like 75" at the top and 85" at the bottom center to center with your old X bars.

Can't wait to hear the story of your boat. It's an interesting situation.

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That would be quite a sight to see a Hobie 18 sail without a dolphin striker assembly, or should I say, watch it split asunder under the influence of the first heavy wind! No, the pictures submitting are of the crossbars with the dolphin striker assembly removed from the old bar and placed on the new bar, without tension.

To clarify, the posted pictures are of the front crossbar only, not the rear bar. They compare the lie of the bars sitting atop the boat, unbolted. The pictures of the superimposed bars compare the two front bars, not the front and rear. For further reference, below are two more pictures of the boat head-on, again with the original and new bars simply sitting atop the hulls:


http://www.flickr.com/photos/29360489@N07/2743201478/
http://www.flickr.com/photos/29360489@N07/2742364751/

Surf City and MUST 5429, excellent thought to compare the hull pitch by measuring top and bottom of a vertical reference. Will measure and let you know.

Yes, I agree with the supposition that my front and rear bars must have flattened out over the years. I have a replacement rear bar on order and will let you know how things turn out.

Thanks again for your insightful comments.

Indy

I am not sure what the factory recommended correct procedure for "beaming up" the Hobie 18 might be.

The procedure is best done with two people, but if you can support the hulls so that they don't roll over, you can do it alone.

The way I do it is to get the outer bolts in one hull, and thread the nut on just far enough to engage the nulock portion of the nut. Then while it is still easy to wiggle the crossbar around, get the inside bolt started being VERY VERY Careful not to cross thread it as it goes in, spin that one in till it is just barely starting to get snug. Then, place the other hull under the beams and do the same thing. Once all four inner bolts are just barely snug, tighten the outer 4 until they are also just barely snug.

Then measure across from corner to corner and make sure the hulls are squared up. you may have to wiggle them around a bit to get it squared up. Usually I can get mine to within an inch of being perfectly square.

Then tighten the bolts a little more, starting with the inners and ending with the outers. Then go around one more time, and put a final snug on all 8 once again starting with the inners and ending with the outers.

Be careful not to overtighten them, remember you are dealing with fiberglass. As someone that repaired cars for a living for 30 years, I have to be careful not to over tighten bolts on boats. I put German Torque on the bolts. that is to say Gutentight. Trying to explain relative tightness online is a bit difficult as your definition of gutentight might be a bit different than mine, but i'll try. Hold the wrench or the rachet about halfway from the end and give it a really good snug. If you hold it at the outer end, you can definitly overtighten. Another way to tell if you are overdoing it is if you hear fiberglass crunching.

As far as tightening the nut on the end of the rod that supports the Dolphin Striker, I tighten it till there is no play at the base of the dolphin striker, and then give each nut another full turn. The idea being that the rod should actually support the dolphin striker and the curve of the front beam without putting undue upwards pressure on the dolphin striker.

I hope that the above doesn't read like gobbeldy gook and gives you some helpful guidance.

Stephen

_________________
If the grass is greener on the other side of the fence, maybe it is time to water your own lawn.

When you get all this figured out and since you'll have the boat all apart any way you might consider "bedding" your cross bars. I did this on mine and it stiffened up the boat a fair amount.

I scuff sanded the hull beds, mixed up some MarineTex (I think... the white marine "Bondo" should do the same thing), vasaline'd up the cross bar and bolted it down.

Make sure you have everything ready to go because it set's in about 5-6 minutes...

My 2 cents...

BJ

In your first post you said you were working with a 98 in pristine condition.

I wouldn't even consider bedding your crossbars on hulls that new that are in good condtion.

Bedding shouldn't be necessary, and in my opinion, if you were selling, and I were an interested buyer, it couild, devalue the boat to some degree. It would cause me to wonder WHY it had been necessary, because it is so rarely done.
(I've had beams off of 30 or more 18's and have never seen it done or felt it necessary to do it to one I was rebuilding)

It would make great sense on an older boat or a boat that has a stiffness problem, but shouldn't be necessary or desireable on hulls that new unless they show signs of a lot of chafing or wear in the "bedded" area's.

Just my opinion ..... take it with a grain of salt, you might like his idea better.

Stephen

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If the grass is greener on the other side of the fence, maybe it is time to water your own lawn.

I'm with Stephen on this one. I wouldn't consider that on a '98 18. My old '81 doesn't even need it.

I find framing up the boat is most easily done with the hulls on the trailer. I use a small tie-down belt strapped around the hull and down to the trailer to hold each hull upright. With the hulls on the trailer, you've already got the correct approximate spacing, and you don't have to worry about getting the boat up on the trailer when you're done - it's already there!

sm