I tried the search on this site=no matches

Training for the Gr. TX Cat Race, my 2nd year to do it, off shore we broke the rear, port ,aft, inboard cross bar bolt. You know, the one that holds the strap bracket on the rear crossbar. It looks like a special bolt, my mechanic ground crew says it's zinc.

I've heard of a 6.0 in the Tybee 500 breaking some cross bar bolts also.

I'm just beginning my search, it happened yesterday. If you know first hand what I need, and if I should be replacing all of them, I'd appreciate it.

I have about 10 days to get them.

Thanks,
Todd Bouton
N 6.0 na +
Gr. TX team TCDYDIII
cell 713-305-6685

Hi Todd
Sail hard ,-as Team Castrol used to say ,-during the G T race ,-best of luck in it .
Team Morada did pop off a rear bolt on the crossbeam in this years Tybee 500 ,-it is fairly common on the 6/0 with added larger spin adaptation placing added loads and increasing the racking tortion aspect of 2 hulls working independantly through waves along with the stress of sail loads.--The distance on design of the 6/0 ---originally a 5/8 stretched out to 6/0 meters --from front crossbeam to bow adds to the racking leverage .

I did the same in the 99 W-1000 race ,-popping the rear outside bolt on the 6/0 -then raced with Smyth spin of 450 sq ft ,placing evan larger loads on it ...
The only way we finished the leg with about 40 miles to go was to take the spin down ,-then we used the trap wire and cinched it to the rear foot strap which held the boat together from mast leverage while we babied it in to the leg finish .-It would have been better to the trannsom gudeon --but the foot strap miraculasly held.

The leading active 6/0 racing expert on the6/0 is Rick Bliss at N E CATAMARAN . Rick raced the Tybee 500 last year .I recommend contacting him and asking advise on this and any other aspect of distance racing you may have .

I recall in the early 1000 mile races also a highly modified 6/0 by Smyth ,-he recognized the problem and added a center bolt with reinforcing up through the hull inside the rear beam with a semi-circular washer type fitting with bolt and lock washers over --the interior hull in that area would have to be reinforced as well and loads spread out .

--The only other suggestion I might make is going to the 270 sq ft spin that the I-20 uses .-
It has a more forward block lead placement that takes the pull away from the back beam and helps reduce racking stress caused by larger spin with aft block location .

In the higher winds of the G T race the smaller kite will be more managable and the ability to reach with spin more may be a good trade off with the 270 sq ft spin rather than 348 sq ft aft lead version.

Hope that is helpfull
Carl

Carl,

#1. I've been using an I-20 spin, on my Nacra 6.0 for years, and will in the GT race, like last year.

#2. Thanks for the history, but I need type of bolt, etc. The manual says it's a 2x5/16" bolt, but the one I have that snapped, looks like it has a different core inside, as I said, my diesel machanic/ground crew, says it's a zinc coated bolt. I bought my boat from a guy with a rigging shop on Clear Lake, he may he changed them, I"m trying to contact him also.

Todd - order a bolt from Performance catamarans or you should be able to get everything you need from the code stamped on the head of the bolt. Get the code information and look it up on the internet.

I highly doubt they are zinc or even zinc plated. If you see a different texture on the inside of the point of fracture - it's probably only because of the different stresses associated with it's failure. It probably was first cracked from repeated stress over a long time and what was left finally gave way - the two different failures will look differently in the cross section.

You may also be able to upgrade to a harder bolt but you are probably better off just replacing them periodically or finding a way to attach the spinnaker block to the hull just in front of the rear beam to locate the stresses directly on the hull instead of going through the beam and attachment strap first.

Jake,
Thanks, I'll look into the bolts more tomorrow.

Carl was talking about a rear crossbar mounted spin, and interestingly enough, advised on the spin I've been using.
I guess Carl thought that was why one of my crossbar bolts failed.

Jake, you been around for awhile, and If you thought about it, you'd realize that my spin does not sheet to the rear beam. The first block, a Harkey Ratchamatic, is on the shroud base, via a shackle.

Sorry Todd...I was just involved in a speed reading accident.

Sorry to hear about the failure. Glad you made it back to shore OK.

Now didn't I warn you about those bolts a week ago?

Chris.

Todd,

Step back for a second. Those bolts are suppose to be SS 304 or preferrablly 316. The real question is did you strip the threads. Then you need to retap and upsize the bolts or use a helo coil repair. Retap is simplier. Those bolts are threaded into an aluminium backing plate in the glass. If this is damaged or you want to increase comfort you may want to add a lock nut to the rear strap bolts. An additional through bolt into the inside of the tube like the front crossbeam may give some comfort.



Good luck.

Yes Captain Chris,

You did warn me, I mentioned that several times, before and after it happened. We eased up and by the time we were near surfside, we were again fully trimmed, as the wind had fallen off at that point. Where OUr ground crew was waiting. I didn't want to continue on and loose a hull off the crossbar.

Apparently, Ian and Dave had some shroud problems, I don't know the details, but I heard they made it to Cat Alley well before sundown.

eVileen woodhead sped reeding corses -ditto

Sorry Todd --should have read it completely and noted the added line of 6/0 with 270 sq ft kite ,--its been years since racing the 6/0 -mine was with a 450 sq ft Smyth spin on a 15 ft spin pole sheeted to the rear crossbeam .

Jake {engineer } and spin mistro par excellence ,-has good advice on stainless stl. bolts ---
-also the added center through bolt up into the center of the rear crossbeam with a semi-circular base that contours to the circular crossbeam diameter with lock washers etc and internal hull reinforcing is the solution Smyth used in the 98 W-1000 --sometimes {history} and looking back to find a practical solution that worked well is usefull.

best of luck in the G T race --
Would like to see some take the 6/0 set up one step further and not only adapt the Inter-20 spin size -spin block location and set up and also use the I-20 C F mast and sail plan plus rig ,--it is a larger main --much lighter mast -and would increase speed on all points of sail .--Some would bring up the balance aspect of CLR vs CSA --CENTER OF LATERAL RESISTANCE -CENTER OF SAIL AREA -relationship --the I20 rig with larger sq top main and smaller jib has a further aft center ,-the added componant then may be just as the I-20 recently changed to --add a larger rudder ,--or also switch to the larger lighter new I-20 rudder system ,-that would add more underwater lateral resistance area aft to help balance the new added sail area .-

The I-20 sail plan and new rudders on Nacra 6/0 platform
would be faster than the 6/0 NA W spin ,--and equal to the I-20 or potentially a tiny bit faster in waves and choppy sea conditions ,-the I-20 may still have the advantage in hull speed potential in flat water or more overpowered high wind conditions .-

Perhaps the improved rig and sail plan equvilant to the I-20 that has been adopted in lesser form to Hobie 20s w sq top main w spin --the P-19 X W sq top and spin -and other 20s to follow is the next evolution for 6/0s and numerous other 20s .

CDR