Genoa tracks

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Postby Guest » Fri May 11, 2001 9:28 pm

I have only class sails. Need genoa to stay competetive in PHRF. Anyone have advice on location and installation of genoa tracks? What size? Where to locate them on deck? How to install? Etc?
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Postby Guest » Sat May 12, 2001 4:04 am

Dear Michael,
have a look at the Racing Tool and Technics heading and go for PHRF. 135 % seems to be the favour of the month for you light winds. Funny reading that, I just added lead to my bulb so I can keep my boat upright. 80% Jib.

There is another article from Jay Lutz in there somewhere regarding location of the track.

Just go looking for it. you will find it somewhere.

Regards

Bob
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Postby Guest » Mon May 14, 2001 8:08 am

Mike

If you have in hand the "sheet" from J Boats indicating the placement of a three foot Genoa track bear in mind that this was developed with only the 150% Genoa in mind. When I installed track on my boat (261) I called Al Johnstone at J Boats and asked him to work out on the computer recommendations as to how far back and how far off centerline the lead car should be placed for the 135% I planned to use. I don't have the exact measurements to hand anymore but it was forward and closer to centerline as you would expect.
Using the information he gave me I intalled a four foot length of "racing" track (more holes) angled to be closer to centerline forward (per Al's recommendations for the 135%) but wider off centerline aft and long enough to accommodate a 150% should I later feel the need (wider off centerline to place the lead car where J boats says it should be for the 150%) Interestingly, it resulted in a track almost exactly parallel to the class jib track - starting about an inch aft and outboard of the jib track.
I'm no naval architect but it has worked perfectly for the 135% so far, which, as it turns out, is all the sail I needed for PHRF.
My boat will be at the Worlds so you, or anyone for that matter, please feel free to measure what I did but I would strongly suggest a call to Al for his suggestions.
No matter where you place them, the deck is cored. Proper installation, with track bolt holes back drilled oversize from below and filled with West epoxy then redrilled to size to prevent water penetration and later delamination, is a given.
Hope this helps
John
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Postby Guest » Mon Jun 11, 2001 1:34 pm

I followed the advice of John and Bob, and I got Jay Lutz to send me a diagram as well. The new tracks went in fine and work well. Thanks to all. During the installation, I took one of the bolts out of the factory-installed tracks to check for size, and I did not see any evidence of epoxy or over-drilling, as many have recommended. Does the factory drill an over-sized hole, fill it with epoxy, and then re-drill to the proper size? If not, should we be reinstalling the factory tracks?
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Postby Guest » Mon Jun 11, 2001 3:19 pm

TPI has not made a practice of overdrilling holes and filling them to prevent core damage. You will probably find only silicon sealant in the deck fitting holes. Put it on your project list to gradually go through every deck fitting and seal/bed the hardware properly. Otherwise, a wet core is inevitable.
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Postby Guest » Mon Jun 11, 2001 11:15 pm

Far be it from me to defend TPI, but... the practice of overdrilling and epoxy filling holes prior to hardware installation is almost strictly an aftermarket or full-bore custom builder practice. I am not aware of a single production boat builder that does this in the act of their standard construction method. It would more than triple the labor to install deck hardware, and the buying public would go ballistic at the impact on baseboat pricing. It IS a great practice, but shy of having a custom boat built for you and making that spec part of the agreement (and getting priced accordingly), or having an aftermarket service agency do this for you, don't expect to see it on any yacht.
Guest
 

Postby Guest » Mon Jul 30, 2001 7:09 pm

Well guys it finally dawned on me, after reading countless posts and private E mails regarding placement of Genoa tracks, to ask the designer.
So I recently sent a letter to Al Johnstone at J boats and asked: If the factory were to install a Genoa track designed to accommodate genoas from 135% to 155% on the J/80, how long would it be and where would it be placed? I enclose below his reply.


John,

I recommend that a genoa track for the J/80 intended for both 135 and up
to
a 155 genoa is located as follows: (This assumes a 12" genoa clew
height).

Front end of track: 155.5" from bow on center measured in a straight
line.
(not along centerline of boat).
Minimum length of track: 46"
Forward end of track off center: 28.5"
Aft end of track off center: 31.35"

The lead angle in this scenario is 9.0 deg for a 155 and 10.0 for the
130.
It is also possible to bring the track further inboard by up to 2" to
change
the lead angles to 8.5 deg and 9.5 deg respectively. Personally, I like
the
outboard position as this makes sailing the boat with a genoa a little
less
critical.

If the clew height of the genoa will be higher than then the track
should be
located a little further aft.

Keep in mind that this is a minimum length track. It's not a bad idea
to
have additional track forward and aft of this location to account for
variation in genoa design. Your length of 48" will add an additional 2"
and
can work. I think I'd spec a track another 6-12" longer and center this
over the above.

Sincerely,

Alan Johnstone
J/Boats, Inc.
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Postby Guest » Mon Jul 30, 2001 7:24 pm

Thank you John,
well researched.
Bob
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