Your local North loft should have the designs on file? North did lots of design work over a few years on J97s in the UK. Your C0/J0 sounds like a fantastic sail for the boat
J97 Tuning Hints
- Thread starter Slainte97
- Start date
No one really interested here in J/97 it seems. Well I will continue this as a documentation thread in any case for future reference.
I managed to install barbers for the sheets to be used with the code coming from the toggles at the shrouds, no problem. I also installed a bob stay by removing the U-bolt at the end of the sprit, replacing it with a huge ring and then drilling a hole in the bow at the bottom of the anchor locker. So far so good. I then decided to check it by stretching it using the halyard/tackline. Then I noticed the ring was coming up from the bowsprit regardless of how I adjusted the stop knot. Conclusion was that the sprit outhauler is stretching. It seems to be a 6-8mm polyester rope as a 2:1 configuration. Decided to swap and make it 4:1 at least for the high compression loads due to the bobstay. Easier said than done though as it seems that the end of the outhauler is attached in the front of the watertight laminated sprit box with the inspection hatch being in the back end. Any suggestions other than sawing a hole and installing a new hatch in the front part of the sprit box in order to be able to change the rope?
I managed to install barbers for the sheets to be used with the code coming from the toggles at the shrouds, no problem. I also installed a bob stay by removing the U-bolt at the end of the sprit, replacing it with a huge ring and then drilling a hole in the bow at the bottom of the anchor locker. So far so good. I then decided to check it by stretching it using the halyard/tackline. Then I noticed the ring was coming up from the bowsprit regardless of how I adjusted the stop knot. Conclusion was that the sprit outhauler is stretching. It seems to be a 6-8mm polyester rope as a 2:1 configuration. Decided to swap and make it 4:1 at least for the high compression loads due to the bobstay. Easier said than done though as it seems that the end of the outhauler is attached in the front of the watertight laminated sprit box with the inspection hatch being in the back end. Any suggestions other than sawing a hole and installing a new hatch in the front part of the sprit box in order to be able to change the rope?
I raced used to race a J122 and to get round the problem it used a 4:1 purchase (or 3:1 but I think it was standard on larger models?) and used a tapered SK78 line with cover coming into the cockpit but had a Spinlock XX clutch side mounted onto the back face of the coach roof with a large pad glassed in behind it. They had experienced the problem of pulling the cam cleat through the bulkhead. Rather than use a stop knot I would splice in a dog bone instead. Also what line are you using for the bobstay?
Yes, was considering to either increase purchase or install a clutch on port side of cabin (starboard has one for the tackline). SK78 6mm pure dyneema for the bobstay.
Still looking to here if there are other solutions than introducing a new clutch in order to change the outhauler rope?
I would extend the bowsprit fully and mark the sprit with a pen and repeat your experiment. Maybe a few marks at 5mm spacings to work out how much if anything the bowsprit is retracting. I have a feeling that it is the bobstay is stretching, if I understood your description correctly the bobstay dyneema also holds the ring the tackline goes through? I am more inclined to think that it is the bobstay that has the stretch in it. Knot, the rope itself, the splice for the ring, all areas that can stretch
IMR
Anarchist
Two things to think about the bob stay will stretch unless you use something like pbo, but then uv will kill it. We have had success with heat set but we still stretch it after to spice it.
the pole out system is under huge load. We put a constrictor clutch on the ceiling of the cabin top. The cam cleat is good around the cans. But it’s not up to the job on long legs.
last Transpac we broke the dog bone on the bob stay. The water box held so we lowered a guy over the side and filled the whole with wet setting epoxy.
the pole out system is under huge load. We put a constrictor clutch on the ceiling of the cabin top. The cam cleat is good around the cans. But it’s not up to the job on long legs.
last Transpac we broke the dog bone on the bob stay. The water box held so we lowered a guy over the side and filled the whole with wet setting epoxy.
On one of our boats we used 12mm SK99 for the bobstay on a short fixed bowsprit, overkill but the factory bowsprit (this is a sf3600) kept cracking under too much flex so we went for the zero give option. Also when you test using the tack line I guess you are attaching it aft and then winching it? If so you’re giving it a lot of aft loading rather than the vertical loading you’ll see from a sail and essentially creating a 2:1 purchase on what you winch
Gracious
Member
Hows it going? Did you figure it out ?do you like the boat? Im very interested in how this boat does in PHRF
silversailor
Member
- 274
- 13
Actively looking for a J97e.
silversailor
Member
- 274
- 13
jerseyguy
Super Anarchist
Only J/97 for sale that I know of is in France and it’s not an “e.”
There was one up for sale recently somewhere on the south coast UK. Lovely looking boat, but a bit out of my price range.
Plus I've heard they struggle to sale to their rating on IRC, but that could just be hearsay as we don't have any around here.
I also saw an advert for one boatshed Texas, but maybe it was an archived one from a few years ago. You didn't mention your location?
silversailor
Member
- 274
- 13
I bought my 2018 J97e out of Corpus Cristi TX last June. She's now in South Haven, MI where we race on Lake Michigan. Some questions:
1. Bowsprit length (can't seem to find it online)?
2. Tuning guide?
3. Pics/drawing of jib inhaulers?
4. Head plumbing diagram ?
5. Go fast advice?
Thanks.
1. Bowsprit length (can't seem to find it online)?
2. Tuning guide?
3. Pics/drawing of jib inhaulers?
4. Head plumbing diagram ?
5. Go fast advice?
Thanks.
