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H18 Mast Rotator Rule and Jib block Twisting
http://www.hobie.com/au/en/forums/viewtopic.php?f=13&t=7175		 Page 1 of 1
Author:  Jcraig [ Tue Jul 03, 2007 6:41 am ]
Post subject:  H18 Mast Rotator Rule and Jib block Twisting
Matt or anyone else,

I know there is a rule on what you can do for a mast rotator for racing but i can't seem to find the thread or rule. Also, i cant find the thread on the mod to keep the Jib blocks from twisting around (Matt, is this a class legal mod), as i remember the original thread was a little confusing on line routing can anyone provide a better description and possibly pictures?

Thanks,

Jason
Author:  tjp [ Tue Jul 03, 2007 7:37 am ]
Post subject: 
As far as I can tell from the class rules, jib sheeting and mast rotation can be set up in any way as long as it doesn't weaken the boat.

Other boats with restrictions on mast rotation, like the 14, say so specifically ("no positive rotation devices"); the 17 rules state specifically that a rotation-keeper can be used, and the 18 rules don't say anything about it, so I would take that as "do whatever", though using some type of rotation-keeper would be tougher as there is a jib in the way.

The 18 rules say specifically that any jib sheeting method is allowed as long as it doesn't structurally weaken the boat. On my one experience as an 18 crew, the placement of the cleating for the jib drove me nuts - always in the wrong spot (behind the shroud while trapping, etc.) and difficult to lock/unlock. I don't know how well it would work, but I think you could put cleats on the front crossbar, a turning block, and then run the sheet back to the cars and around the ratchet blocks. I know the Tiger I have crewed on did a similar thing for the spinnaker sheets - and besides giving a more solid cleat location and getting the majority of sheet out of the middle of the tramp (always a pain as someone ends up sitting on it when tacking), it also gives more wrap around the ratchet block = more holding power when hand-sheeting the jib.

Just my interpretation of the rules and my opinion, I'm neither experienced nor an authority, so don't take my word as either :)
Author:  ncmbm [ Tue Jul 03, 2007 8:04 am ]
Post subject: 
Agreed, no specs on rotater. Do anything you think would help. I ran pigtails on my jib prior to converting to a selftacker that eliminated the twisting. There are some purchase limitations on jib sheeting if memory serves.
Author:  Jcraig [ Tue Jul 03, 2007 8:17 am ]
Post subject: 
Thanks for the info.

One more thing, what is the selftacker? any pictures.

Thanks,
Author:  tjp [ Tue Jul 03, 2007 8:34 am ]
Post subject: 
A self-tacking jib has no overlap with the mainsail. Instead of being sheeted to a block on each side of the boat, it is sheeted to a car that runs on a track on the front crossbar, in front of the mast. When you tack, the car slides across to the other side - you don't need to uncleat one sheet and pull the other in. I think the previous poster adapted his from the Hobie Tiger system; in any case, if you are worried about class-legal, it isn't. Hopefully someone can dig up a picture, my explaination isn't great.

If you don't have pigtails on your jib, make some. Instead of attaching the jib blocks directly to the clew of the jib, attach the blocks each to a line (about 1.5-2 feet, an 18 sailor could give you a more exact number) and attache the other end of the lines to the jib. Besides letting take out any twist in the sheet, it can also eliminate the need for quite a length of jib sheet which is nice to clean up the deck (the jib sheet is already quite longer than needed for actual sheeting to accomidate the roller-furling).

Some people shackle the pigtails to the sail; I think it would be simpler to use a single line for the pigtails with a block at each end, pass the center through the clew grommet, and then pass the blocks through the loop this creates and pull tight. Anyone with experience know if there's a problem with slipping doing it this way?

ncmbm wrote:
There are some purchase limitations on jib sheeting if memory serves.
Limited to 3:1, though why you'd want or need anything more than the stock 2:1 is beyond me. Then again, I'm not the expert...
Author:  Jcraig [ Tue Jul 03, 2007 9:04 am ]
Post subject: 
Tim,

Thanks for the Selftacking jib explanation. I do have pig tails installed with a shackel already (the shackel just makes it easier to dissasemble).

The problem i (or my crew) has is the jib block itsself twists around during a tack not just the sheet twisting (seems to happen during tacks in heavy wind). There is some way to route a bungee from one block through the back of the tramp (drain hole grommet?) to the other block. It just seems like it would get in the way and i was wondering if there is a way to do it that leaves the tramp clean of any extra lines.

Jason
Author:  tjp [ Tue Jul 03, 2007 9:29 am ]
Post subject: 
Maybe a stand-up spring? Don't know how you'd get it on there though since the block seem to be permamently attached to the car.

This is one of the reasons I was thinking about putting the cleat on the front crossbar so it can't get twisted.
Author:  Jcraig [ Tue Jul 03, 2007 10:31 am ]
Post subject: 
The only thing is with putting the cleat on the front crossbar is the mast would and boom would get in the way. I typicaly have the crew standing straddled on the front crossbar during a moderately windy day. Good idea though very similar to a 16 jib cleat.

Thanks,
Author:  John Lunn [ Tue Jul 03, 2007 12:35 pm ]
Post subject:  Untangle Jib blocks
eMail me off line at lunnjohn dot magma at ca for pictures.

Get some high quality 1/8" bungee cord, tie it to the (s/steel) loop under the port jib block, thread it through the grommet hole at the centre-rear of the port side tramp, under the tramp to the starb'd side grommet.

Up out of that grommet hole, and tie off to the loop under the starb'd block. Adjust as required. This keeps the blocks more upright, with less flopping around.

Get some high quality 1/4" bungee cord. Tie/secure one end to the end of the front cross bar, like at the end of the dolphin striker rod. Lead the free end diagonally upwards, (with the jib sheets ABOVE this bungee cord,) to the diamond wire on the same side that you are working on. Thread the bungee through the diamond wire, around the mast, through the other diamond wire, and across (going diagonally downward) to the other end of the front cross bar. I tie mine off to the wing bolts. This bungee cord helps keep the jib sheets from getting tangled underneath the mast, allows them to 'run free' and will help prevent the dreaded 'spagetti on the tramp' syndrome.

All these mods are class legal, as far as I know, as they do not affect anything other than a bit of bungee cord.

If I knew how to post pictures directly on the Forum, I would. Any H18 sailors out there who can post pix to show this stuff?

Good winds
Author:  Jcraig [ Tue Jul 03, 2007 1:44 pm ]
Post subject: 
John,

Thanks that jib block mod is the one i am looking for. Pictuers would be great but i cant seem to get your e-mail to work. Please send pictures to [email protected].

Thanks,
Author:  John Lunn [ Tue Jul 03, 2007 2:19 pm ]
Post subject:  H18 Jib lines
Ooops, typo, email should be lunnjohn at magma dot ca.
I have emailed you off line with some reasonable pictures.
If you can figure out how to post them on the Forum, go for it
Author:  Jcraig [ Tue Jul 03, 2007 2:32 pm ]
Post subject: 
John,

Thanks for the pictures I have all the other mods done. I have a new tramp i bought 2years ago. I dont think it has the grommets you describe. That may be the problem i am having with everyones discription.

I am also attempting to post your pics with the link below.

Thanks again,

Image
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