Pointing ability

[Jimbo41]

Hi folks!
After having got kitted out with a new set of Alverbanks, We noticed in a handicap regatta meeting that we weren't able to point nearly as well as all the other boats - the jib was backing the mainsail and also killing far too soon. Someone from the race committee with no previous experience with 12s suggested that our jib was too "baggy". Since I haven't had the boat for that long and have not yet attempted to tune it,  I was wondering whether other factors might have come into play. The Mast's a proctor C, she's a Tigress 3130 and she's got a mast ram but no lowers. To be honest, I also have the feeling that the outhaul can't cope with the length of the mainsail foot  from clew to "thingy".  There's nothing more frustrating than going out with the intention to win and ending up 14th out of 16 boots, half of which are classes which you should be able to thrash were the boat correctly tuned  

Any help would be gratefully received. Good sailing to you all  

Jim N3130 (Nutty Shell)

[davidg (Guest)]

Hi Jimbo,

Probably worth talking to Kevan to check on optimum sheeting angle/jib track position.

One or two ideas;

In my view the two critical things for pointing are the jib "entry" angle (the leading edge) this can be fine tuned by adjusting the luff tension line, tighter is flatter and will open the leach which may stop the backwinding.

More mainsheet leach tension will also improve pointing, but may reduce speed if it is hooked, so maybe a bit more kicker is required.

More pre-bend, less ram maybe move the spreaders back, will flatten the front of the main, and maybe you shoould play around with jib sheeting angles and sheet tension (maybe a tell tale on the mainsail 2' back from the mast and on the leach of the jib) will stop you strangling the slot, which is slow.

Hope that this helps.

David G
N3461

[Jimbo41]

David! Thanks for your advice. I'll look into it as soon as I've solved a transient problem with a leaky transom!

Jim N3130

[angus]

Hi Jim Try sailing faster then you won't have to worry about your leaky transom

[Tim L (Guest)]

Hi Jim,

check your rig tension too - if your leeward shroud is going floppy upwind then you'll struggle to point - pull it on as you're sailing upwind until it's just tight.  Ceck your main halyard isn't slipping/stretching too!

T

[John Meadowcroft]

interesting point Tim

rig tension may depend on either how stiff your boat is and whether you have carbon or alloy mast.  15 years ago fast was with a floppy leeward shroud with metal masts and boats that were not as stiff as the latest ships.  with a modern lets say 34XX boat with a carbon rig i entirely agree with more rig tension, but I am not convinced otherwise.  Not sure if it is carbon rigs want more tension or if it is the modern hulls that can withstand it.  likely to be a bit of both i suppose.

the sails should be fine, spend a little time on the shore sails up, both old and new looking at how they interact with each other when you have them in the 'normal' position that you use.  It would be very unlikely that your new sails would want to set perfectly in the exact position that your old ones did.

finally - are the jib luff wires the same length?  ie do you have the same amount of rake to start with.

good luck
meds

[Tim L (Guest)]

Yes, I remember 3007 was a bit bendy when it was breezy - but in less breeze I still tried to keep the leeward one tight as sideways bend on the rig is never good for pointing.  I've got a head-on pic from the breezy day at Porthpean 2001 and the rig (proc C) is still straight sideways despite masses of fore-aft bend and a slack leeward shroud.

Jim - have you got any pics from the day that you could post in the gallery, that'll be the quickest way to sort it.  Though if your jib looked baggy and was backwinding the main then maybe move the jib leads further back to flatten it.  Kicker should be on enough to bring back 4in of the batten in line with the boom (sorry - sucking eggs stage...) as an optimum.

Anyway, better go - think we've just turned side on to the waves and the stationery is getting restless....

T

[Mikey C]

13 degrees off the centreline is a good place to start for most Alverbank jibs sheeting angle

[Jimbo41]

Thanks lads!

I think I've got more than enough to try out. I have the feeling I should try out the older jib and see if the luff length is the same. I'll also try tensioning the leeward shroud - she was more than a bit more than panting. As for fotos, I haven't any head on, but I do remember that there was considerable lateral windward mast bend, which retrospectively, would affect pointing ability.

And lastly, Angus, a leaky transom is always better than a leaky bladder. The former fills but empties slower and the latter always fills quickly and empties  a wee wee  bit ( ouch! ) sooner than is desirable.... Also you can epoxy a leaking transom....  

Jim N3130

[angus]

You can try the epoxie on the bladder as well I used to no a vet that suck fish back together with super glue (don't ask). But is the boat water logged from the transom or...........

[Mikey C]

one of superglues main uses after it was invented was to help seal wounds...

[Jimbo41]

Angus and Mikey C,

Surprisingly enough, my work has had me looking into such Big Issues. There is still quite a lot used in Iraq I'm told. However, I the only thing I did of that nature with superglue on myself was to accidentally stick my eyelid....

Angus, this vet of yours, he didn't have a leaky (ahem) transom did he? Did he recommend mixing the stuff with beer, 'cos that way, it's easier to apply?  

Anyway, got some "rocket stuff" that is permanent in 4 hours at room temp, starts to gel after 5 minutes and can be used to fill gaps. It's also clear setting, so there's no unsightliness with wood.

 

[janeysailor12]

[Jimbo41]

Janeysailor! I'll take you up on that just as soon as we get back on the water. The transom is leaking from the historical "rear rupture" and  needs repair. See "Ouch!, back-end trouble"

Very light wind training Yesterday and we were pointing pretty well after I got the rig tension about right. I also got the sheeting angle more-or-less correct, thanks to Kevan's ballpoint pen marks.

Retrosepctively, I think the guy with whom I was sailing last time and who insisted that he take the helm wasn't getting close enough up front when on a windward course, with the result that the pointing was more than naff. we made up for it in the conditions by our at the end of the race fairly proficient roll tacking. Yesterday, Higher Management and I were outpointing just about everyone in our mixed class group. In fact, I kept getting messages from the training boat such as, "your'e pointing too high to windward" and "the boat's points too high". I think they just don't know what even a moderately well-tuned 12 is capable of.... Whilst others were having to tack up to the windard mark, we managed to do it on a single stretch.

It's a shame that out here we've got no one in the N12 sand pit to play with. Maybe this can become the subject of an invitation to come over and test the water sometime. We've not only got beer and pretzels but also lots of water and sometimes even wind.

Jim N3130

[Dave Croft]

A common problem with modern jibs is the tension in the luf. If your jib luff is too tight then it will pull the flow too far forward and you won't point. Put up the jib under tesnion thenplay with the luff tension by adjusting the string that ties the tack of the jib to the luff wire. I have had to do this on most of my N12 jibs and also recently on my daughter's new Cadet jib. ALso chaeck the sheeting angle fore and aft, I like the top tell-tales to lift a fraction before the lower ones which means you have some twist in the sail and the slot is not choked. Good luck! Dave C