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J/24 Masthead Kite


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#1 noblemetric

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Posted 20 May 2013 - 09:00 AM

Im hoping to race a J/24 under IRC and want to put a Masthead Kite on it. (No One Design Class near me).

 

Does anyone have suggestions as to how that could be rigged without taking the mast out of OD rules? I want to race OD in the future. 

 

How would I attach a temporary sheave or block on the top of the mast?

 

Does anyone have a pic of the J/24 masthead? I havn't seen the rig yet.

 

 

 

 



#2 clamslapper

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Posted 20 May 2013 - 12:39 PM

I have heard of J24 guys messing around with a masthead kite in light breeze.  You can just tie a line through the mainsail halyard eye, and put a small block onto it with a halyard.  Unless you're dead downwind, i.e. with the backstay taking just about all of the load, or in an extremely light breeze, you would need to figure out some way to attach shrouds of some sort to the masthead or the top of the mast will surely break.

 

Out of curiosity, if you've figured it out: what kite were you proposing to use? 



#3 noblemetric

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Posted 20 May 2013 - 12:56 PM

Thanks ClamSlapper. 

 

As I have said, I have not seen the rig yet. When you say "mainsail halyard eye", are you suggesting that I tie a line through the eye in the mainsail headboard? Where the main halyard clips onto the sail? Obviously this would have to be done while the main is up and taken off before the main comes down?

 

Haven't figured out what kite to use just yet. But am very keen to try this out. 



#4 BalticBandit

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Posted 20 May 2013 - 12:58 PM

I've got photos of my masthead crane somewhere, but the simplest way would probably be to replace the masthead plate (the bit covering the open end of the extrusion) with a bigger bit of AL.  one that overhangs the front of the mast with enough material to drill a hole for a swivel in it.  Keep the old top-plate to put back.  You will also want to probably up the size of the screws holding the plate in place to accomodate the sheer -but none of that should take you out of compliance.

 

That said, I agree that you might want to make the plate "oversize" on the sides as well and rig up some spectra removable runners to take the lateral loads on the mast..  I'd attach them by quick release  shackle to the stanchion plates and only have them on when you raise the kite. 

 

Something like turn down deep, set kite,  connect runners, cinch up windward runner (4:1 should be fine) ease the backstay and then heat up.

 

for the gybe, back stay on, turn down blow windward runner, gybe, cinch up weather runner, backstay off.

 

But I'm not convinced the area you get will make up for the ratings hit



#5 noblemetric

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Posted 20 May 2013 - 01:21 PM

Thanks Bandit. 

 

Interesting, using a modified mast plate sounds like a slick way to do it. I will try to find pics as to what these look like. 



#6 Bump-n-Grind

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Posted 20 May 2013 - 01:39 PM

How much would it cost to just buy another mast for the boat and rig it up to be your "turbo" stick?

Add some upper shrouds, Halyard exit block and bob's yer uncle. it's not all that hard to pop a mast in and out of those things.

 

Just a thought. but that's how I'd do it .. not that I would...



#7 BalticBandit

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Posted 20 May 2013 - 01:55 PM

Here's what the existing Mast Cap looks like

 

http://www.apsltd.co...tboomparts.aspx

 

2470.jpg

 

Basically make it thicker and a bit bigger.   but again, I don't think you will see a performance gain to offset the ratings hit.  When I first started racing J-24s i kinda felt the same way about sailing against masthead kites going DDW.   until I learned how to sail the J-24 almost by the lee with the kite massively over rotated to weather with the pole about 5 deg too far back and 6" of tip too far down.  I was then able to keep pace with a 30'er DDW and eat them alive upwind because we just sailed flatter



#8 noblemetric

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Posted 20 May 2013 - 03:34 PM

Great - thanks all for the advice. Ill take a look at the mast cap idea and see if it works out. I also pay close attention to the rating hit before I try anything !



#9 BalticBandit

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Posted 20 May 2013 - 03:54 PM

The thing to realize is that the "stock" J-24 rating is pretty aggressive, and that means that anything you do to make it faster will really be a pretty steep hit and take you outside of the "well known zone" so suddenly all the things you have been reading about J-24s off the wind may no longer apply.  



#10 some dude

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Posted 20 May 2013 - 09:31 PM

2 masts. There was one in So Cal that had a masthead rig for MORC back in the day-masthead kites and genoas.  Connected to existing chainplates etc so you just swap between MORC and OD configurations.



#11 kmcfast

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Posted 20 May 2013 - 10:17 PM

http://forums.sailin...howtopic=141686

#12 Ned

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Posted 21 May 2013 - 03:27 AM

Here's what the existing Mast Cap looks like

 

http://www.apsltd.co...tboomparts.aspx

 

2470.jpg

 

Basically make it thicker and a bit bigger.   but again, I don't think you will see a performance gain to offset the ratings hit.  When I first started racing J-24s i kinda felt the same way about sailing against masthead kites going DDW.   until I learned how to sail the J-24 almost by the lee with the kite massively over rotated to weather with the pole about 5 deg too far back and 6" of tip too far down.  I was then able to keep pace with a 30'er DDW and eat them alive upwind because we just sailed flatter

And ease halyard out a bit, heel to weather a bit, constantly soak to leeward on every little wave.  Keep one eye on the spinny luff and one on the mainsail leech.  Practice practice practice.  

 

To use a bigger kite you need a much longer pole.  That is where they'll kill you on rating.  Listen to BB and try the finesse game first. 



#13 BalticBandit

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Posted 21 May 2013 - 05:42 AM

Oh and downwind, you need a "middle" crew that steers with body weight as you call it.   At a nationals, the boat I was on was not slow downwind, but the winner went by us gaining about 4 BL on the run simply because his middle was doing the steering and the skipper was comfy with the boat heeled slightly to weather  (mine was not). 

Remmember that heeling to weather generates lee helm, which downwind means your rudder/keel combo are "lifting you" downwind.



#14 Speng

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Posted 21 May 2013 - 05:18 PM

The thing to realize is that the "stock" J-24 rating is pretty aggressive, and that means that anything you do to make it faster will really be a pretty steep hit and take you outside of the "well known zone" so suddenly all the things you have been reading about J-24s off the wind may no longer apply.  

He's talking IRC. If you just go m/h with no change in the kite shape there's no rating hit under IRC AFAIK. If you were going to trick out the boat IRC-wise you might try optmising your upwind sail plan first/as well. There was another thread here where they talked about the IC24 sail plan which is a jib slightly bigger than the OD blade and a roachier main which would probably rate better under IRC and be more suited to (presumably) Bristish conditions



#15 BalticBandit

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Posted 21 May 2013 - 09:19 PM

Hmm  I was assuming he was going for a taller kite.  If not - why bother?



#16 ~HHN92~

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Posted 22 May 2013 - 01:19 AM

A friend of mine used a Morgan 24 kite with the stock pole. He tied a block to the top of the mast and left the halyard external, as this was a temp MORC Nationals thing one year. Another 24 tried a frac wider kite with a cheater pole but was not as fast.

 

Stick ddw in light stuff and you're OK, anything other, watch out.



#17 firesail36

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Posted 22 May 2013 - 12:52 PM

Just finished placing a mast head kite on my J-24. I had a custom built .5 oz spinnaker matching the stock pole. For PHRF for Northern California I received a six second penalty. The rating changed from 168 to 162. I use the mast head kite on long distance races and then sail our 168 class buoy races with one design set up. I matched the sheave in front of the mast head (opposite off main sheave) and stay internal. Not J-24 class legal but very functional. Boat won't be leaving the lake for district or national events.

I race on a Northern California lake called Clearlake. Average wind is 9 knots. We have long distance races of 26 and 17 miles each year plus Friday night races that I use the mast head kite. A big power difference and breaking even on rating change with a very completive 168 fleet- J-24, Capri 25 and Merit 25's.

#18 OBW

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Posted 25 May 2013 - 01:14 PM

As said above easy to add a sheave to front of mast and run halyard internal. Have a boat here that does the J24 masthead and what a difference in anything under 15. No jumpers added need to carry some backstay on when breeze is up around 15knots. The J24 mast section is pretty stiff and handles the larger sail just fine dead down or reaching. Has no trouble sailing to the rating hit 

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#19 Gouvernail

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Posted 26 May 2013 - 05:49 AM

Were I to try speeding up a J-24 for PHRF I would add a torpedo to the keel bottom. 

 

Redesign the lifelines so they attach outside the hull side to help hiking.

 

Put a big roach on the mainsail. and add a longer boom

 

 

strip EVERYTHING out of the inside.






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