tensioning Jumper stays

[Fly4rfun]

My mast came with jumper stays on it, One of them was broke near the fork attachment. Rudy at DR made me a new one very reasonably( i sent the good one for a guide) these stays go from close to the top of the mast through a 8 in V shaped spreader and terminates just above the side stay spreaders to a tab on the mast. cable length was 13 ft 9 in.

the question is how do I tension this set up. I know i could leave it off, but its what the mast came with so want to use them. I have seen photos of other DS1's mast with this on

thanks.
G

[tomodda]

Get rid of them, you'll be much happier. They're called "jumper stays," do a bit of googling and you'll see what they're all about. Long story short, we don't have backstays, so no need for jumpers. Worse yet, by limiting the mast bend, you can't properly set or flatten the mainsail. Took me an entire season to figure out why my mainsail acted so funny, then I got rid of the jumpers and never looked back.

If you must keep them, you adjust them by changing the length of the jumper struts. Look at the ends of the struts, there's a screw that goes in and out, changing their length and therefore the jumper tension.

But believe me, you'll be happier without them at all!

Tom

[Fly4rfun]

Tom,

wasn't quite I had in mind for advice, but good advice i believe coming from you. I will remove them , and store them pass them along when i sell the boat.

did a little reading , including a older post (2006) and the going thought was that they made the boat less responsive and forgiving. thanks for the steerage.

[tomodda]

Sorry, didn't mean to rain on your parade here, at least not to be so negative. Happens when I'm writing late at night. Let's just say that jumperstays are an early George O'Day idea that didn't pan out, they were fashionable at the time. Later DS models don't have them, for good reason. No huge harm in keeping them (as in they won't kill you), but why bother tuning them now when it's just as easy to remove them. That being said, at least for me it was "all or nothing." There's a double-bent rod inside of the jumper struts, is what keeps them on the mast. I couldn't get the rod off the mast (it goes thru two drilled holes), so I had to cut it off with my grinder. No harm done to the mast itself, but if I ever want to reattach the jumpers, I'll have to get a stainless rod and bend it up properly. That juice is just not worth the squeeze, though. Better off without the jumpers, and if I ever sell the boat then I'll tell the buyer that I did them a favor!

[Fly4rfun]

Tom,

No rain here, glad to know that I'm better without them. I'll remove and keep them. i'm going to leave the little "tits" the spreaders fit on. as the protrude about a inch. just in case.

G

[tomodda]

Hahahha, yeah the "underspar" supports do look a little like Madonna Cone Bra circa 1990 You may want to cover them with some tape though. Not for mast modesty, just to avoid anything (halyards?) getting caught on the edges.

All kidding aside, once you rig a good vang (12-1 or higher), you'll really see the advantage of the "bendy" mast. While close hauled, you can pull the vang on hard, which causes the boom to press in on the mast and the entire mast to bow... like a bow and arrow. Which then flattens out your mainsail - depowering it if you want but also moving the chord (deepest point of the aerofoil) forward and back atwill. It's like a gearshift, do you want more power (deeper foil) or more pointing ability? Another way of looking at it, as you are a pilot, is that you now have a wing that you can reshape in the air. Not just move around your aerelons, actually change the geometry! The outhaul, main halyard, cunningham, topping lift, and traveller (or mainsheet/vang combo) all have their part to play too, it all works together to change your geometry. It's a wonderful toy for aerodynamics geeks Oh, and a good day's sailing!

Walk before you can run, don't worry about putting all those controls on your mast yet... but that's where you'll be going, so why hobble yourself with jumper stays? And as I wrote above, it took me a whole season to figure out that I should get rid of the things. I think what finally convinced me was the day that I had a friend at the helm and I sat myself by the mast and looked up. That thing was bending all over the place! A weird S-curve at one point, and visibly bending to windward (!) at another. I looked at all the horrible creases and backwinded bubbles on my mainsail and said, "Those jumpers gotta go."

And be advised that post-pandemic, I'm going to lure you down to the Chesapeake. DS1 to DS1 match racing on the Piankatank! One of my favorite places to sail.

[Fly4rfun]

Tom,

did you take off the tabs the forks attach to, or just leave them

[tomodda]

Off. Needed to do it with a grinder, but i left a clean mast (except for the holes).

[GreenLake]

Mine have come off as well, but I just taped up the pointy bits and didn't bother cutting. (Yet). Too busy sailing the last few years.

[Fly4rfun]

thanks for the input

G.

[Fly4rfun]

Well, the dastardly deed is done, jumper stays and hardware are gone. even the pointy things, did leave the band they were welded to on.

[tomodda]

You'll never look back! Here's hoping for a few more sailing sessions before winter sets in...

[Fly4rfun]

Tom its below freezing here right now, but going to get warmer on friday, It will warm up, then I'll take it out on a 2600 acre lake close by. let it spread its wings

[tomodda]

Expecting the same warm-up here. A warning, though, for this time of year. Water temperatures below 50F can kill you from hypothermia. That's my "end of season" cut-off. And it's not just that you feel cold, it's that below 50, you'll go into involuntary spasms and drown (you can still die above 50, but slower). Anyway, again not trying to be a killjoy, just saying be careful out there!

If you do get out, pay close attention to how the top 1/3 of your mainsail behaves without the jumpers. It's subtle, but makes a difference.

Tom

[GreenLake]

When conditions are like this, the wetsuit comes out.

Extra thick and a special top for cold conditions. For a transition, perhaps a standard weight one would suit.