All very interesting information. And I think I follow both procedures. My real question is a little more mundane and perhaps a little novice. Is this at all necessary? At what point does this tuning truly need to be done? I think I get the idea that it will improve sail shape and mast rake, but is this just for the racing enthusiast who/wants needs to get a few more kts from his boat or is this a real problem for the average sailor? Or rather is this just a tuning up tip for those that have the time and inclination? I do see the point of all if you lose or brake a shroud and need to equalize the new and old.
Allan - your hitting on the dividing line between racers and cruisers. As a confirmed cruiser, I tighten the rigging to get the recommended mast rake, and no pumping of shrouds under sail, and dont touch them during a season, basically. Im tacking through 100 degrees with the genny - a jib would do a lot better.
Racers spend their time trying to eek out performance - but if you really want to push this up, first step would be upgrading sails like delevi
Thanks Cat I think I get the Picture. Just trying to learn a little here from people who have "been there, done that". So this is a concern only at the first set up in my case, as the boat will be in a marina and the mast will never come down unless I decide to trailer her somewhere.
At what point does this tuning truly need to be done?
In my mind it needs to be done only once. "If you hit the sweet spot on your first try" It took me 3 seasons of tinkering 2 or 3x a season to get it right. Now I just run with the setup I like.
I would give everything a cursory going over at the start of every season to make sure your rig is tight and right but other than that once you find your optimum set up no need to make adjustments.
On edit. Some adjustments you wont even be able to feel a difference. Some (small tunings ) will make a huge difference.
On editing the edit: Make sure you know what your boat is doing that you don't like ie: rounding up, weather or lee helm, spilling your beer etc. and review the web sites with rig tune info to assure yourself that the adjustments you make will in fact impact the issue.
Very first result when googling "Fractionall rig tuning"
At what point does this tuning truly need to be done?
I'm still tinkering. I'm finding that a short forestay works well for the but causes the mast to point forward a bit... not sure if this is really a bad thing. To compensate, I will be using about 470-500 lbs tension on the upper shrouds and just enough on the lowers to keep them snug... probably around 120 lbs. I'm hoping this will create enough mast bend so that the forward (negative) rake is all due to bend whilst the top of the mast is about vertical to the mast step. I'm currently at 420# on the uppers and 200# on the lowers. This produces a very small amount of bend... still too much tension on the lowers... and the top of the mast still points forward slightly. It is a delicate balance. Too much upper shroud tension can make the mast difficult to rotate. Also, it shouldn't exceed 15% breaking strength, which is approx 490#. I read, however, that on fractional rigs with swept-back spreaders, you can go up to 20% but the 660# on upper shrouds will really make mast rotation a challange. At this point, I'm unwilling to lengthen the forestay just yet.
guys this has been a great post but ill go with the simpletons aproach,uppers 300lbs,lowers 270
Thats a good start for rig tension, doesn't address the angle of your mast. Is it perpendicular?? This may sound like a silly question but when I bought my boat (many years ago) I wondered why it sailed just a fraction better on one tack. The stay and shroud adjusters were in the same hole on opposing sides. Turns out that the mast was leaning to one side.
When I got new shrouds, they had exactly the same issue. One slightly longer than the other.
It also wont help with rake. When I bought my boat we just pinned it together at our home lake. Turns out it was set by the previous owners with something like 8 deg of rake.
wheni stand looking at my boat,the mast had quite a lot or rake in it,ive tightened up the furler,im still waiting on my loos guage arriving so ive set the uppers and lowers by feel,prieviously they felt slack,i added turnbuckles in place of the macgregor plates,my back stay does not feel too tight but ill leave it as that.My Mast was rattling around in the wind before i changed to turnbuckles.
ill have a good look at the mast to check for it being perpendicular
i was hoping to rig the boom and pull up the mainsail today but its touching 30-40 mph winds,i wanted to start on my reefing mods
my plan was to put her in the river this weekend and sail her out to sea but,we have winds with snow and sleet and a forecasted strenght of between 6 and 9
What goes 'round, comes 'round. Curiously, Scott has linked to a rig-tuning article by Bruce Whitmore. But Bruce's first sailboat was a Mac 26X, and his first rig-tuning article was published right here, by Heath. Fact is, you'll see that Bruce based his notes on his copy of Brion Toss' Rig-tuning video.
but causes the mast to point forward a bit... not sure if this is really a bad thing. To compensate, I will be using about 470-500 lbs tension on the upper shrouds and just enough on the lowers to keep them snug... probably around 120 lbs. I'm hoping this will create enough mast bend so that the forward (negative) rake is all due to bend whilst the top of the mast is about vertical to the mast step. I'm currently at 420# on the uppers and 200# on the lowers. This produces a very small amount of bend... still too much tension on the lowers... and the top of the mast still points forward slightly. It is a delicate balance. Too much upper shroud tension can make the mast difficult to rotate. Also, it shouldn't exceed 15% breaking strength, which is approx 490#. I read, however, that on fractional rigs with swept-back spreaders, you can go up to 20% but the 660# on upper shrouds will really make mast rotation a challange. At this point, I'm unwilling to lengthen the forestay just yet.