Got a 2008 Nacra 20, with E/P Sails, and was wondering where everybody is finding the sweet spot. Raked the mast back significantly last weekend and it was a lot faster in heavy air. Saw the Narca 20 trim sheet on Nacra Euro site, but I believe that is for the Performance Sails.
Here's what I've got -
Mast Rake - Measurement from forestay comes back to top of lower rudder spindle on the transom
Spreader Rake - 1-7/8"
Diamond Tension - #600
Anybody trying anything else that's on fire?!
I'm measuring mast rake back on the extended rudder - about 1/2 way down the rudder blade is as far as I go. Spreader rake sounds about the same as mine but I'll run 800 lbs on the diamonds when it's cranking.
We are just starting to learn to sail this boat, so for what it is worth:
We have (2008 model) 'general setup' by the dealer (Nacra Euro) with perf sails:
>>Mast Rake - Measurement from forestay comes back to top of lower rudder spindle on the transom
Our Mast Rake - Measurement from forestay comes back to half way between round inspection hatch and transom.
Martijn
We have (2008 model) 'general setup' by the dealer (Nacra Euro) with perf sails:
>>Mast Rake - Measurement from forestay comes back to top of lower rudder spindle on the transom
Our Mast Rake - Measurement from forestay comes back to half way between round inspection hatch and transom.
Martijn
That me be OK for very light winds - but my experience has been to rake back a lot more than that.
He might be taking his measurement from the forestay/bridle connection... I guess...
That does sound quite a bit forward.
On a side note, I'm glad that some of this is being discussed because I've been trying to get some finite rig settings discussed for the boat for a while. Everyone I talk to seems to have different thoughts on the matter, and nothing is ever
concrete
and its more of a
move it around until you like it
type of thing... which for someone who doesn't know what he likes, makes it quite difficult <img src=
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Do not make comparisons against the EU Nacra 20's. Their sails are quite different and thus the tuning is quite different. Yes, I speak from experience. No, you can't touch this.
Halfway down the transom is the way to go with E/P sails, unless it's a complete drifter. Bring it forward a pin or so then. Spreader rake, well, 1.75 inches sounds good to me. 600 diamond tension is pretty frickin' low. I'd stay in the 675-800 ranges, always.
PS: Tad's spinnaker looks like Ronald McDonald's underpants.
Good to have you back. (in an attempt to get this moved to the squirrel thread <img src=
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I hadn't thought much about Gertie's Mast tuning until I replaced the diamond wires and had a couple of discussions with my favorite sail maker. My understanding is that the mast should be as straight as possible and have enough diamond wire tension to prevent the mast from inverting under the load of the spin. I don't recall him suggesting that the mast should have the same prebend as the mains luff.
Gertie's mast WAS set up with the following:
Spreader Rake: 1.75
Wire Tension: #38 or #39 (Loos Pro gauge) = 700#s - 800#s
Mast Prebend: 1.5
Sail draft: not so much
Mast Rake: ?
Rig Tension: Good for last Sunday, too tight for this past Tuesday night.
I have now backed off the tension to about #36 = 500# range. (Tension drops off fast).
Mast Prebend: I'll measure tomorrow
Sail draft: Hopefully more than before
Mast Rake: I'll measure tomorrow
Me favorite sail maker also suggested that I do a sail maker bolt rope adjustment. Apparently, the type of ropes that are used as bolt ropes are highly subject to shrinkage. This shrinkage cause wrinkles that the sailor then applies downhaul to remove, often more than is necessary resulting in a flatter sail than desired. He also said that it was very easy and that I could do it myself.
Sorry it took so long to get to this,
More info on the bolt rope replacement when you have it please.
I wasn't doing a bolt rope replacement. I was going to allow the bolt rope to shrink up inside the bolt rope cover per my sailmakers recommendation. To do this the sail maker said to check how the bolt rope was secured to the bolt rope cover. If it is stitched along the entire luff then all that stitching would need to come out. Since mine was only stitched for four or so inches near the bottom it didn't take very long to remove the stitching. After stitching is removed the bolt rope will move up what it needs to or try milking it. Mine didn't move at all so I relocked stitched it place. Had it moved up, the sailmaker said I would have needed to add a piece of line in the place of where the old rope was to provide support to the luff; keep it from tearing.
I might consider getting a second opinion about that before you start removing stitching 😛
Mine is the second opinion. <img src=
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Remove the lock stitching that goes thru the bolt rope cover and the bolt rope. Do not remove the stitching that holds the bolt rope cover to the sail material. Go look at your mains bolt rope. No magic necessary.