I'm a new Nacra 5.0 owner/sailor and need advice on tuning, especially on improving its pointing and tacking ability. The boat is a 1983 and has not been sailed in years but is in good condition. Any suggestions or resources I should check out?

I (and others) have posted multiple times in the past on 5.0 sailing/tunig/rigging tips- I suggest you try the search engine for the forums (especially the old "original" one) as a start-

If you can't find anything E-me personally or repost and I'll try to help you out. I owned #1030 for 17 years (and ordered the first set of "racing" sails for one) so know a little about them-



Kirt

HI,

I love my 5.0.

Mike Fragale's "Catamaran Tuning Guide" (edited by our hosts, and used to be around here, partly on-line... look on this site for a link. The dead-trees version is on sale on this site too, and it's short, useful and informative.)

and



'Catamaran Racing: For The Nineties" (White/Wells) also helped me enormously.



Keeping the bows down is even more important with this boat than many others - drive the bows down so that that leading edge is half-way in the drink. You'll point better. Too-tight battens will hurt pointing. Blown sails too. A hard jib halyard will help you point, but it cut the power of the jib when sailing slower (in a rough sea) or lower. Being boardless, it does point best a couple degrees lower than boarded cats.



Dunno if 83 masts had adjustable spreader rake - - I'm told if your sail's not cut for prebend you don't want to rake the spreaders too far aft. Tight diamond wires will negatively imact pointing slighlty, in that they interfere with your ability to flatten the sail. Badly tapered or untapered battens can suck. I bought my boat with the darn things in backwards, so the draft was 'hooking' in the leach. You probably allready know, you want the skinny end in the luff.



This "Roll Tack" is described in both books, and the first time I got all the pieces inplace, I tacked so snappy I was headed downwind on the new tack before I knew it. (Actually did a 180 in less time than I used to take to tack, as in "How the *H3LL did that lakeshore get out front of us?")



Entering a tack, sail high up, traveler in, hard main and jib, but don't pinch; go for boat speed. Call to crew "ready about" or somesuch. You and crew go aft. Stay on the old windward hull, far aft, keeping your bows up as you turn up. Crew hand-holds the jib sheet (uncleats), gathers up slack in the non-working one, too. Call "helm alee" and turn up decisively, cutting the rudders steadily over, without jerking, and not exceeding about 45% of their travel. Much more than that is just putting on the brakes. With those long keeled bows up in the air, a 5.0 snaps around sweetly with moderate helm input.



As the bows pass through "the eye" of the wind, crew eases the old working jib sheet, while tightening the new one - no backwinding! Skipper dumps a foot or so of main sheet - this is very important, it will help you bear off in a few moments, on the new tack.



As the bows come out of the eye, crew crosses the tramp, going forward to begin digging those bows in again. Skipper lingers old-windward-aft as long as safe, in light-moderate air this means 'till the end of the tack, in heavy air, as the jib fills on the new side. Keeping the rudders steady is a good way to avoid "detaching" the water flow over them, which minimizes drag and maximizes helm output.



Let the jib fill first!!! The main will just "weathervane" you back up to dead-in-irons if you harden it before you have moving water over the rudders. But the jib, if hardened early, will pull you onto your new heading even with little helm. When skipper crosses, he may move forward slightly to help dig in the bows, depending on trim.



As the cat accellerates on the new tack, don't aim too high, trim the main in slowly as boatspeed begins to call for flatness instead of driving power, and head up as the seat of your pants advises.



More Tuning:

Pay attention to Rick's remarks on Rake and real helm verses percieved helm - Take Rick's advice and rake your mast in such a way as to center your cross bar when going to windward, *then* if you're pulling hard, *then and only then* rake your rudders.



Get the boat square, measure bow-to-bow then measure right-edge-of-transom to right-edge-of transom. Then check your diagonals for symetry.



Get your rudders parallel. Measure rudder-to-rudder at goth the leading edge and trailing edges, with the rudders locked down - the trailer's good for this.



If you need any other advice, email me.



You have an awesome boat. No pitchpoling. Green water over the bow and hardly even decellerates. Chick magnet. Did I mention "No pitchpoling"?



I have an unused "Skip Elliot" dacron main, and 2 gently used ones. Randy Smyth's making me laminates for delivery in a few weeks. Email me if you're interested in an economical new 'motor' for your toy. I just now ordered a classified ad on this site :-)



BTW.: where do you sail?



Sail Fast!



Ed Norris

enorris@gcnews.com

Thanks for the response--couldn't find the tuning tips on the old open forum or general forum.

Eric

Eric-

Ed's response is right on- Especially about the bows DOWN part- I tended to try to go upwind w/ about 1-2" above the water! If you have a '83 you have the "straight through" diamonds- I upgraded and that helped my pointing ability- Also get a 5.2 jib (that was an upgrade in the later '80's and they are vertical cut and slightly bigger but much better shape!) and the new rudders are larger and "kick under" the hull- IF you can find some cheap that would probably be good- I never made that switch due to cost! I also upgraded my main by putting on a short traveler track (ala the 5.8 and 6.0) and get a positive mast rotator (for downwind). Very important upwind to keep the mainsheet tight and "play" the traveler (otherwise you lose your leech tension as soon as you sheet out)- I had to "slot" my rear beam slightly to allow the track (you should have the separate "I" beam track) to rotate slightly to align the track and mainsheet tension so the car will run freely- You can also upgrade to an "X" style car and track (Harken, Ronstan, etc.) but it's pricey-

You should also have the integral hull bolts w/ no straps- IMO this is probably the one "weak point" of the older boats- Check your nuts (not in public) and make sure they are tight but do NOT overtighten! Use plenty of anticorrosion grease on them. I found some short, SS lock nuts, ground down the semicircular "spacers" under the nuts and used the stock nuts, snugged down well w/ the lock nuts on top (I wanted to make full use of the threads) and my boat did fine. I often considered retrofitting to the straps and if I had had a problem w/ stripping I would have (still have the straps!). DEFINITELY upgrade the downhaul- to at least 8:1- very important to help depower and point-

I modified my trailer by using 2 x 6" wooden boards between the front and rear trailer crossbeams w/ 1 x 3" boards added to inside as a "lip" and carpet over whole thing, kept the rear roller (boards attached just in front of and slightly below)- The "keel" is so straight it works GREAT! Supports the boat along the whole keel and the rear roller lasts forever since it is only used to load the boat (Skeg ends in front of roller).



Kirt

Hi, Kirt,



Ya know, with all the stuff I've read, nobody's explained what to do with adjustable spreaders, if you're *not* sailing with prebend. How do they help you point better than the straight ones?



Thanks,



Ed

Ed,



I have a 5.2 with the straight spreaders. The deal is that you have to rotate the mast more than boats with raked spreaders to depower the main. This is because you can only get the mast to bend on the minor axis (thinest cross section) but with the raked spreaders, they can induce "pre-bend" on the major axis and need to rotate less.



On the straight spreader that you and I have, more diamond wire tension allows less bend in the mast and will power up the main (light air, choppy water). Looser diamonds will allow you to depower (less drag / more efficiency) the main by flattening it more.



On my 5.2, in moderate conditions I should be able to put both my hands 12" up from the bottom of the diamonds and press them in touching the mast. If it get's windier, I back them off a bit.

Ed-

With the straight spreaders when your mast gets "loaded" it bends only sideways and the spreaders simply limit the amount of this sideways bend (between where the diamonds attach). With a sloop as the mast bends sideways it bends into the "slot" betweent the main and jib "choking off" the wind that is able to go between them and you lose power (only comes from wind passing around the sails). With the raked spreaders, as the mast loads up NOW the spreaders not only limit the sideways bend, but because they are raked behind the middle of the mast, forming a "triangle" in essence, as the forces on the diamond wires increase they tend to try to force the spreader forward- forcing the mast to bend fore and aft- Downhaul also helps here since it helps to apply a force between the top and bottom of the mast which also tends to "bend" the mast in a fore and aft curve- So now, as the mast loads up, instead of bending into the "slot" it bends forward, keeping the "slot" open and allowing the wind to pass around the sails more effectively.

In a "prebend" condition the mast is not really allowed to bend sideways (very much anyway) at all so the slot is more constant (ie even in light air where there would be only sideways bend of a non-prebent mast the prebent one is not bent sideways). With the raked spreaders you will use less diamond "looseness" to keep the sail powered up and out of the slot in lighter air and then allow the diamonds to force the mast to bend fore and aft, along with downhaul, to keep the sail flattened as you need to depower. The other "advantage" of prebend is you can then utilize the top of the mast (usually in conjunction w/ a squaretop main) to "bend off" in gusts by keeping the mast relatively straight fore and aft and reducing the wall thickness/ "roundness" of the mast section (ala the wingmasts on the "A" cats, Taipans, F 18HT's, etc.)-



Kirt

Thank, Jake. FWIW, mine's a 1995 w/ rake-able spreaders, and my new rags'll be cut for pre-bent mast. I just didn't know what benefit they convey if one's sail isn't apropriate for true prebend aproach.

You're saying that if you use the "loose diamonds" aproach, but rake 'em aft, the axis of bend is shifted from directly across the minor axis to a line somehwhere between minor and major, so the mast presents a better airfoil to the wind?



Got it.

So, there's really a continuum, from strait, 'Loose diamonds' through 'raked spreaders' and on into 'true prebend' depending on sail and mast and slot considerations? Example, Mark Michaelson sez they tried to get the N5.5 SL to prebend and after much fiddling, settled on raked spreaders with almost enough diamond wire tension to induce a true prebend....



It's all coming clear to me.



Thanks!

Ed,



Exactly. A prebent mast also has the added benefit that the mast doesn't flex as much into the slot between the main and the jib.