Will it make righting any easier once it is wet and has absorbed water?
a moving rigg isn't bad. Actually it has improved aerodynamics. In many dinghi classes
pumping
(e.g. periodical change of the sail inflow conditions or sail angle) if limited or forbidden, because people feel that their seems to be an advantage by doing so.
Hovever if the motion causes excessive hull drag due to splash or nose diving, it can't be good. There are many possibilities to do cure the problem: Hull shape, T-foil rudders and reducing inertia.
Reducing inertia is always good, but unfortunately the standing rigging is only small part of the mast-sail system and this is only a part of the whole boat inertia. Hence the gain by playing with lighter standing rigging is small.
Hull shape has significantly improved in the last years. For example my Javelin sails far smoother in waves than the 4 ft longer Tornado. I would expect similar or even better wave-going behaviour for the F16, becase of the lower mast and lower inertia.
The most efficient way would be a T-foil(ed) rudder. It will not only damp the pitching motion, but transfering the energy from pitching in thrust (negative drag). However in calm water you would have drag penalty.
The advantage of essier rigging is on F16 size boat fairly low. I didn't feel any difference.
The jib makes a difference: From your comment I see that we agree that a sagging jib is not good (especially upwind). If you don't have a too flexible mast the main sheet will keep the forestay tight. But when you react to a puff by opening the main your jib would start to sagg in exactly that situation where you want a flat jib.
Every rope from organic (e.g. plastic, anorganic = metal) suffers from UV and water. The question is how fast.
BTW I know of carbon fiber only used with resin, hence a rod and not a rope. So the UV and water resistance of the resin would be important. It should have some addtitional protection (e.g. PU or wax).
I guess some googleing would reveal you, that
Dyneema is good againbst UV and water (I replace the unbraided dyneema ropes on my boat only once a year), Vectran is used for tugging dipping sonars and on space-exploring vehicles, hence I would think of good resistance as well. Aramid and PBO are on the low end of the table.
I can tell you that Aramid (Kevlar) has so poor water resitance that we don't use it in our business (even not with epoxy resin and PU coating), but an aircraft has a different utilisation of course.
Regarding the drag increase due to diameter, I think I made some calculations already on this forum.
Btw is 5mm a bit much for a single hander?
Cheers,
Klaus
Moving rig due to elasticity in the stays is for sure slow. No other way to look at it, just plain slow.
The best way to reduce pitching from weight aloft is to reduce the weight <img src="<>/smile.gif" alt="smile" title="smile" height="15" width="15" /> The hard part is to achieve that without the drawbacks of some of the cheaper solutions.
On the topic of Vectran and UV..... its a shocker! its been a while since i used the stuff but I recall it was suffering 50% los in strength within weeks of being exposed. Its up there with PBO in that regard.
The thing to remember is that there are some really nice solutions to these problems, like easy rigging who have a nice way to seal the fibres in a watertight and UV proof cover, so the PBO from them lasts a very long time (we use X40 stays like this for more than 5 years)
Also the Maffiloi ultrawire is a good mid range solution too.
Hi Rolf,
I have been using 3mm SK-90 Dyneema for about 14 months with out any issues.
What I did learn was that you need to put in your first thimble them stretch the line before measuring and putting on the thimble at the other end.
My biggest complaint is that I can't find SK-90 in 2 or 2.5 mm!
I sorry I have not been keeping up, did you get your boats in the water?
Les
it looks like synthetic rigging is becoming more and more common in the yachting world. Have the time now arrived for beachcats also to go synthetic?
For our boat I am serious about using synthetic for all stays but keep the diamonds in SS wire.
Earlier it was suggested to keep some SS wire for the sections wrapped around the mast when rotating the mast. Still valid?
I have seen Colligo Marine referenced and SK78Max as one line option. Others?
Anybody with experience or opinions?
Thanks for the input Les!
Could you write a small summary of the pros/cons of synthetic rigging as you see it. A load of pictures and some tips on how to rig would also be most welcome <img src="<>/smile.gif" alt="smile" title="smile" height="15" width="15" />
No boat in the water yet. Tonight I waterproofed the nuts for the beambolts. Will continue with the rear beam nuts tomorrow night. Then the main and rear deck goes on and we are full on with the accessories like rudder system, sails, dolphin striker etc.
I also worked on the Y axis of my CNC mill conversion so I do some other stuff in addition to the boat build. Every workshop of course needs a small CNC mill..
Rolf, I'll see what I can do.
RE. the CNC let's see some shots.
Les
Here is a shot of the mill itself with the completed X axis drive fitted.
![[Linked Image]](http://www.catsailor.com/forums/ubbthreads.php?ubb=download&Number=12574&filename=IMG_0213_small.JPG)
Other shot is from the lathe where the base for the Y axis thrust bearings is machined. Please note the homemade boring bar which I am fairly proud over having built <img src="<>/smile.gif" alt="smile" title="smile" height="15" width="15" />
![[Linked Image]](http://www.catsailor.com/forums/ubbthreads.php?ubb=download&Number=12575&filename=IMG_0214_small.JPG)
Still a fair bit of work to do, but it is a lot of fun!
OK Rolf here goes.
At the mast end I use a T-Ball bail Terminal with two sailmaker thimbles. The thimbles are cut and put on the T-Ball Bail and the weld closed then sand and polish to remove any burrs. Say your T-Ball mounts on the mast at 7 meters, you would mark 16 meter of your shroud material at the half way point and then using a brummel ( http://www.animatedknots.com/brumme...
![[Linked Image]](http://2.bp.blogspot.com/-kfDBJLxTNmg/UGzsxJmXBAI/AAAAAAAABM4/84A6ReKAHcI/s1600/2012-10-01_07-39-52_v1.jpg)
After you stretch you line, measure and put the thimbles on the ends of the shrouds, remember to orient the lines as one will want to come off the bail facing back (main shroud ) and the other facing forward (Fore stays). I also attach the trap lines to the thimbles.
![[Linked Image]](http://2.bp.blogspot.com/-zqrWK1n3NlQ/UGzsxYL8KkI/AAAAAAAABNA/tOYvUZK6GkU/s1600/2012-10-01_07-41-50_v1.jpg)
I hope this helps someone.
Les
It just came to me that you F-16 guys use a single fore stay.
So you would need three thimbles. But this would make the termination a much simpler job.
Les
Thanks Les!
Nice and easy! Only complication for a home-shop would be the welding. This could be overcome by using a largish shackle to collect the stays with thimbles and mount them to the mast fitting. My mast does not have the slots for T bail terminals.
Looks very doable!
Rolf,
Do check that the cable thimble and the shackle are compatiable, the bolt eye of the larger shackle needed for 3 stays ( 4 in the case of an A Class rig )will be a tight fit through the 3mm thimble as I discovered.
The other thing I found using SK75 was that under load the Brummel knot locked it off beautifully but under very light loads with slight
jarring
effects, the knot would gradually slip through ( the rope is quite slippery and naturally oily to touch ) and eventually release ( as I also discovered ), I found that simply sewing a couple of loops through the tail section stopped this.
Do check the breaking strain as SK90 is about 1.5 times stronger than wire and you can afford to go down in diameter, I found the larger 4mm seemed to stretch /creep more than the 3mm and sort of reasoned that on first use, the smaller diameter
tightened
the weave of the new rope whereas the 4mm never seemed to really fully close the weave.
Guys,
You will 100% be slower if you make your stays and forestay with normal SK75/78/90 rope. The loss of power with the ropes is going to make a difference that you will notice.
If you dont believe me, go and try it with some straight line testing against a std boat.
Hi Macca,
what is the issue with normal SK90 rope ? The braiding?
pretty much correct. The braiding essentially puts the fibres off the direct line of load and as such they are never able to be properly aligned with the load, this also has a further effect due to the bundling of the fibres into 12 strands. there is always some space for these bundles to flex and compress which makes it more elastic.
Unidirectional fibre stays are the only way to go.
This subject has come up at Sailing Anarchy, with some of the same folks and some new thoughts on the subject.
http:/
Just read through it. Seems like the consencus is that fibre rigging will be the future. Just need some development, but no prob. to go bleeding edge on a hobby basis if we want to.
I liked the carbon stays! But how would they react to being bent around the mast when the mast rotates <img src="<>/smile.gif" alt="smile" title="smile" height="15" width="15" /> (I assume other fibers being used there). With carbon tow it should be possible to DIY carbon stays but the handling would indeed be a challenge.
Thanks for the link.