does the clew outhaul on the main, do the same job as the vang adjustment?
if so, is a vang needed?
Is your question regarding a conventional, a swing or a McCormack rig.
Once we know this, help will follow.
Hi Ian
Haven’t heard about that one before (smile). Where can I find out about a McCormack rig?
regular marconi (macaroni) style, with the boom pivoting on the mast.
Hi Nigel …
The outhaul helps determine sail shape … the tighter you pull it the flatter the sail and the better suited it is for stronger breezes and vice-versa
The vang keeps the boom from riding up when sheeted out thus allowing control of sail shape on a run …
On a typical rig with a pivoting boom you need both … with a fixed boom all you need is the outhaul.
T
that’s the answer i was looking for.
i plan on concockting a single-plane pivot for the boom, so it can only move side to side. thus eliminating the vang, and using the outhaul for the shapes.
any progress with yre bluesky? i have some new parts that i’m gonna send ya to try out. just gotta make them, and i’ll stick’em in with yer other stuff.
glad to help … as for bluesky when the bulbs arrive I can sort out weight distribution and position of keel trunk which in turn leads to postition of mast and from that sail plan follows … servos will determine rudder config and mech … T
Nigel, the purpose of the boom vang is to control the amount of twist in the leech of the mainsail.
The amount of twist is one of the most important aspects in the tuning of the boat for best performance and should not be underestimated in its value.
TWIST… can adjust… the amount of weather helm, the acceleration out of tacks, the amount of grip of the breeze, power of the main and relative drive with that main verses healing force for the ballast ratio of your paticular craft, rig balance upwind and down, twist can be automatically changed from hard in to full out of the boom position by clever but simple engineering and should be altered with the wind speed.
So you can see that your decision to do away with a vang may need some further thought. :lol:
The outhaul is for the control of the draft of the sail as stated by tmark and is important as well.
Everything is important in a craft so small and we are working in tiny increments for vast differences…:devil3:
It is not a case of “GET IT RIGHT AND HAVE IT WELDED” :graduate:
http://www.rcsailing.net/forum1/showthread.php?t=3898
Lester you will need to start here and plod your way through the posts where you will find “everything you need to know but were afraid to ask.” 
Hi Ian
OK, got it, McCormack rig = swinging una rig…! Nice.
thanks ian. i didn’t know that each (vang & outhaul) had seperate jobs.
to my untrained eye, it looked as if they (vang & outhaul) were doing the same thing.
one for twist adj, one for draft…got it.
thanx again all