indoorff

My Feedback: (2)

Hey Everyone,

I have seen some pictures of a particular type of boom setup (see the attached photos), but I have not been able to find any information on setting this kind of system up (or even a name for that matter). As close as I can tell, both the main sail and the gib will pivot on the same boom, around bearing on the mast. I am in the process of designing a boat and just going through some options. The pictures I have seen are all multihulls, is there any reason this would not work on a monohull?

Thanks for any information,

Chris

Islander51

Swing rigs work just fine on Marbleheads, most of the top racers use them. [>:]

indoorff

My Feedback: (2)

Ah ha, it's called a Swing rig is it. Anybody have any more information on these? Googling doesnt seem to turn up a lot, there is one link on modelyacht.com for swing rigs that seems to be broken.

Chris

Islander51

Look here for a few pics,

http://www.mya-uk.org.uk/reports/doc..._Nats_2009.pdf

and here for the bits:

http://ww.pjsails.co.uk/w

mfr02

A conventional (note that things become conventional because they work) rig has the nice feature that when running downwind, the jib tries to lift the bow. With a swing rig, the entire rig tries to bury the bow. A hull that works well with a conventional rig might not be as good downwind with a swing rig. Of course, if it was designed with a swing rig in the first place, thats another story.
Arranging controls with a swing rig can be easier, and, since the forces each side of the mast tend to partially cancel, a smaller control device can handle the same sail in stronger winds.

indoorff

My Feedback: (2)

Thanks for the links. Arranging the controls is what I am interested in and have not been able to find out much info. Even though the jib is attached to the boom that pivots with the main sail, it does still appear to have its own independent control, am I right? If somebody had a diagram, that would really help clear thing up.

Cheers,
Chris

mfr02

It only needs an independent control if you really want one. There will be an adjustment to set the size of the slot between the leech of the jib and the mast, but this really doesn't need adjusting once the boat is sailing. A properly set up yacht will always go fastest when the driver stops slowing it down. The more things that can be adjusted by remote control, the better the chance of a bigger, better muck-up.

ianinshanghai

Once you have the mechanics of the swing rig constructed, it is a very simple rig to use. No need to independently adjust the jib once you have set up the slot between the jib leech and the mast.

This link is useful:
http://www.ivorbittle.co.uk/Books/My...20using%20.htm

and here
http://www.rcgroups.com/forums/showthread.php?t=547980

Some of the rigs have a "floppy" fporward section ("stick") that means the jib tack "flops" to leeward slightly to rest on the centrelinbe of the boat when th emainsail is not quite on the centreline

indoorff

My Feedback: (2)

Thanks, those looks like some really helpful links, I will have to read it and see if I can absorb the information.
So the jib boom is simply there so the jib can be free to move a small amount, and is not controlled in any way from the radio then?

Cheers,
Chris

mfr02

Yes, but if you want to, you can have control there. Its up to you. You could also have it loose-footed (no boom). A Marblehead champion back in the early '90's used all 7 channels to control his rudder and 2 sails. The next year's winner used 2 channels. Yer takes yer pick :-)