Hey folks I’m working on a radial jib fitting… and I wanted to toss it out to the masses and see what you all think…
I’m not trying to one up manny’s but make it easier for those of us to build who dont’ have access to a metal shop…
the only problem I see is that it will need plenty of forestay tension to work… whereas manny’s did not rely on forstay tension…
for the “u” shape I am considering making one out of 1/4" aluminum for my ec12 I’m working on… and maybe one of Carbon for my vic…the spars and vangs will be regular vangs/vittings we already use…
Hi Marc
I’m thinking you will never get enough jibstay tension to control the twist.
If you could label the attachment points and such on your drawing I could explain my thinking.
Don
I’ll throw my thinking out there and see what you think…
Currently on RC boats you have the jib club attachment point about 1-2" aft of the leading edge of the sail. with your forestay and jib attached to the forward most point of the club. this offset attachment put the tension in the leach and keeps your sail flat. conventional wisdom has us adding topping lifts to add twist which also adds forestay tension. Not to mention the fouled toppinglift/spreader routine…
Now if we attach the jib club and sail to the same point on the deck at the foremost point on the club and tack of the jib, Like big boats, we are left with too much twist. big boats have blocks and winches and such and can pull down and back when they sheet in and move stuff around to create the sail shape they want. with no tension in the leach our sail shape sucks…
If the forestay is attached to the leading of my sideways “u” and a line is drawn down to the deck and the deck is attached to the leading edge of the bottom of of my sideways “u” via conventional methods (rack, swivel, hook, ect) the “u” has become part of the forestay.
the top leg of the U has a sail attachment point and a pivot point (up/down only) for the solid adjustable vang. the bottom leg of the U has a pivot point for the boom (up/down only), and the deck attachment point.
with out sails on and the fitting and boom/vang in place the unit should swing pretty easily form side to side… with the forestay tensioned and the swivel to the deck.
If we put the sails on and attach the clew to the end of the jib club via conventional methods. we should be able to raise and lower the clew via the vang adjustment. just as we would via the topping lift…Just like we do on the main sail…Right???Or amI missing something
As I said though, the Forestay tension will be the key to this. Too little and you have no control over the leach… too much and you induce mast bend…
Manny’s radial fitting does not rely on forestay tension. But is a much more involved build…
I think that, because your sideways U fitting is suspended along the length of the forestay, when the vang is resisting the clew from lifting, the fitting will tend to rotate the line of the forestay fore and aft, thereby increasing the tension on the stay. Will that added tension be enough to hold down the clew? Considering the leverages involved, my guess is no. You might even add enough tension to break the stay or to rip out an attachment point.
You may be better off by making a hinge type of fitting, where a substantial diameter rod (maybe 3/32" or 1/8") is anchored to the jib rack where the U piece can swivel on the rod. The rod should be at least 3" long. You then attach the forestay to the top of the rod. You’ll also need to prevent the U piece from climbing up the stay.
Without doing any testing, I believe that will help increase the downward pressure of the vang without putting undue strain on the rigging.
Manny uses a pivot on the deck and some screw adjusters so the jib/vang/boom swings separate from the forestay and his appear to be very close to a permanent attachment on the deck…
I’m trying to simplify manny’s design…
Manny’s also looks to be a but difficult to remove for transportation. remember we are talking about an ec12…
I did cut some of the U pieces and I’ll bring in some nice drill bits for for the drill press tomorrow…
I’m going to try to make manny’s, but I don’t think I can do it…( so much for confidence) I dont’ think I have all the tools to do it properly…
Marc
This is what I was thinking but give it a shot. Just cobble up a working one, don’t worry about pretty. While you’re doing it you may hit on something.
Here is a jib club for your interest.
This one is designed and made by PJ Wiles in England.
It is for sale if you want to purchase it.
US $30 plus postage and its yours.
The biggest challenge with any that you use is to ensure the alignment of the forestay with the attachment point on the mast.
I have some other drawings of various models that may take a bit of finding if your interest continues.
Don`t hold your breath but I will have a dig around in my “files” LOL :lol:
I saw that one from the UK site. that’s kinda of what I’m trying to semi replicate but on a much simpler scale… how much does that fitting weight…it just looks massive. FWIW Id consider buying it from ya. but it does not appear to be real easy to remove the sails/rig from on a regular basis…plus the postage from NZ to USA woul be as much as the price youa re charging…