Inexpensive gooseneck and vang fitting

Rcsailing.net Technology Discussions
1

Here is a very inexpensive fitting that works very well. The cost is about $2. It is very low friction and is very accurately aligned.

I sail an IOM and have three rigs. I use alluminum arrow shafts for the booms that I get from a local sporting goods shop. I buy clearance items or damaged items so the cost is about $1 per boom to free.

The parts for the fitting described cost $6 but provides fiittings for three rigs.

This model consists of a brass tube that slips over the mast (the mast band) locked in place by a small screw.

Soldered to the band is a brass tube.

Inside the brass tube is a second brass tube that floats to act as a bearing.

Inside the floating tube is a 1/16th wire that is bent at the top into the boom and bent at the bottom to attach to the vang.

The sizes start with the 1/16 wire.

Get a 12 inch brass tube that slips over the wire (the bearing tube)

Get a 12 inch brass tube that slips over the bearing tube.

Get a 12 inch brass tube that slips over the mast.

To make it accurately, solder the outer tube to the mast band while still at 12 inches. Then cut off the require length (usually about 55 to 60 mm). You can get three assemblies off one section.

Cut the bearing tube to length. Slip into the mast tube assembly.

Bend the wire into the boom, slip through the bearing tube, and then bend up toward the vang and bend a loop on the end.

I like the lever style vang now that I have used it a few weeks. But it needs a 3:1 purchase to give sufficient fine tuning.

Of course this gooseneck system can be used with a turnbuckle.

2

I gotta ask - what’s wrong with two interconnected screw eyes. One into the mast and vertical aligned, and one into end of boom and horizontal aligned?

I recall this discussion in the past, but don’t remember the final outcome.

Theory (based on mathematics) is that each screw eye has a circular cross section. Since there can only be one point in a circle that touches a surface (or a single point) of another circular section, it has the least friction of movement than any other type of gooseneck, whether a long pin inside a brass tube like John’s - or whether a small screw through the center of a ball-end steering fitting.

Of course it doesn’t “Look as cool” as other ideas or methods, yet seems to work OK.

3

Hi Dick,

Scew eyes are a simple system but have their limitations. I think they work ok with wooden masts and booms

I would not want to use a screw eye for a vang attachment to the bottom of the mast unless it was through drilled and bolted. The standard Soling 1M suffers from this problem in stronger winds. The screw eye rips out of the mast and sometimes the boom too.

I don’t think the screw eye works as well with alluminum masts and spars. Again the vang needs to be through bolted to handle the loads. The boom requires an endplug to receive the screw thread. (I don’t have a lathe to machine parts to fit)

The other problem with screw eyes is that the boom works in compression and the vang in tension. The geometry of the vang attachment in tension works fine. However for the boom working in compression, the eye can move around its bearing surface at random and change its geometry.

The idea behind my system is that it is strong and cheap. It requires no special machining. And it works. . .it has surprisingly low friction.

Just to give this item a context, I race in the IOM class. I am retired and live on a fixed income. I could buy a Sail etc vang fitting at $28 and a boom kit for about $25. (If I wanted the ball bearing fitting for my A rig, that’s almost $80 for the goosneck/vang fitting alone). So close to $80 for a boom and gooseneck times 3 for the three rigs. I need to compete with this at a lower price point. I need a high performance fitting that is low friction consistent geometry and provides repeatable settings. The fitting that I have developed does this for three rigs for under $10 total. I’m happy.

4

18 years ago I told my wife I NEEDED a lathe/milling machine and that I would save lots of money by making my own stuff. I am now obligated to make things in the most complex manner I can think of. :D:D And it’s fun. That said a lot of times a bent wire works as well if not better than a milled part. You can re-adjust a bent wire with a pair of pliers, not usually so with a milled part.
Don

5

Here is my version of an inexpensive gooseneck fitting.
It is made with Tamiya model car ball joints attached to a tube similar to the previous unit shown.
The version illustrated was made for a Micro Magic but they will work for everything from a FOOTY up to an AC15.

6

John, I think you are right “Screw eyes are a simple system but have their limitations.” they work fine on the vang under tension but are bad for a goose neck under compression. Here are a couple of pictures of my new setup for my Soling 1M. The bolts through the mast are adjustable so you can get more bag in the sail down wind. The red rods are knitting needles, good aluminum and cheep, $2 for 2 of them 12" long. And yes I have a lathe, it’s old, flat belt drive. I think I have about $3 in the whole mess.
john

7

Very nice work John! I was considering something similar to get the axis adjustment but I can’t bring myself to drilling a hole right through a CF mast. I guess I should try it and if it breaks, it breaks.
Don

8

Don on the carbon fibber mast I would put a wad of tissue inside the mast about an inch above where you are going to drill the top hole and fill it with epoxy, then drill your holes, this will keep the mast from crushing when you tightening the bolts. I have drilled many holes in carbon masts before with no problems,
john

9

John,
Very nice looking setup. Where did you get the knurled turnbuckle knob fitting? Is it easy to locate a reverse threaded tap? I sort of doubt the local hardware store has such a tap in stock.
Bill

10

I have used the old plumbers trick. and used a ball of bread. once done and set up. you can dribble some water into the hollow end of the mast, and the bread comes right out…I’ll have to look for pics of my vang/goosneeck.

I used a brass tube1" long with two shouldered wheel bearings on each end and then used a hollow tube inside the bearings. the inner tube extends about 1/4-1/2 inch above and below the bearings. crimp the ends of the inner tube flat and drill a small hole in each end. on each end I use a dubro #302 threaded rod ends. one goes into the boom, and the other for the vang. for the vang I use a 4" long titanium http://www.lunsfordracing.com/mm5/merchant.mvc turnbuckle, and for the vang attachment on the boom I used a nylon quick link which I reverse thread to accept the reverse thread of the turnbuckle. I drilled a small home in the center of the turnbuckle and put a small pin to aid in turning the turnbuckle to adjust.

I then lashed the assembly to the mast and then coated the lashing with epoxy. very smooth, and very sturdy. probably about 20 bucks in parts with enough to do two assemblies provided you buy an extra pair of bearings

I’ll post some close ups when I get home if any one is interested.

11

Yes please, I always want pictures.
Don

12

You know, out of all this there are are only a couple of things about goosenecks I might use. But there are a ton of hints about using material that are what makes these forums priceless. Great stuff.

-Barry

13

Bill, I make my own knurled turnbuckle knobs, I get my left hand taps & dies from McMaster-Carr I use 6-32 and a #5 knitting needle.
john

14

John
How do you hold the needles for tapping without scratching the anodizing? Do you have a soft faced vice or something?
Thanks
Don

15

Don I do it all on the lathe, the chuck I have has smooth jaws, I chuck the needle then drill and tap, I put the lathe in back gear for the taping and hold the tap in the Jacobs chuck on the tail stock and let it slide free. For the turnbuckle I turn the needle down to size on each end then hold the die in the lathe chuck and hold the center of the needle in the Jacobs chuck on tail stock and let in slide, put lathe in back gear and lots of oil.
Hope this helps John

16

sorry it took so long to get the pics back…

17

here is a super close up

I have this vang/goosneck on both Vics and my Soling as well

18

Thanks Marc
Looks good but it also looks like your cunningham will loosen on one tack and tighten on the other. Is there something I’m not seeing? What do the other lines that wrap around the mast do?
Thanks
Don

19

Hi Don,

I think Mark is using something like the self adjusting cunningham as shown on Lester’s site.

http://www.onemetre.net/Build/Downease/Downease.htm

20

don

the cunningham wraps around the mast to the adjustment ring and then back around the mast, then back to the ring and then tied off.

because my goosneck/vang is offset from the mast and since I go from the mast to the adjustment ring more than once, when the boom goes left or right it will loosen the Cunningham almost equally with the boom on either side when running down wind.

if I only went around the mast on one side and then stopped, you are correct, on one tack it would loosen, and on the other it would tighten…

on the other end of the ring, is a bowsie so I can adjust the tension even further.

The off set of the gooseneck is what makes this work. IMO…without the offset, you wont get as much tightening/loosening as the boom rotates form one side to the other…