Chasing Elegua

[Panope]

Good to hear that the Wichard SS hanks worked well. I like the much larger opening these have compared to the piston hanks. I might use them on a Yankee (yet to be built) for use with the new bowsprit.

....also good to hear of the successful use of "soft hanks". I might go that route for another sail project: a huge, ancient, but never used drifter (got for free) that will be cut down. This sail will not see more than 10 knots so perhaps even Velcro hanks might be appropriate (with a soft shackle at the head).

 

[Elegua]

So here is the offending vang fitting. The top two screws backed themselves out and the fitting itself was flexing. I screwed them back in with a no 1 philips with as much torque as I could muster while offshore and they seem not to have moved. Seems like a robust unit until you realize it’s actually a small lever arm. Solutions range from - it’s screwed back in, leave it, to screw them back in with some red locktite to use bigger/better fasteners and put a support behind the fitting so it’s no longer a lever arm. Not a huge mainsail - about 360sq ft. Attaches to a rigid vang.

 

[accnick]

So here is the offending vang fitting. The top two screws backed themselves out and the fitting itself was flexing. I screwed them back in with a no 1 philips with as much torque as I could muster while offshore and they seem not to have moved. Seems like a robust unit until you realize it’s actually a small lever arm. Solutions range from - it’s screwed back in, leave it, to screw them back in with some red locktite to use bigger/better fasteners and put a support behind the fitting so it’s no longer a lever arm. Not a huge mainsail - about 360sq ft. Attaches to a rigid vang. View attachment 557560

The whole arrangement looks iffy to me. Vangs are under a lot of eccentric loading. That bracket could probably flex quite a bit, since it looks like it is "free-standing", rather than fitting flush to the mast What I see does not look like the way a sparmaker would make a lower vang fitting.

Is the back of your mast flat or rounded?

 

[Jud - s/v Sputnik]

Good to hear that the Wichard SS hanks worked well.

For my drifter I had made last year, I went with the Wichard bronze hanks. Sailmaker thought going with stainless wasn’t necessarily “worth it” - I.e., not worth the extra cost. (I had wanted stainless.). Just FYI, Wichard stainless one-hand snap hooks seem to be double the cost of their bronze ones.

 

[Beer fueled Mayhem]

My vang attachment point is riveted in. Big rivets. Thought being that helps with the cyclic loading. I'm no engineer though. Read about the rivet thing in a book.

 

[Jud - s/v Sputnik]

So here is the offending vang fitting. The top two screws backed themselves out and the fitting itself was flexing. I screwed them back in with a no 1 philips with as much torque as I could muster while offshore and they seem not to have moved. Seems like a robust unit until you realize it’s actually a small lever arm. Solutions range from - it’s screwed back in, leave it, to screw them back in with some red locktite to use bigger/better fasteners and put a support behind the fitting so it’s no longer a lever arm. Not a huge mainsail - about 360sq ft. Attaches to a rigid vang. View attachment 557560

Are those drilled and tapped directly into the mast, or into rivnuts?

 

[Elegua]

The whole arrangement looks iffy to me. Vangs are under a lot of eccentric loading. That bracket could probably flex quite a bit, since it looks like it is "free-standing", rather than fitting flush to the mast What I see does not look like the way a sparmaker would make a lower vang fitting.

Is the back of your mast flat or rounded?

Beveled. The mast is one of those isomat NG sections. The fitting is free standing making it a nice lever-arm to pry the fitting off the mast. I’m pretty sure it’s aftermarket when the po twice removed added the rigid vang. Looks vaguely like a vangmaster fitting.

 

[Elegua]

Are those drilled and tapped directly into the mast, or into rivnuts?

No rivnuts

 

[Max Rockatansky]

WRT snap hanks: it was my experience that the snap hanks snagged things like line and spinnaker so I changed them to soft dogbone hanks. To disclaim, the boat was raced, so the situation may well make the difference

 

[accnick]

Beveled. The mast is one of those isomat NG sections. The fitting is free standing making it a nice lever-arm to pry the fitting off the mast. I’m pretty sure it’s aftermarket when the po twice removed added the rigid vang. Looks vaguely like a vangmaster fitting.

I did a quick online search for vang fittings last night, but haven't found anything definitively right for your application. Looking at Quikvang specs for your size boat, it calls for a gooseneck pin that is 5/8", for starters.

Post a couple of more detail photos if you can. Is there any flat at all across the back of the mast? I remember those Isomat sections as being a bit odd compared to what was being done in the US at that time, where a D-section was more common.

 

[Ajax]

Hm. An interesting problem. Rivnuts or red locktite.

 

[Elegua]

I did a quick online search for vang fittings last night, but haven't found anything definitively right for your application. Looking at Quikvang specs for your size boat, it calls for a gooseneck pin that is 5/8", for starters.

Post a couple of more detail photos if you can. Is there any flat at all across the back of the mast? I remember those Isomat sections as being a bit odd compared to what was being done in the US at that time, where a D-section was more common.

The isomat sections are a bit unique. The French copy no one and no one copies the French.

Before departure I did some work on the gooseneck to remove some play with delrin bushes and make it easier to lash the tack. The sunbrella boot is just a bodge to keep the Sun off the rubbaweld. Mast is spartited.

I was wondering if having someone make a backer out of g10 or delrin to close the space behind the fitting and then improve the fasteners.

 

[TwoLegged]

For my drifter I had made last year, I went with the Wichard bronze hanks. Sailmaker thought going with stainless wasn’t necessarily “worth it” - I.e., not worth the extra cost. (I had wanted stainless.). Just FYI, Wichard stainless one-hand snap hooks seem to be double the cost of their bronze ones.

Why would you prefer stainless?

I wouldn't want shiny glisteny stuff on a luff I'd be watching for sail trim. Dulled bronze seems to be to preferable.

 

[Elegua]

In the meantime, between boat stuff…

 

[bgytr]

So here is the offending vang fitting. The top two screws backed themselves out and the fitting itself was flexing. I screwed them back in with a no 1 philips with as much torque as I could muster while offshore and they seem not to have moved. Seems like a robust unit until you realize it’s actually a small lever arm. Solutions range from - it’s screwed back in, leave it, to screw them back in with some red locktite to use bigger/better fasteners and put a support behind the fitting so it’s no longer a lever arm. Not a huge mainsail - about 360sq ft. Attaches to a rigid vang. View attachment 557560

Looks like trouble to me.
As a retired structures nav arch, I'll give a qualitative assessment without running any numbers. The top screw and bottom screw are going to take the bulk of the load. The top of the bracket will be pushing forward on the screw, and the bottom of the bracket will be pulling aft on the bottom screw. The bracket at the bottom screw has very little shear area to absorb that load, it is very close to the edge.
Looking down on the bracket from above, I would expect the top of the bracket wants to push forward, and the bottom of the bracket wants to pull aft. Since the bracket runs more side to side than fore and aft, the bracket material being relatively thin plate will flex because there is not much to prevent it from doing so.
When you are reaching and the boom is eased out, there will be an athwartship component to the flex that will add to the loading.
It looks like a rigger without much engineering background backfit it without a consult to a structures person.

 

[Elegua]

Looks like trouble to me.
As a retired structures nav arch, I'll give a qualitative assessment without running any numbers. The top screw and bottom screw are going to take the bulk of the load. The top of the bracket will be pushing forward on the screw, and the bottom of the bracket will be pulling aft on the bottom screw. The bracket at the bottom screw has very little shear area to absorb that load, it is very close to the edge.
Looking down on the bracket from above, I would expect the top of the bracket wants to push forward, and the bottom of the bracket wants to pull aft. Since the bracket runs more side to side than fore and aft, the bracket material being relatively thin plate will flex because there is not much to prevent it from doing so.
When you are reaching and the boom is eased out, there will be an athwartship component to the flex that will add to the loading.
It looks like a rigger without much engineering background backfit it without a consult to a structures person.

Very likely. What’s a good fix?

 

[Ajax]

@Elegua what are you doing down there besides fretting about the boat?

Dining at any exciting local restaurants? Hiking the national parks? Meeting the other cruisers? Have you gone swimming? What have you done for recreation?

 

[bgytr]

Very likely. What’s a good fix?

I will get back later today with a sketch.. out running some errands.

 

[accnick]

Very likely. What’s a good fix?

Short of building a new bracket that fits against the mast properly, you might even consider filling the gap between the bracket and the mast with Spartite. That might or might not be rigid enough for the job.

It really does not look like a well-thought-out fitting design.

You need to figure out if the screws are still gripping or not. Most mast walls are pretty thin for direct tapping of machine screws.

Best case scenario, and the mast is a bit thicker so that you have enough threads, and the threads aren't stripped, I would use blue Loctite on the threads of the machine screws, plus completely filling the gap behind the fitting. If the screws aren't holding and the mast wall is too thin, rivets are probably the best solution.

In any case, I would pull that fitting off and examine it carefully for signs of bending or cracking. Movement or flexing of the fitting is your enemy. Gaps exacerbate that, since all the loading comes on the fasteners as point loads.

On the plus side, you are probably in a location where you can get access to all the marine trades, even if it isn't convenient.

 

[Ajax]

You need to figure out if the screws are still gripping or not. Most mast walls are pretty thin for direct tapping of machine screws.

Hey, you just sparked a thought- Could he through-bolt the bracket through the existing holes if they line up? (I still advocate filling the gaps with a solid material)