Need to add a tang for hoisting

[Madwand]

I wanna add one of these to the upper end of my mast for hoisting the water toys on and off the Catalina 30 foredeck, <100 pounds at a time. Maybe hang a swing from it.

The jib halyard is the only thing in front of the mast, so I don't even have a spare for safety line when going aloft.

I been reading aluminum vs. stainless til my head hurts. I'd prefer to get an aluminum tang and use aluminum rivets even though the shear strength is 300 pounds vs. 1300 pounds. So I can't find a tang that's made of aluminum, or at least says in the description, maybe they don't make it. I have a regular shop type riveter, but not one of those according types I see people using. I don't want to tap and thread, don't even know if my mast is thick enough.

So if I can't get an aluminum tang, I'd just use SS rivets and go through the motion of slopping some goo on them.

So are there aluminum tangs?
Should I not use aluminum rivets?
Can I use my normal riveter, either way?
Do I have to tap and thread?
If I have to use dissimilar metals, I don't understand how smearing some tefgel on screws works once the threads bite into the aluminum. Or is just a minimizing effect where you know you're still gonna get corrosion?
And lastly, I'm guessing you want it high as opposed to halfway up, for a better working angle, but using twice or more line?

[AiniA]

No way to add a second jib halyard or even a spinnaker halyard. Would be very simple to do and stronger than a tang. Don't know how Tefgel works, but it does work. Just removed some fitting from my mast that I had added and used Tefgel. Came out very easily. Ones that do not have TG are like they are welded in place.

[Madwand]

I do not think so, I think it is single sheaves and inside the mast. Unless it's just something I don't know about, adding halyards...

Maybe I shoulda asked if there's extra sheaves up there?

[Stumble]

I would much rather add a second spin halyard than add a tang. Even if you have to cut a larger sheave box it would be preferable.

[Jim Cate]

I've seen plenty of Catalina 30s with spinnakers flying, so I expect that your masthead fitting has some sort of bale for a spinny halyard block. Using that would be the best solution by far.

Jim

[Madwand]

The guy who installed my furler tells me that he thinks there's another sheave up there. If that's the case, is it supposed to be a simple matter to drop another line? I'll bet it's not...

[Jim Cate]

Originally Posted by Madwand

The guy who installed my furler tells me that he thinks there's another sheave up there. If that's the case, is it supposed to be a simple matter to drop another line? I'll bet it's not...

Yes, many masthead sheave boxes have two pairs of sheaves. However, for hoisting things from alongside, using a block hanging free from the bale on the masthead (as in a spinnaker halyard) will work better and with less chafe.

In the distant past, when I had a Yankee 30 and a ~10 year old son, he used to love to swing from a spare jib halyard which ran through the normal sheave in the masthead. A few sundays worth of that game chafed the halyard to an unusable state. Grrr...

Jim

PS And someday you might want to fly a spinnaker or genaker, and having the halyard would be cool...

[Madwand]

Originally Posted by Jim Cate

However, for hoisting things from alongside, using a block hanging free from the bale on the masthead (as in a spinnaker halyard) will work better and with less chafe.

I don't know enough to know what that is (don't know how a spinnaker is rigged), but how is it different than the tang and pulley I want to add under my restrainer, other than 2 feet higher? Is that as simple as shackling a pulley to a hole?

[Jim Cate]

Originally Posted by Madwand

I don't know enough to know what that is (don't know how a spinnaker is rigged), but how is it different than the tang and pulley I want to add under my restrainer, other than 2 feet higher? Is that as simple as shackling a pulley to a hole?

Well, without having a look at your specific masthead, I can't answer that. But most such devices have some sort of fitting on the forward side for doing just that: shackling a block for a spinny halyard.

The difference is that it is VERY strong, and the riveted tang will be highly suspect in terms of strength. For me, anything that I might be hanging from personally or that I might want to lift something heavy into the air above me or other persons must be damn strong. This precludes anything relying upon pop rivets, especially aluminium ones that can be set with a typical DIY gun.

Can you get a telephoto oic of your masthead, taken from the bow or nearby dock... a pic that shows some detail of construction? That would help us help you.

on edit: here's a link to a drawing of a Cat 27 masthead. Yours is probably similar, and you can see where the spinny halyard block goes.

https://goo.gl/images/n1cfLo

Jim

[Madwand]

I have a Nikon 70-300mm*lens I could try to get some pix with. Don't go to the boat til next weekend though. That would be nice if there were a hole up there I could use.

[Benz]

The reason you're not finding aluminum tangs is that an alloy tang as strong as a SS one would be very thick. If you wind up using a SS tang, by all means drill and tap and use SS machine screws. Your mast is thick enough, and you'll wind up with a far more reliable setup than pop rivets, which there's no excuse for, ever.

Tef-gel works because it thinly coats the surface and prevents metal-to-metal contact. I'd butter up the back of the tang as well, so it's riding on a thin smear of tef-gel between it and the mast. A very little goes a long way, but it is almost miraculous in it's effectiveness.
Ben
zartmancruising dot com

[Madwand]

Originally Posted by Jim Cate

Can you get a telephoto oic of your masthead, taken from the bow or nearby dock... a pic that shows some detail of construction? That would help us help you.

This seems to be what you're asking me if I have
https://www.catalinadirect.com/index...crane-c-30.cfm
So Catalina will sell me one if I don't...Too bad I have no idea what that would involve to install. Seems to be a lot of crap up there that would be in the way, even though they make it sound simple.

[Madwand]

Originally Posted by Benz

Your mast is thick enough, and you'll wind up with a far more reliable setup than pop rivets, which there's no excuse for, ever.

Thanks, good to know.

[Jim Cate]

Originally Posted by Madwand

This seems to be what you're asking me if I have
https://www.catalinadirect.com/index...crane-c-30.cfm
So Catalina will sell me one if I don't...Too bad I have no idea what that would involve to install. Seems to be a lot of crap up there that would be in the way, even though they make it sound simple.

Did you view the link I added to my last post ? I don't think you will need the add-on crane shown in your link.

Jim

[Madwand]

Gotcha, I hadn't seen the edit. So if you look at this page
https://www.catalinadirect.com/index...sting-c-30.cfm
This is a newer model, but at the bottom are some pix of an older corroded one which I think is mine, although I don't really recognize it from my one trip to the top. But if you are referring to the pin between the two "ears," then I follow what you're saying.