strange way (for me) to attach cap shrouds

[mait]

Hi,

Has anyone seen such a way to attach cap shrouds to the mast?
The wires enter the mast just 50-60cms below the top of the mast, through the slots cut into sides of the mast. Then continue INSIDE the mast to the very top where they are attached to the long bolt that goes through the mast.
Is this something to consider a problem to be addressed or common practice?

The mast is unstepped at the moment, the boat is under refit.

The boat is OE36 from 1976, double spreader mast by Swedish company Skarven that seems to be out of business.

The previous owners have modified the rigging extensively. OE36 has a conventional mast-top rig with inline spreaders by design.
This boat has its mast step moved forward about 40cms (I suspect it was done during production already), and has swept-back spreaders, but is still mast-top rigged. It had been rigged as Bergstrom/Ridder rig before the previous owner. https://en.wikipedia.org/wiki/B%26R_rig
The guy who sold me the boat redesigned the rig to its current design. That is mast-top rig with double swept-back spreaders. See attached photos

[Manateeman]

Never see it before. Is the wire is showing damage where it enters the slot?
What is your concern exactly. If you would feel more comfortable with a more traditional bolt / exterior tang attachment, I think a good rigger could make the switch. Is their access to inspect the uppermost wire to fitting connection?
If not, is inspection your concern?
Mark

[mait]

Originally Posted by Manateeman

...Is the wire is showing damage where it enters the slot?
What is your concern exactly...
Mark

The wire itself dosn't show any damage. But the slots cut into the aluminium have somewhat rough edges and it looks like the wires have chewed the edges of these holes. I am not sure the slots allow the wires to pass through without touching the sides of the slots. Considering the movement of the mast top (imagine tensioning / untensioning backstay etc) I tend to think connecting the shrouds outside of the mast would make more sense.
I just try to understand what was the reason of this setup. Myabe there is a good idea behind the design that I just do not get.

[Bill O]

Originally Posted by Manateeman

Never see it before. Is the wire is showing damage where it enters the slot?
What is your concern exactly. If you would feel more comfortable with a more traditional bolt / exterior tang attachment, I think a good rigger could make the switch. Is their access to inspect the uppermost wire to fitting connection?
If not, is inspection your concern?
Mark

Agree w/Mark that it wouldn't be too difficult to go back to an exterior tang.

Hard to tell if the mast is raked/bent back in the pic. If it's not raked/bent, there maybe too much pressure on the slot and on the wire angled back to the swept back spreader tips. Could go up the mast and run a line from the mast head side bolt to the tip of the spreader to see if it could be a concern.

I've only rigged/designed a couple of masts, so no expert. When I did my first mast I consulted a NA that specialized in racing boat masts to check over my calculations.


Edit: I see your rig has a back stay. The later gens of the B&R rig eliminated the back stay, so yours must be an early gen?

[mait]

Originally Posted by Bill O

...If it's not raked/bent, there maybe too much pressure on the slot and on the wire angled back to the swept back spreader tips...

Edit: I see your rig has a back stay. The later gens of the B&R rig eliminated the back stay, so yours must be an early gen?

That's what I'm thinking, too. There may be too much pressure on the edges of the slot. The mast is not 100% stationary, there is some movement. And adjusting the backstay for different bends will position the wire in the slot differently. So better to change to external tangs.
Now - should the tangs be fitted to the very top where the bolt is and where the cap shrouds aere attached now? Or to the point where the slot is now?

I think the B&R rig was early gen, it looks like the backstay has been there since the very beginning. I got the boat with its current rig with conventional shrouds only, no reverse diagonals.

[seandepagnier]

in theory this is superior as it reduces windage.

[NSboatman]

This is not an unusual way to rig cap shrouds- very common on Isomat masts of the ‘80’s and ‘90’s. It is intended to clean up the congested area around the mast head, reducing tangling opportunities for spinnakers and large free-flying foresails and the like; and it does marginally reduce wind age (although I challenge anyone to be able to quantify by how much!).

It is sort of counter-intuitive to see the cap shrouds bend slightly on the edge of the hole- and I have to admit that when I saw it first I didn’t like it either- but after many 10’s of 1000’s of miles with a rig like this I’ve seen no evidence of long term damage or issues.

Keeping the rig tight and preventing it from moving as much as possible is a good thing anyway, and probably even more important in this case.

[Bill O]

Originally Posted by mait

That's what I'm thinking, too. There may be too much pressure on the edges of the slot. The mast is not 100% stationary, there is some movement. And adjusting the backstay for different bends will position the wire in the slot differently. So better to change to external tangs.
Now - should the tangs be fitted to the very top where the bolt is and where the cap shrouds aere attached now? Or to the point where the slot is now?

I think the B&R rig was early gen, it looks like the backstay has been there since the very beginning. I got the boat with its current rig with conventional shrouds only, no reverse diagonals.

I'll assume you mean movement in the mast to be the bendy fore/aft movement. Trying to wrap my head around the design/concept of the rig on your boat.
The swept back spreaders in a true B&R rig are to eliminate the back stay and put a pre-bend in the mast. Yours still has the back stay so you can put more bend in it, which also possibly changes the wire angle in the slot potentially causing wear on the wire/mast.

My question is do you actually see much benefit in changing the bend or is the set pre-bend good enough allowing the wire to sit in the slot evenly?

To NSboatman's point, has the rig been up for thousands of miles w/o an issue? To that same point, you can't see the terminal ends of the uppers to know if there is an issue. IMO I would want them outside to visually inspect them also not have the wire rub on the mast slot.

Also from the limited info, I do not know how/where the the uppers are terminated in your mast. I don't see any external bolts or fittings except the mast head bolt. In your second pic (of a boat next to yours?) w/a similar slot, it has a fractional rig and a fitting lower presumably terminating the uppers there also.

Again more spit balling w/limited info, would put an external tang off the mast head boat (since you do not have a fractional rig). This would give you a less obtuse angle to the spreader tip and allow you to inspect the upper ends. Also going to the mast head bolt, you would eliminate the need to a internal compression sleeve on the bolt if you dropped it lower (not hard to do, but one less thing to do).

If it were my boat, first off would discuss w/a NA (that specialized in designing rigs) to go over possible changes that you want to do.

[Bill O]

Trying to look at your boat more and came across an OEYC in Scandinavia. Sorry couldn't read it to see if it had any helpful info about your boat.


There is an interesting back story about the designer of your boat, Olle Enderlein. Besides the OE boats he may have had a hand in some early Hallberg-Rassy designs as well.

[Cpt Mark]

Yes these are on boats. Caliber 40's come to mind. No big deal

[Bill O]

Never seen a Caliber w/swept back spreaders nor a B&R rig. Can you show an example of one?

[David B]

Originally Posted by mait

Hi,

Has anyone seen such a way to attach cap shrouds to the mast?
The wires enter the mast just 50-60cms below the top of the mast, through the slots cut into sides of the mast. Then continue INSIDE the mast to the very top where they are attached to the long bolt that goes through the mast.
Is this something to consider a problem to be addressed or common practice?

The mast is unstepped at the moment, the boat is under refit.

The boat is OE36 from 1976, double spreader mast by Swedish company Skarven that seems to be out of business.

The previous owners have modified the rigging extensively. OE36 has a conventional mast-top rig with inline spreaders by design.
This boat has its mast step moved forward about 40cms (I suspect it was done during production already), and has swept-back spreaders, but is still mast-top rigged. It had been rigged as Bergstrom/Ridder rig before the previous owner. https://en.wikipedia.org/wiki/B%26R_rig
The guy who sold me the boat redesigned the rig to its current design. That is mast-top rig with double swept-back spreaders. See attached photos

Just the fact that you can't inspect the end of the shrouds is enough of a reason to reject this system. Then there is the chafing/abrading issue at the exit slots.

I would not be happy if it was my boat.

[mait]

Thank you all for your responses!
I think David B has made a perfect conclusion - that's a good reason to redo the system.

On another hand it is nice to know that the system has been used by Isomat and not something PO has made up himself.

And yes, OE36 is designed by well-known (at least in Sweden) Olle Enderlein. He has designed a lot of boats, among them some HRs. OE36 was his flagship that unfortunately had a sad production history.

[Boatyarddog]

Originally Posted by mait

Thank you all for your responses!
I think David B has made a perfect conclusion - that's a good reason to redo the system.

On another hand it is nice to know that the system has been used by Isomat and not something PO has made up himself.

And yes, OE36 is designed by well-known (at least in Sweden) Olle Enderlein. He has designed a lot of boats, among them some HRs. OE36 was his flagship that unfortunately had a sad production history.

I think it's this arrangement.
https://www.google.com/search?client...w=1024&bih=649
Internal stem ball and internal tangs.
Remove mast head to service these.
More a guess.
Boatyarddog

[MicHughV]

I can't see this as a good idea.

1)Firstly it induces a bend on the wire, and since the wire is made up of several strands, it means some wires will experience more load than others.
2) At the very least, there should be some kind of stainless " sleeve" in the mast aperture. This would protect both mast and wire against potential frictional forces, which could wear out the mast or wire or both..
3) I don't see how the wire fitting is attached to the bolt. It would require some type of terminal end fitting. How is this fitting attached? the masthead cap would need to be removed.
4) How is this wire (and end terminal) inspected for wear, etc, if you can't see it or inspect it ??
5) I can think of several more things, but what's the point.

I've never seen such a thing, and question it's validity. Surely no nautical architect would come up with such an idea.