Upgrading rigging from 8mm to 10mm

[Mateolessa]

Hello team,

The time has come to replace the standing rigging on a Hans Christian 38. Getting the boat ready for offshore and passage making i am debating making the switch to 10mm

What is the breaking strength and weight difference between 8 and 10mm cables?

How will this affect the vertical center of gravity?

The current rigging is norseman 8mm on 5/8 turn buckles. I would switch to 10mm pressed fittings on the same turn buckles.

I know that more weight higher (bigger cables) is supposed to affect the motion, vertical center of gravity and therefore affect the righting in case of capsize but how much would this affect a 30 000lbs heavy displacement boat like the full keel Hans Christian?

I feel like if there were to be a rigging failure it would come from a connections failure and not the cable itself but would it be wise to change to bigger cables or is 8mm plenty strong enough for circum navigation?

Thanks

[s/v Jedi]

Originally Posted by Mateolessa

Hello team,

The time has come to replace the standing rigging on a Hans Christian 38. Getting the boat ready for offshore and passage making i am debating making the switch to 10mm

What is the breaking strength and weight difference between 8 and 10mm cables?

How will this affect the vertical center of gravity?

The current rigging is norseman 8mm on 5/8 turn buckles. I would switch to 10mm pressed fittings on the same turn buckles.

I know that more weight higher (bigger cables) is supposed to affect the motion, vertical center of gravity and therefore affect the righting in case of capsize but how much would this affect a 30 000lbs heavy displacement boat like the full keel Hans Christian?

I feel like if there were to be a rigging failure it would come from a connections failure and not the cable itself but would it be wise to change to bigger cables or is 8mm plenty strong enough for circum navigation?

Thanks

You have a monohull and the rigging size is determined by the force required to heel the boat. Unless you see evidence of rigging failures at the same boats, there is no need to upgrade the size.

Also, your Norseman fittings are superior over swage fittings. I recommend you keep them after a close inspection shows no cracks.

There is one other option: you can switch to 8mm (5/16”) Dyform wire which is the same diameter but around 20% or so stronger. But it’s also 20% heavier.

[The Yacht Rigger]

To answer the weight question, which is pretty significant, keeping in mind the swage fittings will be heavier too.
in 1x19..
8mm = 21lbs per 100' - Break load - 11858lbs
10mm = 32.8lbs per 100' - Break load - 18527lbs

As Jedi said, your rigging was likely designed with plenty of margin for error, unless you have heard of reported failures within the safe working life of this vessels rigging, there's really no reason to beef it up. You'd be better off just spending that money on other safety equipment.

If you are dead set on upgrading, you could look at 3/8" wire which is slightly lighter than 10mm at 30lbs per 100' and a break load of 17076 lbs, but even that is overkill IMO.

Also echoing what Jedi said, 8mm compact strand wire is 23.2lbs per 100', and has a break load of 13530. It is less stretchy than 1x19 so would result in a stiffer rig, but is more expensive than 10mm 1x19.

[Jammer]

Originally Posted by Mateolessa

Hello team,

The time has come to replace the standing rigging on a Hans Christian 38. Getting the boat ready for offshore and passage making i am debating making the switch to 10mm

Why would you do something like that?

What is the breaking strength and weight difference between 8 and 10mm cables?

https://www.fisheriessupply.com/wire-rope1-316-ss-1x19-strand-wire-rope/1213778x3x

About 0.1 pounds a foot. You can look up the breaking strength difference yourself.

How will this affect the vertical center of gravity?

Between the cable and the fittings you would add at least 25 pounds aloft, which is, well, a substantial amount.

The current rigging is norseman 8mm on 5/8 turn buckles. I would switch to 10mm pressed fittings on the same turn buckles.

If the current rigging is shot, there's a good chance that the turnbuckles are shot.

I know that more weight higher (bigger cables) is supposed to affect the motion, vertical center of gravity and therefore affect the righting in case of capsize but how much would this affect a 30 000lbs heavy displacement boat like the full keel Hans Christian?

It would affect it noticeably.

I feel like if there were to be a rigging failure it would come from a connections failure and not the cable itself but would it be wise to change to bigger cables or is 8mm plenty strong enough for circum navigation?

It is rare for standing rigging to fail because it wasn't strong enough. Standing rigging fails because of corrosion and fatigue.

It is rarely if ever wise to change to bigger cables, because standing rigging is designed as a system and the larger cables will increase the loads on chainplates, tangs, spreaders, and the mast itself, possibly leading to a system that is more prone to failure overall. Talk to a rigger or naval architect, or the manufacturer of your boat, for advice specific to your situation.

[psk125]

What Jammer said.

[AiniA]

I may take a different tack with this. We had a Bristol 45.5 with a very large single-spreader rig. We had two aft lower shrouds go - wires breaking, one in Indonesia (did you know you can't buy yacht wire in Indonesia), it either comes from Oz or Singapore. We reinforced the suspect wire and went to Christmas Island where a new piece of wire from Perth was waiting. We had Hayn Hi-mod fittings so it was an easy switch. The other was just approaching Richards Bay, South Africa. The rigger there said that for boats doing a circumnavigation almost always off the wind, the aft lowers take a tremendous load and need to be at least the same size as the cap shrouds. We upgraded just the aft lowers and it worked fine. We were able to use the same turnbuckles with the bigger wire.

I am sure Ted Hood and his minions specced the rig for the expected use of the boat, but possibly not for an unexpected use.

[Bowdrie]

Originally Posted by Mateolessa

How will this affect the vertical center of gravity?

I know that more weight higher (bigger cables) is supposed to affect the motion, vertical center of gravity and therefore affect the righting in case of capsize but how much would this affect a 30 000lbs heavy displacement boat like the full keel Hans Christian?

The designer probably knew what he was doing when he chose the wire size.
A survey I read years ago said that the most common cause of rig failure on a boat with a bowsprit was bobstay failure, it's the most heavily loaded wire in the rig and the lower end being basically immersed continuously is the weak point.
I would never contemplate a swedge/compression fitting at the lower end of a bobstay.
On boats without bowsprits, it was spreader failure that brought down the most rigs.
Center of gravity? change of capsize recovery?
Most of the weight of the bigger wire is below the spreaders, in the lowers and the lower portion of the uppers.
The change in stability over 25>35lbs of rigging in and of itself is inconsequential on a 30+K boat.
You'll change the righting moment more than the wire would by just sticking a radar at the spreaders, (it'll add weight and windage).
If it worried you, put an extra anchor in the bilge.

[s/v Jedi]

Reading the other comments, I do realize compromises are made and even when within the safety margins, there can be weak points. I know my mizzen forestays are lighter relative to the rest.

I think the size of the capshrouds should be good as designed but when the aft lowers would be a smaller diameter wire, this would worry me as well and weight is less of an issue for lowers.

We have upgraded our halyards to Dyneema so that they can be used for supporting the mast when there’s trouble with the rig, which is another way to make improvements for offshore sailing.

[Sowilo]

Dont change anything in a rigg-design before consulting a specialist.
It was designed as a complete coherent system.
I am almost 100% sure the answer you get is "Yes you can go up in size - but why do you want to do it". But do not trust me on this.

NB: Anyone can call themselves rigger. No certification. So be critical and choose one on reputation and experience.

[The Yacht Rigger]

Originally Posted by AiniA

I may take a different tack with this. We had a Bristol 45.5 with a very large single-spreader rig. We had two aft lower shrouds go - wires breaking, one in Indonesia (did you know you can't buy yacht wire in Indonesia), it either comes from Oz or Singapore. We reinforced the suspect wire and went to Christmas Island where a new piece of wire from Perth was waiting. We had Hayn Hi-mod fittings so it was an easy switch. The other was just approaching Richards Bay, South Africa. The rigger there said that for boats doing a circumnavigation almost always off the wind, the aft lowers take a tremendous load and need to be at least the same size as the cap shrouds. We upgraded just the aft lowers and it worked fine. We were able to use the same turnbuckles with the bigger wire.

I am sure Ted Hood and his minions specced the rig for the expected use of the boat, but possibly not for an unexpected use.

I'm curious, how old were the wires that failed?

[Benz]

I'd rather have new 8mm wires than ten-year-old 10mm ones.
I vote to keep the design specs as-is. HC 38s have done some big ocean sailing.
And the poster who pointed out the greater stress of bigger wire is right: 15% or whatever of pre-tension is going to be a lot more with bigger wire. You could back off your pre-tension numbers to match the strain on chainplates and mast tangs, but then you're re-engineering everything.

[s/v Jedi]

Originally Posted by Benz

I'd rather have new 8mm wires than ten-year-old 10mm ones.
I vote to keep the design specs as-is. HC 38s have done some big ocean sailing.
And the poster who pointed out the greater stress of bigger wire is right: 15% or whatever of pre-tension is going to be a lot more with bigger wire. You could back off your pre-tension numbers to match the strain on chainplates and mast tangs, but then you're re-engineering everything.

Exactly, rig tuning becomes impossible when using different pretension numbers everywhere.

But I do often see aft lowers being the same size as the cap-shrouds. I wonder how much smaller they were.

[Wandering1]

Originally Posted by AiniA

I may take a different tack with this. We had a Bristol 45.5 with a very large single-spreader rig. We had two aft lower shrouds go - wires breaking, one in Indonesia (did you know you can't buy yacht wire in Indonesia), it either comes from Oz or Singapore. We reinforced the suspect wire and went to Christmas Island where a new piece of wire from Perth was waiting. We had Hayn Hi-mod fittings so it was an easy switch. The other was just approaching Richards Bay, South Africa. The rigger there said that for boats doing a circumnavigation almost always off the wind, the aft lowers take a tremendous load and need to be at least the same size as the cap shrouds. We upgraded just the aft lowers and it worked fine. We were able to use the same turnbuckles with the bigger wire.

I am sure Ted Hood and his minions specced the rig for the expected use of the boat, but possibly not for an unexpected use.

Which part of the aft lower failed? Was it where the wire went into a hydraulic swaged fitting?
Hydraulic swaged fittings are often the source of failure of a wire. Wire failure in the middle of a length of wire is almost unheard of unless the wire has had some mechanical damage.
In addition, if the rig is not tensioned correctly, thr mast can pump. The wires that always fail are the shorter wires such as baby stays and aft lowers. They don't have sufficient stretch to deal with the mast movement compared to the longer wires such as caps and backstays.
Converting to Stalok mechanical swages and dieform on any wires that need additional strength is always a good upgrade especially for going offshore and covering lots of ocean miles

[Icarus]

10mm caps, 10mm after lowers, 10mm forestay, 8mm after and fwd lowest...is more than enough