Oversized rigging

[webcraft]

Any reason not to go up 1mm when replacing the standing rigging?

(5mm - 6mm, 27ft Albin Vega)

- Nick

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[Strathglass]

If the boat was originally designed for 5mm then there are no real advantages in increasing to 6mm unless you also replace the bottle screws, chain plates and mast fittings. They will all have to be sized up accordingly and the chain plates,bow and stern fittings properly designed.

You will also have

More weight aloft,
More windage,
Will cost more,
Will not last any longer

You will get less stretch but the weekest link is the fittings at the ends, you will get no more reliability by increasing the wire size.
Look at the weight difference between 5 & 6mm wire then think about that hanging on your mast, giving you no real advantage. You will have something like 70 metres of wire in your rig.

All in my opinion of course,

Iain

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[webcraft]

Hi Iain,

Thanks for replying. Upping the rigging a size is often mentioned in books as a good thing to do if equipping a boat for bluewater, but I was interested to see if anyone had any practical experience or views.

Going from 1x19 5mm to 6mm the breaking strain increases from 2000Kg to 2,880 Kg, while the increase in weight is 46%

I lifted the rigging out of the boot of the car today and reckon it weighs maybe 10Kg max, so extra weight in total is around 4Kg, corresponding to maybe 1.5Kg at the masthead at the most - certainly very much less than a radar or in-mast furling, for example. I doubt if it would make more than a degree difference to the AVS, which will be more than compensated for by putting an extra water tank in the keel void or stashing cans in the bilges.

The professional rigger I spoke to reckoned 5mm was in the lighter half of the range for a boat that size - i.e. 5mm or 6mm would be expected, more likely 6m. He seemed to think that the overall life of the rigging would be likely to be extended, and that case hardening through working of the rigging would be greatly reduced.

Intention is to renew all the bottlescrews at the same time with the appropriate size. The mast fittings look good and more robust than other terminals; after all, they are not designed to be replaced, so I am not too worried about them.


My main concern would be overtightening the rigging and putting too much strain on the deck or chainplates . . . if the view that rigging shold be tightened to a %age of its breaking strain is correct then this would suggest that heavier gauge rigging must of necessity be tighter. The only rigging failure I have heard of on a Vega was when the bow chainplate went, so your comment re. chainplates is certainly valid.

I've also heard it suggested that windage is increased, but as the new rigging wil be shinier and slippier I can't see this as being significant. Overall I'm definitely inclined to go for it, but more opinions and thoughts would be welcome.

(Plus I'm still waiting for a price - the wire is probably only going to be 20% more, but the bottlescrews and eyes may well be much more - so this could also be a deciding factor).

- Nick






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[johnsomerhausen]

Nick, hen I bought my boat second-hand in 95, she was equipped with 5.5 mm (7/32") rigging and I assummed that to cut costs, the builder had chosen the minimum acceptable size and went to 6.35 mm (1/4") to make it solid enough for a transtlantic crossing. I changed the aluminium chainplates for SS ones as a friend had told me that nobody knew how aluminium fares after 18 years in a marine environment. Changed the turnbuckles also but kept the mast tangs as they seemed to be the right size. As far as the tension goes (should be 15% of breaking strength), I'm of the old schools that considers that close-hauled in a Force 4, the lee rigging should feel slack but not "look slack", so I don't really know whether my tension is right but that 29 footer has crossed the Atlantic to Europe and back via the Caribbean and gone through four Force 8's and one Force 9 so I suppose I have things more or less right
john

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[Strathglass]

Hi Nick
I think your reasons for wanting to increase thr rigging sizes are quite valid.

I would not be too woried about over tensioning because of the thicker rigging. As has been stated I alse prefer to have the lee shroud feeling just slack when beating in a force four.

Your hull is of quite solid construction so I don't think you will be able to turn it into a 'banana boat' with over rig tension.

I have just finished making the mast for my new yacht and have opted for 8mm 1/19 wire instead of 7mm but all the other fittings are sized to match. I have rig tension gauges but ultimately tensions will be set dynamically on the water.
The gauge will be used to set initial tension then it will be used to check for stretch with time.

The cost of 10 stays with T ball sweged fittings at one end and open at the lower end in 8mm wire cost £410 (twin spreader with babystay and removable forestay). This is for about 100 metres of wire.
I have not yet purchased the ten swegeless turnbuckles with swivles but they will cost between £500 and £600. I intend to use Petersen ones as they are much easier to use than some other makes.

I will be quite interested in reading what other formites opinion on your query will be.

Iain

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[Roberto]

Nick,

just to add my 2p to the interesting pro and cons already posted, if your boat rigging is designed properly, you probably have a safety factor of 5ish for the chainplates, 3 for the wire and 4 for the turnbuckles (they may be rounded off of course, due to non existance of 5.35mm wire or 6.13mm plate)
Going up from 5 to 6mm would bring the safety factor for wire from 3 to 4.2, too near to the s.f. of turnbuckles (unless you step up one size there) but still under that of chainplates, which of course you want to have the highest safety factor.

if you know the existing setting breaking strengths you can figure out the (at least relative) safety factors you have, and see if increasing the wire size keeps the same hyerarchy of safety factors among wire, turnbuckles, chainplates, tangs, etc.

all imho of course

rob

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[charles_reed]

Here are 4

1. Rigging is designed to fail before hull - going up may prejudice this common-sense fail-safe.
2. Greater weight aloft raising the C of G
3. Greater cost for a dubious benefit
4. Will it fit the present fitting points?

I know a charming swiss medécin who complained that his Lac Leman boat was leaking due to the waterline being above the stern tube. Being an ex Croix Rouge he, as you are proposing, equipped his boat with REALLY STRONG rigging, ground tackle etc.
I haven't yet had the heart to tell him it's self inflicted.

In the words of Colin Chapman - "Simplificate and add lightness"

PS Well he was an engineer and no grammarian.

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[snowleopard]

think back, if you are old enough, to the comet and 707. the comet was strong enough to do the job but only by a small margin. as a result it was very prone to fatigue. boeing solved the problem by making the structure of the 707 massive. they didn't eliminate fatigue but the heavier structure was able to cope without breaking.

so heavier rigging is bound to reduce the risk of fatigue failures. of course they can still happen in the fittings at either end so you might consider increasing the sizes of bottlescrews, toggles, clevises etc.

of course your insurance company will be unimpressed and still expect you to replace at the same intervals.

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[Robin]

How long has the existing rigging lasted? Why are you looking for more strength, is it 'just in case' or for some planned voyage? I don't think Vegas are known for dropping masts overboard so without a specific reason would stick to standard, rather than have extra weight aloft and extra expense. Another option would be to use Dyform (spelling???) wire which has shaped strands snuggly fitted together, more strength for the same diameter, but again more expensive.

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[MIKE_MCKIE]

Slight disagreement re the Comet. My dad was Squadron Engineer on the Comets in RAF and worked on them when they were trying to find out why they fell out of the sky. The end result was fatigue, but it was caused by incorrect SHAPE of the windows, not by incorrect scantlings. They made the windows with rounded corners & had no further problems. He flew them from start to finish of their RAF service & there was not one single failure, or even a hint of a problem. Most aircraft were eventually sold to charter airlines (DanAir for one), and many of the pilots were ex RAF as well. In fact when my new wife & I went to Portugal on honeymoon with DanDare in 1972, the aircraft & almost entire flight staff were all ex-neighbours from Lyneham!
Fully agree that Boeing beefed up the 707 & even more with the 747, that thing is like a tank.
As to beefing up the rigging, my 26' sloop has 5mm lowers & 6mm masthead stays, & I consider that plenty. The Vega is a well designed boat that has been around for years, with some impressive passages to it's credit. Cannot see the point in over engineering things just for the sake of it.
Mike

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[webcraft]

Thanks everyone,

Much to ponder, with good arguments both ways. Price may yet be the deciding factor.

Main reason for thinking of doing this is because I hope/intend to add to the list of impressive passages made by Vegas, and intend to make the boat as 'bombproof' as possible first.

- Nick

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[halcyon]

Our boats previous owners increased to 7 mm when they reached the States. One of a number of mods to the Halcyon 27 after the Atlantic crossing. Still have to decide what we do when we come to replacement, then there is the question, what do two Atlantic crossing equal in normal cruising rigging wear?, thus how soon do we replace.


Brian

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[johnsomerhausen]

Brian, it seems theree is a saying amongst insurance companies "One circumnavigation, two transatlantics or 10 years normal cruising". Since the ten years seem to be coming soon and your mast is still up, you could take that as the marker
john

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[Mudhook]

Simplicate older than that!

The phrase "simplicate and add lightness" goes further back than Colin Chapman. It has been attributed to various aircraft designers, notably Ed Heinemann who designed several simple and light jet fighters in the 1950s at Douglas, and before to that William Bushnell Stout who designed the legendary all-metal Ford Tri-Motor in 1925. They'll still be using it in 2104 I'm sure!

Regards, Mudhook.

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[kds]

Re: Simplicate older than that!

Lightness ?
Didn't Uffa Fox say that the only place for weight was on a steamroller ?
The Vega reputation speaks for itself and so it looks like the designer got it right.
Are you sure your design would improve it ?
If it aint broke; don't fix it !
Ken
I am thinking of rducing my backstay from 6 to 5 mm. as backstays at at so much less of an acute angle to the mast that the strain must be far less than, for example, the forestay ?
Comments ?

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