Measuring new standing rigging from scratch?

[steve yates]

How would one go about deciding what lengths of standing rigging to order, if there was no existing rigging, just the spars on a trestle and a collection of bottlescrews?
Its a very small boat, 18ft so no stalock terminals etc in consideration, as its probably cheaper to take the mast back off and reorder new rigging if I got the order wrong than buy compression terminals.

On a similar vein, if just a bit too short, is just adding an extra toggle or two a viable idea?

Lastly, the deck ends were previously terminated with a stud to thread into a bottle screw, taking into account the above, would it be better to terminate it in a toggle, which could be attached to different sized bottle screws rather than a single size?
Thanks

 

[srm]

Extra toggles, no problem. I did this when fitting a new 8mm forestay and roller reefing gear on 35ft cutter rig. Standard length I ordered was just a bit too short (and next option was 1.5 metres too long) so added two toggles at bottom. Has lasted 15 years and quite a few thousand miles including some ocean sailing in 40kn plus conditions.

 

[scozzy]

Jimmy greene marine is who you need to speak too, I found them v helpful over phone dealing with my rigging, no affiliation just happy customer

 

[dunedin]

For such a small mast could you put it up with temporary ropes as rigging, and then adjust these to determine sizes?

 

[Refueler]

My 25ft Motor sailer - previous owner made error in length and one stay has two toggles ... been fine for the 25 odd yrs I've had the boat ...

As regards lengths ..... dunedin has it in one :

Get rope and rig it .....

Once rigged - then take a halyard and use that with a long tape measure to gauge the lengths required .... as long as you are within the range of bottle screws adjustment with your measurements - all should be fine.

 

[Poignard]

Pythagoras is your friend

The Pythagorean theorem states that in any right triangle, the square of the length of the hypotenuse equals the sum of the squares of the other two sides.

 

[Refueler]

Pythagoras is your friend

The Pythagorean theorem states that in any right triangle, the square of the length of the hypotenuse equals the sum of the squares of the other two sides.

Fine - except that very few boats have right angle triangle rig ... the mast foot usually higher than the chainplates .... mast rake from vertical alters the fore and aft stays ...
If you have spreaders ?

 

[Poignard]

Fine - except that very few boats have right angle triangle rig ... the mast foot usually higher than the chainplates .... mast rake from vertical alters the fore and aft stays ...
If you have spreaders ?

This chap explains how it's done:

 

[Refueler]

True ... clever chap !!

But note that its not actually Pythagoras and Right Angled triangles .. its using what I said in this more recent post ... rig the mast and use halyard and long tape measure ... all transferred to graph paper (calculator used to factor the scale and additions). Of course for partials - Pythagoras comes in handy ...

Yeh ... fancy that ... bloody clever chap !!

 

[ridgy]

Gs products very cheap for that size of wire, can order custom shrouds from website. Guessing 3 or 4mm. Extra toggles might work structurally but aesthically the work of an amateur. Swaged screws going straight to bottle screws the neatest but in this case go for fork each end and use temporary rope to determine length

 

[Rhylsailer99]

Fine - except that very few boats have right angle triangle rig ... the mast foot usually higher than the chainplates .... mast rake from vertical alters the fore and aft stays ...
If you have spreaders ?

cosine rule it is then.

 

[Poignard]

cosine rule it is then.

Or the sine rule.

 

[RunAgroundHard]

You guys do go off on a tangent at times.

 

[Poignard]

You guys do go off on a tangent at times.

You've struck a chord there.

 

[Refueler]

Haversines anyone ?

 

[Poignard]

Haversines anyone ?

No, but if you're paying I'll haverpintofbitter.

 

[B27]

Borrow some old rigging.
Cobble it together with wire rope grips to get the lengths right.
Copy lengths to new rigging.
Or you could make adjustments using dyneema lashings then you'd know how much to extend the dummy rigging by.

With talurit type crimp ferrule hard eyes you can put a new eye on, shortening the wire by a few inches, so you could rig the boat temporarily with shackles and dinghy-style adjuster plates, then shorten to suit your bottle screws.

If you're going to do it by measure and calculate, the hard part is measuring the height of the chainplates and forestay tang or whatever relative to the mast step. It might be worth putting together a frame to use as a reference.

 

[john_morris_uk]

Last time I had to do this, the riggers cut the rigging wires too long but swaged on the upper fittings. I fitted the rigging to the mast and then when the mast was stepped thd riggers came along with a portable swaging machine and cut the shrouds etc to length and fitted the turnbuckles. Mast was held up temporarily by halyards etc while they cut and swaged.

 

[steve yates]

Gs products very cheap for that size of wire, can order custom shrouds from website. Guessing 3 or 4mm. Extra toggles might work structurally but aesthically the work of an amateur. Swaged screws going straight to bottle screws the neatest but in this case go for fork each end and use temporary rope to determine length

Thats exactly who I’m using, £22 per stay
Hence why I said its cheaper to redo than get stalok type rigging terminals.

 

[steve yates]

True ... clever chap !!

But note that its not actually Pythagoras and Right Angled triangles .. its using what I said in this more recent post ... rig the mast and use halyard and long tape measure ... all transferred to graph paper (calculator used to factor the scale and additions). Of course for partials - Pythagoras comes in handy ...

Yeh ... fancy that ... bloody clever chap !!

Thats quite usedul as I did that, using battens out from the mastfoot to intersect at 90 degrees above the chainplate. that gets me the main triangle, to calculate the stay length to thatpoint then add the legth from the intersection down to the chainplate.
I wasn’t sure if I was on the right track with that but it sounds like it.

Thanks all