Sizing standing rigging

[Ubergeekian]

I am nearing the end of a restoration of a Hunter 490. Earlier this week it went back on its keel for the first time in 20 years and I had a go at raising the mast, using the nic enew rigging I had made as an exact copy of the old stuff.

Disaster! The backstay was a foot and a half too long, the shrouds (outer and inner) and babystay were four inches too short and even with the mast properly upright the forestay would probably have been too short by an inch or two.

Either the rigging I had copied was the wrong stuff, or it was copied badly, or the previous owner used a bizarre number of toggles - and managed to tie a sheepshank in the backstay.

So, what do I do now? I see two options. Either

a. Raise the mast with strings on most things and a temporary short backstay, measure the differences and have the lot remade or

b. Measure the geometries of the hull and mast attachment points and calculate lengths from scratch. Thank you Mr Pythagoras.

What would you do? I reckon the calculation method would be a lot quicker, but I am tempted to measure real stuff instead of doing sums.

 

[rjp]

You can get extra long swageless fittings which would probably give you an extra 4 inches or even more - I have a couple in my rig and they don't really look out of place. Also toggles at each end might help if you don't already have them - good practice anyway. Obviously shortening should not be too much of a problem.

John

 

[Ubergeekian]

You can get extra long swageless fittings which would probably give you an extra 4 inches or even more - I have a couple in my rig and they don't really look out of place. Also toggles at each end might help if you don't already have them - good practice anyway. Obviously shortening should not be too much of a problem.

Thanks for that. I'll investigate these fittings - can you recommend a supplier? I though about lots of toggles, but they're blinking expensive! I'm using nice new Jack Holt rigging screws which have toggles built in to the bottom - as you say, it's good practice. Same overall length as the old ones, by the way...

 

[dmmbruce]

Don't try pythagoras unless you are a lot better at it than I was!

Stick to the practical approach.

Good luck
Mike

 

[alahol2]

Option c) could be to take an inch or so off the base of the mast?

I'll get me coat...

 

[Refueler]

Before you go spending money ...

A few minutes spent with calculator, tape and pencil may help.

Measure mast, stem to mast base, height mast base above horizontal deck line from stem, mast base to mid transom for backstays, offset from centre transom to actual backstay fixing, mast side stay fixings to base, height mast base above horizontal from side stay fixings, distance side stay fixings to mast base.

With these and a calculator ...... pencil and graph paper ... you can now construct rigging diagrams that give you reasonable stay lengths.

It may sound silly ... but have you fitted the stays in right positions ? Second a too long stay is not a real problem ... can always be cut back to fit, but a too short is a disaster unless you have somewhere else you can use it by shortening ...

Considering cost of rigging ... it's worth the effort to measure etc.

 

[Ubergeekian]

Before you go spending money ...

A few minutes spent with calculator, tape and pencil may help.

Measure mast, stem to mast base, height mast base above horizontal deck line from stem, mast base to mid transom for backstays, offset from centre transom to actual backstay fixing, mast side stay fixings to base, height mast base above horizontal from side stay fixings, distance side stay fixings to mast base.

With these and a calculator ...... pencil and graph paper ... you can now construct rigging diagrams that give you reasonable stay lengths.

That's basically my measurement option, though I am putting together a spreadsheet to do the sums!

It may sound silly ... but have you fitted the stays in right positions ?

Good question. I am pretty sure that we did. The babystay and inners are a LOT smaller than the other four, so they are easy to get right. Of the four long ones two are identical lengths, so must be the outers, and the others are an inch or two different: we had the longer as the forestay, which is too short, and the shorter as the backstay, which is too long, so swapping wouldn't have helped.

Second a too long stay is not a real problem ... can always be cut back to fit, but a too short is a disaster unless you have somewhere else you can use it by shortening ...

Considering cost of rigging ... it's worth the effort to measure etc.

The backstay can be cut down fine, and the forestay and outers will make new babystay and inners, so the worst I will need are four new talurit eyes at a fiver a go and three wholly new stays ... luckily not too expensive: this is a titchy boat (4.90m) and the stays are 3mm stainless. Think slightly beefed up Wayfarer.

Many thanks for the advice.

 

[rjp]

Thanks for that. I'll investigate these fittings - can you recommend a supplier? I though about lots of toggles, but they're blinking expensive! I'm using nice new Jack Holt rigging screws which have toggles built in to the bottom - as you say, it's good practice. Same overall length as the old ones, by the way...

Mine were Sta-Lok fittings I think, supplied by Bollin Rigging who are in Cheshire, but you should be able to get them through any rigging supplier I would think. If you look at http://www.steelwirerope.com/WireRo...rminals.html?gclid=CImS2LmXxpwCFWIB4wodF1HbLA you can see the kind of thing I mean - last but one to the right of the picture (no knowledge of this supplier, just googled Sta-lok and found it).

John