standing rigging..??

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captfolly
Posts: 24
Joined: Fri Sep 19, 2008 12:00 am
Location: Stuart, Florida USA
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standing rigging..??

Post by captfolly »

Hi everyone on the forum...we are going to replace the rigging wire on our 1984 snowgoose 37...we have a 39' double spreader isomat spar and all wire is 6 mm with 1/2" turnbuckles...the rigger (riggingonly.com) suggested that the wire size seemed a bit undersize...is there a rigging spec somewhere?...I am thinking the original rig survived for 26 years so should be good enough, maybe increase size to 9/32" without changing any terminal fittings on the mast...we are presently cruising about florida but will head north towards the chesapeake in a couple of weeks...thanks all..!

fair winds,

George & Doris
svgeru
Posts: 26
Joined: Sun Nov 02, 2008 12:13 am
Location: Ottawa, ON, Canada
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Re: standing rigging..??

Post by svgeru »

George & Doris,

Glad to see the dream is still alive.

I know when our mast was replaced they up-sized the rigging (as we have one shroud smaller than the others!). Send me an e-mail if you would like me to check what ours are.

Geoff
SV Geru.
svgeru
Posts: 26
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Location: Ottawa, ON, Canada
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Re: standing rigging..??

Post by svgeru »

I'll reply here so all have the information:

Our Snowgoose 37 has all but one of the stays slightly larger than 9/32" and one slightly smaller than 9/32"

Geoff.
sv snowqueen
Posts: 5
Joined: Sat May 22, 2010 11:57 pm
Location: Clyde Estuary, Scotland

Re: standing rigging..??

Post by sv snowqueen »

i have a Prout rigging drawing from 1979 for the Snowgoose 37 with the single spreader 37ft mast. This specifies 6mmx1x19 stainless steel on all stays and shrouds except for the forestay which is 8mm. Unfortunately, it does not specify the design tension for the various stays or the mast rake, if any.

I also have a specification/price list from 1985 for the single spreader 37ft mast which again indicates 6mm except for the forestay which is 9mm.

My own 1979/80 Snowgoose 37 has a single spreader 37ft mast with 8mmx1x19 stainless steel on all stays and shrouds.

The key is to find out the design tension for the original 6mm wire and hence the loading on the shroud plates and mast support as specified by the designer. Normally (for monohulls) this is 15% of the breaking strain of the design rigging diameter.

I tension the 8mm wire to just under 10% of its breaking strain which is equivalent to about 15% of the breaking strain of 6mm. (If I tension the 8mm cap shrouds and lowers to 15% of the breaking strain for 8mm, the aft cabin doors become a tight fit.)

Ed
Lotusmantra
Posts: 20
Joined: Sun Dec 08, 2013 12:41 pm

Re: standing rigging..??

Post by Lotusmantra »

I changed my standing rigging last year on my 96 Elite which was 16 years old. I had never seen any defects and done it only as I'd heard insurance companies desire one to change every 10 years. It has the double diamond rig and a bit different to yours but general tensioning would be similar. I have a manual (now scanned to a PDF file) that am willing to share for the Prout 34/37/39 which gives some information about rigs. It doesn't give exact tension but states that wires shouldn't be over-tight. Although not mentioned to do so in that manual, I took some measurements in various places with makeshift feeler gauges before I started tensioning. One measurement that showed up clearly as to the maximum tension allowed was the space above the cockpit door. I stopped before I altered the cabin top shape and have made many miles since.
Decibelle
Posts: 2
Joined: Tue Aug 04, 2015 4:02 pm

Re: standing rigging..??

Post by Decibelle »

Greetings,
This is my first post to the Prout Owners forum. I have a 1995 37 Snowgoose Elite that is nearing the end of a refit. Lotusmantra, is the manual you refer to the Owners Manual? I have a copy of the Owners Manual but it's marked as a "Draft" version, and of course there's no date on it. (Why don't the Brits ever put dates on their manuals and brochures? No offense intended - my husband is a Brit!) So if you have a different manual, or one that actually has a date on it, I would be grateful if you could share it. Many thanks.
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