shroud tensioning

[patsheridan]

popped one of the shrouds yesterday coming off the spreader on my islander 24, and now that i have to reconnect it i am wondering how much tension the shrouds should have. all the other shrouds have a bit of play in them, and i don't know if this is from the passage of time or whether they should have just a bit of play.

thanks in advance.

 

[jimcreed]

shroud tension.

popped one of the shrouds yesterday coming off the spreader on my islander 24, and now that i have to reconnect it i am wondering how much tension the shrouds should have. all the other shrouds have a bit of play in them, and i don't know if this is from the passage of time or whether they should have just a bit of play.

thanks in advance.

Tension is usually based upon wire size. All shrouds should have some tension.
There are gauges to test this. Check West Marine catalog.
Gauge usually list appropriate tension for specific wire sizes.

 

[Ray T]

Jimcreed is correct but I would like to add that shrouds should be attached to the spreaders either with wire or some other means. A shroud should not pop off the spreader if loose.

 

[Ted]

The tension applied to your shrouds during mast tuning are a percentage of the breaking strength of the specific wire diameter and will vary by boat and rig type. For instance, on my boat, I have single lowers and uppers. I tension my uppers at 19% and lowers at 14% of breaking strength. Go sailing in moderate winds and sight up the mast at the main sail luff. If the mast is falling off in the middle, snug up the lowers slightly to bring the mast into column again. Always check tension to make sure you are not exceeding about 20% when not sailing. The max percentage depends on your boat. Some boats bend more than others. So dramatic is the boat flex that the more tension that is applied to the shrouds, the more you will bend the boat, and you will never be able to apply 20% without breaking something. A general starting point is about 10-12% for lowers and 15-18% for uppers for a masthead rig with single or double lowers and single spreaders.

 

[sand sailor]

thats way too loose

 

[patsheridan]

ray t - i mis-spoke. i was trying to say only that it is the shroud that comes thru the spreader. the actual detachment occured down at the deck.

sand sailor - what are you referring to?

 

[bffatcat]

I been tuning rigging for the last 50 years or so by hand and feel. without any guages or instruments The instructions below are for a mast head rig and for cruising. Ive never had a failure or problems. For Racing a differnt set of parameters apply depending on the boat.
You said you had and Islander bahama. Thats an old boat You didnt say how old the rigging was. If its over 30 years old it should be replaced. For the sake of this post lets assume its still servicable. For every day cruising things should not be loose or flopping around on either tack. 1. Start with the mast plum. This means no rake fore or aft. Site up the track if there is curve ease the upper on the side of the curve until the mast is straight. 2 The uppers should be tighter than the lowers. Not like a banjo string but tight enough so the lee upper is not flopping around when sailing to weather. the lowers should also be tight but not as tight as the uppers. You dont want that mast bendig orr moving around. Oh and make sure your uppers are securley wired into the spreaders. Its a good idea to put boots on the spreaders instead of just tape
Bear in mind this is just a starter tune. It should keep you free of trouble. A fine tune takes more expertise and experience

 

[Stu Jackson]

I'm with bffatcat on this one

Most association websites have manuals, and Catalina's shroud setup explanation is very good. While most of the Catalinas are masthead rigged, and I think the IB24 may be a 7/8 rig, the concept is pretty much the same.

You can read the Catalina rigging suggestions here: http://www.c34.org/manuals/1988/1988-C34-Owners.pdf

Go to page 19 and 20 of 66 on the pdf file

 

[sand sailor]

if the stays are popping off the spreader thats way too loose but if they pull off the deck thats a whole nother problem

 

[sand sailor]

did the fitting pull off or the cable break

 

[higgs]

Pat

I am guessing that since you don't mention about anything breaking, that either your turnbuckle loosened and fell out of the barrel, or your clevis pin came out. Either way you must use either cotter pins or slip rings to ensure all your rigging won't just come loose. There are holes in both the clevis and the threaded studs for this purpose. Sometimes backing nuts are used on the turnbuckles.