Backstay tension, calling all H37C riggers!!!

[Richard McDonald]

Just finished servicing the old Hyde Streamstay furler and was wondering what the correct backstay tension should be.The Hyde furler rod is a size #9, which represents 9/32" wire size with a breaking strength of 10,500 lbs. The backstay on my H37C is 9/32" with also a breaking strength of 10,500 lbs.According to some rigging reading I have done, they suggest a tension setting of 15% of breaking strength on the masthead rig which represents a set tension of 1,575 lbs measured on the backstay. When I set this tension on the backstay, the mast has a slight rake back at the top. Should a masthead rig be straight with no back rake? Should I shorten the furler rod length (I still have some adjustment available on the bow T-bolt) to remove the mast back rake when under tension?Does this make sense?Do other H37C owners have a different setting?RichardS/V Rhapsodie 1979H37C

 

[Ed Schenck]

No rake here.

Maybe you could pose the question over on the Guest Expert Forum, "Sail Trim". I once viewed the Brion Toss video where he tensions a cutter. I don't think there was any rake.Mine looks straight to my eye. I loosen the mid-stay and shrouds before I start. I tension the backstay and check. The first time there was some rake. Loosened the backstay and took several turns up front. Then retensioned. Not sure if it is right because I have some weatherhelm when sailing without the staysail. Maybe we will get a definitive answer here.

 

[Richard McDonald]

Ed, what....

Ed, I suspect that the mast should not have any rake when correctly tensionned. What tension did you set on your backstay?I hope we get more answers from H37C owners, confirming or not if there mast is straight (no rake baskwards) and what tension levels they have set on their backstays.Richard

 

[Dave Stone]

Major difference

between bend & rake. If you are seeing "rake" above the stay but not below, you are talking about mastbend. Rake is what you get with a perfectly straight mast that is not truly vertical in the fore & aft plane. I sail San Francisco Bay & all the 37c's that I've seen have varying degrees of rake. Mine is raked so far aft that the backstay rubs on the stern pulpit. I don't know what the correct rake is.I would think that the mast should be straight. No bend at all because the section is pretty deep fore & aft. I was taught that the upper shroud should run in a straight line from the chainplate through the center of the spreader base to the center of the masthead. I have not been able to achieve this. On my boat it would require the mast to rake forward. So, over to Sail Trim?

 

[Ed Schenck]

That's right Dave.

Maybe some rake but never any bend. As you point out I don't think that mast should be bent. When last I stepped the mast I had to use the shrouds and backstay to move the mast side to side, front to back. It was the only way I could get that hard rubber seal down inside the partners. But with the boat in the water I hang a weight from a messenger line on the halyard. It hangs right against the mast(or used to). Everything is loose as she sits on the cradle for the year.As an aside, a question I posed once before. Does anyone worry that our Hyde solid-rod furlers are old?! True, we have the mid-stay which offers some support. But not having a forestay that can be replaced bothers me a little.

 

[Richard McDonald]

Dave, mast bend it is...

Thanks Dave for the clarification. I am talking of mast bend above the staysail stay to the top of the mast, which would mean that I need to shorten the forestay furler length to straighten the mast.I do have some mast rake aft, as you do and my backstay turnbuckle does also rub against the stern pulpit.How about tension setting, is 15% of breaking strength right for the backstay?Ed, you do have a point concerning our 1979 furler solid rods. As anyone ever broken one?

 

[Seattle Scott]

I bend

with adjustable back stay when the wind picks up. Both to depower the main and tension the jib luff. I maybe shorten back stay two inches at most. I adjust the inner forestay so the bend starts below the top of this stay. If the inner stay is too tight, all the bend is above the stay and looks pretty severe and potentially damaging given the short distace between top of stay and masthead. I think mast has no rake. I keep forward lowers tighter than aft lowers. I have never put a gauge on anything though.