Backstay Tensioner

[Sam Salter]

Not sure if this is the right place for this, but I think I'm going to get a more experienced opinion here!

26 ft C&C. Masthead rig; mast like a telegraph pole!
I'm about to change all the standing rigging - not sure how old it is, so I'm being prudent. While I'm at it, It would be easy to add a backstay tensioner - I'm thinking Wichard or similar.
My thoughts are:
Probably won't bend the mast much, if at all, but would improve pointing to windward by tensioning the forestay and flatten the genoa when needed.

Is it worth doing?
Am I going to see, feel a difference? Or am I just looking for ways to spend money on the boat?

sam

 

[Joe]

On a masthead rig the function of the backstay tensioner is to control forestay tension. So.....yeah I think it's worth it... although on a 26 foot boat you don't have to spend a lot of money on hydraulic systems and such. A simple 6::1 or cascaded 12::1 as shown in this link http://www.harken.com/rigtips/BackstayAdjuster.php would be more than adequate.

 

[Don Guillette]

Sam: I truely hate this subject so I'll just jump in get out as quickly as I can. As you've noticed you don't have a "bendable' mast. When you crank on the backstay adjuster all you're doing is RAKING the mast backwards and adjusting the forestay as pointed out by Joe from San Diego. What happens is the boat thinks you picked the mast up and moved it backwards and the result is you induce weather helm. A little mast rake (less than 6") is OK but a lot of mast rake is not.

The true purpose of the backstay adjuster on a bendable mast setup, like a J Boat, is to take the fullness out of the middle of the mainsail thus flattening it. To see what is happening just bend and straighten your forefinger. When you bend your knuckle you'res pulling the fullness out of the sail and when you straighten your finger the fullness is put back. If you had a "bendy" mast you'd be adjusting DRAFT DEPTH and mast bend is also one of the controls used to adjust DRAFT POSITION.

So, raking the mast aft won't improve pointing but it will induce weather helm and if I wanted to flatten the jib I'd use the fairleads, halyard or jib cunnigham (which I prefer) and the jib sheets. If I had a bendy mast I'd use the backstay adjuster also. Cranking on your backstay adjuster and raking the mast aft, by itself, will not flatten the jib.

On my catalina 30 I had one of the most expensive backstay adjusters Garhauer made. I forget why they gave it too me - it was for something I did for them. I could never afford it. I never really used it. Sometimes I'd fool around with it. The main reason I kept it on the boat was it looked trick!!

I had a dock neighbor in Long Beach, Ca who would tell me that his backstay adjuster was his accelerator and he used it all the time. I would tell him "that's good to know" but we never had any serious sail trim controls use discussions.

The bottom line is that when a mate decideds to either add a sail trim control or to use one to adjust either their main and jib they must know what the devise is adjusting and the results that will be attained. Otherwise the results won't be what they think they will be.

 

[Sandy Stone]

I think a backstay tensioner is useful, even if you do have a telephone pole mast. At least on the boats I have sailed, when you're going upwind with the jibsheet cranked in, the sheet tension in combination with wind loading tends to drag the headstay back and to the side, significantly affecting sail shape and pointing ability. By adding backstay tension, you can in turn increase headstay tension, and partially counter that effect. This is at the cost of increasing strain on the rig, mast step, and indeed the structure of the boat. The nice thing about the adjustable backstay is that when you don't need the extra tension any more (i. e. downwind, or at the dock) you can ease it and give the boat a little bit of a break, as opposed to having a tight rig all the time.

 

[Stephen K]

Is it worth doing?
Am I going to see, feel a difference? Or am I just looking for ways to spend money on the boat?

sam [/quote]

Sam,
I contemplated the same question with my prior C-30 and still do on my current C-36. I should add that I don't race, but enjoy the aspect of sail trim and sailing as fast (and efficiently) as possible. I also enjoy spending money on improvements that make sense (at least to me)

If I were to prioritize sail trim "hardware" expenditures for a masthead rig, I would consider:
1st - adjustable genoa fairlead system
2nd - rigid boom vang
3rd - backstay adjuster

 

[Sam Salter]

I've got adjustable genoa cars and a ridged boom vang.
I've replaced the traveler with a new Harken.
sam

 

[steelcastle]

I am a novice and just learning, and studying quite a lot.

What I have learned about the backstay adjuster on my boat is that when the stays are loose, the forestay is slack which allows the foresail to bellow forward and catch more wind. When the backstay is tightened, the foresail flattens because the forestay is tight.
Thus, low wind, slack forestay. High wind, tight forestay. But as a novice, I am open to better ideas.

 

[Cayennita]

I had a Seidelman 30 with hydraulic back stay and adjustable baby stay. Even though it was a telephone pole, in heavy air the headstay will sag and the backstay will correct this. In turn it will help to flatten the main. The baby stay will pull the middle of the mast forward also helping to flatten the main and you still have the cunningham and vang to help out. The boat had a 42' I dimension.

 

[Barnacle Bill]

Steelcastle, what you describe is what happens when you tighten the luff of the sail or loosen it with the halyard. When you tighten the halyard, that brings the draft forward for more power. When you loosen it, it brings the draft aft, which flattens the leading edge of the sail, which helps with pointing because of the finer entry. Usually you want to tighten the backstay when the wind pipes up. When the wind lessens, you don't need so much tension. Also, there is the relationship between the forward lowers and the backstay. If anyone's boat has a forward lower, tightening the backstay will definitely put a bend in the mast even on a stiff mast seen on many masthead rigs. This is consistent with the bias of the mainsail. It does help the boat perform in heavier air and also helps tighten the forestay for better windward performance. A fractional rig, like a J/Boat has smaller headsails and a very large main, where a masthead rig uses much bigger headsails and smaller mains, generally. The major horsepower is shifted between the two designs from headsail to main/masthead to fracitional respectively.

 

[RobertLangdirect]

Don;

I have a 1978 Pearson P-31. This is a 7/8 fractional rig and yes, it has a backstay adjustment. I know and have experienced the flattened main, when I needed it in high winds and when I forgot about it and stalled out in very light winds.

So, what is the order for setting sails and adjusting stuff on the boat.

Jib then Main?

Jib -- sheet, car, cunningham (is that the extra line on the edge and bottom?)

Main, halyard, cunningham, downhaul, outhaul, backstay, in that order?

I know that every situation calls for adjustments, but as a general rule, what is a normal process?

Thank You!

Robert Lang

 

[Alan]

Some guys are lucky and have the luxury of a good working crew. In that case everyone knows his job and trims or eases as the situation arises. Most however, don't, so the order becomes a factor in maintaining speed and balance. In general a fractional rigged boat has its main as the 'main' power source. The main should be trimmed first. In a masthead rigged boat the genoa is the 'main' power source so it should be trimmed first. In most tacking situations the halyard, cunningham, outhaul and backstay will pretty much remain the same provided there are no real wind speed changes. If you had running backstays or check stays they of course would have to be eased and re-adjusted on each tack.

 

[Cayennita]

Not many boats today have downhauls. Main Halyard, outhaul, vang, cunningham, backstay. For masthead boats. Older designs that are masthead rigged need to work on the genoa first. Most of the power comes from there specially when punching through waves. In my J-36 with only a 120% genoa and an IRC main, I get most of the power from the main. Unless it's blowing over 15-17, I hardly use my 8:1 backstay.

 

[RichH]

The frac. P31 with a 150% LP genoa has more sail area for the genoa than for mainsail.
266M vs. 310G sq. ft. ... a quite 'balanced' sailplan for a fractional rig.

In all probability for best trim/shape ---> Main then Genoa then Main again. All this totally depends on the action of a full set of tell tales - luff/midcord/leech + while holding a steady course as read from a row of small 'steering' tell tales on the genoa.

 

[Don Guillette]

Bob Lang: See NEW topic.