Do I Need a Backstay Tensioner ?

[bewitched]

Cruising and racing mean different things to different people.

A backstay adjuster allows you to easily set the rig for different weather and sea conditions and allows you to trim sails appropriate to those conditions.

I can't see how it isn't applicable to cruising.

Sure you can do without it - the boat will still sail. You could also get rid of the vang, the main travellor, jib/genoa car tracks and anything else that enables you to trim the sails. The boat will still sail - albeit very inefficiently most of the time.

And a boat set up like that may suit some cruisers - but not all cruisers - and not me

[MarkJ]

This is an ex-racing boat so unless the mast has been changed to a cruising mast (I doubt it) then it prolly needs backstay adjustment....

.... now technology has changed since I raced, but these days (god I sound old) can't you have a block and tackle with 6 or 8mm Dyneema as the tensioner?

Cost about $200


Would that be OK for a 40 footer?

6mm Dyneema Average Break Load is 3230 kilos
The safe working load (SWL) is usually calculated at 20% of breaking strength
SWL = 646
Purchase say 4:1 = 2584kgs

Is that enough?

[akio.kanemoto]

Originally Posted by MarkJ

This is an ex-racing boat so unless the mast has been changed to a cruising mast (I doubt it) then it prolly needs backstay adjustment....

.... now technology has changed since I raced, but these days (god I sound old) can't you have a block and tackle with 6 or 8mm Dyneema as the tensioner?

Cost about $200


Would that be OK for a 40 footer?

6mm Dyneema Average Break Load is 3230 kilos
The safe working load (SWL) is usually calculated at 20% of breaking strength
SWL = 646
Purchase say 4:1 = 2584kgs

Is that enough?

On this note actually, if I must have a backstay adjuster, I'd probably go for whatever is the easiest to use (and install) then.. which smells like a hydraulic...

8mm backstay wire.. perhaps a Navtec 17...

Bah.

[Jimbo2010]

Originally Posted by MarkJ

This is an ex-racing boat so unless the mast has been changed to a cruising mast (I doubt it) then it prolly needs backstay adjustment....

.... now technology has changed since I raced, but these days (god I sound old) can't you have a block and tackle with 6 or 8mm Dyneema as the tensioner?

Cost about $200


Would that be OK for a 40 footer?

6mm Dyneema Average Break Load is 3230 kilos
The safe working load (SWL) is usually calculated at 20% of breaking strength
SWL = 646
Purchase say 4:1 = 2584kgs

Is that enough?

I don't think so, a straight 4:1 will be too hard to pull.

U need to look at cascading systems perhaps an 8:1 (2*2*2) cascade before the final 6:1 purchase.

Now this will be lees prone to failure than any hydraulic system.

When a seal breaks or hose ruptures on a hydraulic system the backstay will go full length, the whole rig will relax.
I don't know of a way to jury rig it tight till U get to port.

If your in weather the rig can take a beating being loose.

[Stillraining]

Originally Posted by bewitched

Cruising and racing mean different things to different people.

A backstay adjuster allows you to easily set the rig for different weather and sea conditions and allows you to trim sails appropriate to those conditions.

I can't see how it isn't applicable to cruising.

Sure you can do without it - the boat will still sail. You could also get rid of the vang, the main travellor, jib/genoa car tracks and anything else that enables you to trim the sails. The boat will still sail - albeit very inefficiently most of the time.

And a boat set up like that may suit some cruisers - but not all cruisers - and not me

Very Very well said...to the point that I have nothing further to add to aid this discussion along.

Its been a good discussion though.

[Paul Elliott]

Originally Posted by Jimbo2010

Now this will be lees prone to failure than any hydraulic system.

When a seal breaks or hose ruptures on a hydraulic system the backstay will go full length, the whole rig will relax.
I don't know of a way to jury rig it tight till U get to port.

If your in weather the rig can take a beating being loose.

People often jury rig a broken backstay using spare halyards. Of course they then have to reduce sail and still won't have the proper tension, but at least the rig doesn't usually fall down once the jury rig is up.

I read a (true) story where a skipper had fabricated a *long* SS rod with threads and an eye, which he could use to replace a busted hydraulic adjuster. He threaded it into the turnbuckle below the adjuster, and attached the backstay to the eye. In this story they needed to use the thing. Of course they had to secure the mast with halyards first. I think in the story the hydraulic adjuster actually came apart, it didn't just creep out to maximum extension.

It sounds like a good idea, but I don't carry a spare like that. I don't see why you couldn't do the same thing but using hi-tech line and the appropriate end fittings. I carry a few hundred feet of dyneema line, but probably don't have the fittings on board.

FWIW, VALIS originally came with a turnbuckle at the backstay. I added a Navtek adjuster, which lets me tweak the forestay tension and genoa shape. I've also got running backstays to help with staysail stay tension, and to keep the mast in column when we are bouncing around in the swells and wind. The mast is aluminum with double-spreaders, and heavy, and I can definitely bend it, the bend occurring mostly between the lower shrouds and the top.

If I were only cruising, I might not have added the adjuster but instead tuned the rig for average upwind sailing and left it at that. But, I'm pretty casual about performance when I'm in the cruising mindframe. It *is* nice to be able to sail to weather though, and proper sailshape can make a big difference.

[Joli]

Loosing the hydraulics is not a problem.

In this photo you can see the screw and turnbuckle body. Should the cylinder fail the turnbuckle is brought home and the rig is re-tensioned.



Picture showing cylinder, screw and turnbuckle.

Originally Posted by Jimbo2010

When a seal breaks or hose ruptures on a hydraulic system the backstay will go full length, the whole rig will relax.
I don't know of a way to jury rig it tight till U get to port.

[wolfenzee]

My rig was designed 70 or more years ago and gets by quite well with out a tensioner on all points of sail (points 35degress off the wind with out pinching it too much) if I wanted to improve main performance I might get a new main, mine doesn't even have battens.....I guess they are just needed for newer rig designs than need help after they were "fixed".

[akio.kanemoto]

Thanks all for your informative replies. One of the things that really hit home here for me is that some boats are not designed to be under tension all the time.. forever.

Seeing as though mine was a purpose built silly raceboat - I have a feeling that mine is one of those that was designed to be cranked up and bent like a banana.. but then released again after a few days of racing.

I'm not sure what the original mast looked like, but I'm pretty sure that the boat came from the shipyard with the hydraulic backstay adjuster. I've spoken to the manufacturer of the hydraulics (still in business.. wow).. and they say that the panel is approx 30 years old... which is a fair indication that the boat came with it, and just the cylinder/ram was replaced perhaps 10 years ago.

So while I really don't want to complicate my life, I will go and get another hydraulic unit to keep the boat as close as I can to what it started life as (within reason... it's certainly had a wrenching personality shift internally with accomodation!) and once I sail it properly, I can always sell it on ebay later if I decide that I don't need it after all.. at least I'll have options... and it's a decision that will take me closer to having the mast back in.

I'm thinking navtec, since it's all self-contained and quite well represented in the cruising community (at least 10 mins with google makes me think so)..

...I have 8mm backstay wire, so I'll be going for the Navtec 17 which states max wire size of 3/8". Only problem is that the eye in my chainplate tang is only 1/2".. so I'll have to drill it out.. sideways with a hand-drill on the boat since the fitting is glassed in as part of the hull and won't be coming out any time this century.

Also, I will have to shorten the backstay by about 30cm or so. I'm thinking of using a Sta-Lok fitting.

If anybody has any advice/comments on the navtec 17, sta-lok fittings or my enlarging the hole process, I'd appreciate it.

Thanks again!

[bewitched]

Not as good as Joli's system above, but a quick fix precaution is a permanently installed spectra line from chainplate to turnbuckle above hydraulic unit - length is same as hydraulic unit fully off. Will not keep the rig in tension, but will keep it up if you run down when sorting out some sort of jury block & tackle system.

[wolfenzee]

I was asking around and ran into someone who has been sailing most of his 70 years and now races.....he said the backstay tensioner increases the efficiency of the top of the mainsail ...... he also said "you don't really need one if you know how to sail right" he has a $100,000 racing boat (I think it is a J-27).....with no tensioner

[bewitched]

He's wrong

[ozskipper]

Regardless of racing or cruising. A backstay will add forward prebend to the centre of most modern day ( say the last 30 years) masts. This pre bend pulls the centre of the mainsails luff forward. This flattens the sail. This makes it easier in a blow. A lot easier. It will also help with pointing ability on many rigs.

Just because we cruise, doesnt mean we dont want to get there before the sun sets and the bars close!

As someone else said. "Why not remove the vang and traveller if we want to keep our boats basic". The simple answer is, that we would make our massive investments inefficient.

Cheers
Oz

[Jimbo2010]

Originally Posted by wolfenzee

I was asking around and ran into someone who has been sailing most of his 70 years and now races.....he said the backstay tensioner increases the efficiency of the top of the mainsail ...... he also said "you don't really need one if you know how to sail right" he has a $100,000 racing boat (I think it is a J-27).....with no tensioner

Age doesn't = knowledge

The J-27 comes standard with one, by the way it's not 100K nor does that have anything to do with it.

Here's part of the tuning guide from J boats

GENOA TRIM:
In light air, 0-6 knots apparent, the #1 Genoa lead should be set so that the foot of the genoa is about 6-8" off both the chain plates and the top spreader. The halyard should be eased so wrinkles form along the luff. The backstay should be eased all the way to keep the jib full. As the breeze increases the backstay will need to be tightened as will the jib sheet tension...

U found someone that fit your way of thinking which I think is incorrect.

Your statements in this thread indicate your sailing knowledge needs to be expanded, not sure it can be if you're so closed minded.

[MarkJ]

I was on a boat last night with a screw type adjuster. instead of a wheel to wind it there was 2 neat folding handles flush against the backstay. Fine idea and would have to be on the more inexpensive end of the scale.