Forestay sag

2

[2574]

...
Joined
29 Nov 2002
Messages
6,022
Visit site
Firstly I accept that the title of this post could lead to considerable myrth! But I'd also appreciate some serious responses!

Out sailing at the weekend in typically 25 to 28 kts and our 130% genoa (with 2 rolls in the furler) was causing our forestay to sag what seemed to be quite alarmingly. It was difficult to assess by eye the distance from centreline but I would say it was being pushed at least 9 inches to leeward at mid height between tack and masthead. Is that normal? When back in the marina I compared (unscientifically) our forestay tension to other boats and it seemed about right. I did put a little backstay tension on whilst sailing but it made precious little difference.

Any views?

rob
 
Doesn't sound out of the ordinary to me. Anything up to 12 inches on a 40 footer would not be unreasonable I would have thought.
 
This sounds like a lot of sag, but shouldn't be too much of a problem unless going to windward, in which case haul the backstay fairly tight and you should point better. Our boat responds well to a bit of backstay tension when hard on the wind, the problem is remembering to relax it afterwards.

- Nick
 
Also, try some additional kicker tension, as this may hold the top of the mast slightly more firmly by tightening the leech up a bit...... and do you have a babystay?.... if so, putting some tension on it, may well pull the middle of the mast forward, and allow the top section to hold the load more firmly as well as flatten the main for upwind work...... all IMHO... and only tweaking.....

FWIW, my foretay sags quite a bit too.....
 
Sounds about right in a 40' masthead cruiser and IMHO it should not be an issue provided your headsails are cut to accomodate the sag you've got in normal breezes.

I'd check that with your sailmaker.

If the sag only appears with stronger headwinds, and if you are cranking on the backstay of a masthead (assumption) rig and it is making no difference to that forestay sag, I'd suggest you also look up at your mast.......

If it is not bending backward (and thereby taking up your forestay tension) then it could be bending forward (inverting) - or setting up a risky compression load on the mast itself.

Cheers

JOHN
 
going upwind my mast is akin to a long bow with 200 Lb pull on it.
just "wang-up " the back stay till its like a rod /forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif
there agiian Chentlemen dont go to windward do they /forums/images/graemlins/confused.gif
 
its not easy to "Wang Up" the backstay on all boats - such as ours. It would be a case of tightening the bottle screw with spanners etc while sailing along. Then when sailing off the wind, maybe having to slacken it again.

I suspect that the original poster has the same problem.
 
[ QUOTE ]
its not easy to "Wang Up" the backstay on all boats - such as ours. It would be a case of tightening the bottle screw with spanners etc while sailing along. Then when sailing off the wind, maybe having to slacken it again.

I suspect that the original poster has the same problem.

[/ QUOTE ]If you dont have a bendy mast with instant backstay tensioning, then you can only really push up the tension to the max recommended (20% ? I seem to remember, but more if you are a racer and dont mind changing your rigging more often). That means you dont have too much sag** at the top end of conditions, and perhaps a bit too much fullness in light conditions, but hey, cruisers put their engines on when doing 1.5-2kts on the wind /forums/images/graemlins/cool.gif

At least, that's my take on it, and I cant tweak mine either.

** trouble with too much sag is fullness induced into the front of the genoa just when you really would rather not have it, plus it tends to make the mast pant.
 
I think it depends on your rig set up. We have runners on our boat so forestay tension is never really a problem. Putting too much tension on is what worries me. /forums/images/graemlins/crazy.gif

On my Dad's old boat it was a fixed backstay, and its really a case of finding out what works for you in a variety of conditions. I would speak to a Nauticat dealer, or perhaps some other Nauticat 39 owners.

In my experience nothing makes a pint disappear faster than a discussion about rig tension! /forums/images/graemlins/smile.gif

John
 
You must log in or register to reply here.

Share this page

Top