adjustable backstay on a masthead sloop why?

[dockmaster]

why would you have an adjustable backstay on a masthead sloop I can see the point with a seven eighths rig but what on earth is going on with a mast head sloop ?? (sorry for my obviouse lack of knowledge in this department)

 

[Phoenix of Hamble]

If she also has a babystay, then you have quite fine control over the mast shape..... extra tension on both will bend the mast in the centre, creating a flatter sail....

Also useful for cranking on the tension for when you are going up wind to reduce forestay sag....

 

[dockmaster]

Ahh obvious when you think about it thanks

 

[roly_voya]

But use with caution, on a fractional rig you can see the mast top bend if you over crank it, on a masthead the first indication may be the mast fot exploding under compression!

 

[dockmaster]

So now I know why the deck has crushed under the mast step !

 

[sailorman]

Wot u need is a Keel Stepped Mast /forums/images/graemlins/ooo.gif

 

[Phoenix of Hamble]

Yep.... perfect for a racing adjustable rig...... and only a small job mopping the water up every time it rains..... /forums/images/graemlins/laugh.gif

 

[sailorman]

Bilge pump does the trick /forums/images/graemlins/wink.gif

 

[Malish]

what is a mast fot?

 

[sailorman]

[ QUOTE ]
what is a mast fot?

[/ QUOTE ]

No Idea /forums/images/graemlins/confused.gif /forums/images/graemlins/grin.gif

 

[dockmaster]

oh Laurel and Hardy have arrived !

 

[bbg]

On a masthead rig the biggest effect that backstay tension has is on forestay sag. As the wind picks up, the forestay sags more (get onto the bow and look up the forestay when you're close hauled - it's remarkable how much it sags).

More sag = baggier sail = more heeling, less drive. When the wind increases, crank the backstay on to limit the sag.

 

[dockmaster]

Once again very helpful thanks

 

[sailorman]

+Baby stay reduces the Draught in the main reducing heeling moment

 

[dockmaster]

So tighten backstay and reduce heel ?

 

[Phoenix of Hamble]

in a breeze yes..... in light winds loosen off to get fuller sails and maintain drive...

There are 1" thick books on this subject so its hard to be definitive in a few lines!

As a rough rule of thumb, full sails tend to have good acceleration but poor top end speed (useful in light winds to make the most of every puff of wind), whereas flat sails are the reverse (useful in a stiff breeze to maximise boat speed).... and a full sail alters the air flow more and hence wider pressure differential between two sides of sail and hence more heeling.... but as above... this is a massive generalisation....

 

[dockmaster]

Guess I will just have to get out there and have a play - dont you just love having a new boat !!

 

[snowleopard]

I recall reading about a large masthead rigged boat with a hydraulic backstay tensioner.... "Look Dad, when I pump this lever the guardrails go slack!"

 

[doris]

It's better to crank on the baby stay followed by the backstay rather than the other way round. Maybe even let off the backstay a tad, crank on the baby stay then wind on the back stay. As soon as you know your best settings use an old batton or similar taped to the b/s adjuster and mark up the optimum settings. You will never do it just by eye each time, especially if it is in anger with another boat chasing you!!

 

[pheonix]

"whats mast fot"

its fot hold sail up nd cach wind

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