forestay tension

[nathanlee]

Hi all,

My rig was looking a bit sad, so I've sorted it all out. The exception being the forestay. I have roller furling, so I'm not sure how to check it.

Basically, it doesn't seem very tight as the whole lot can move a few inches side to side by shaking the boat.

How do I know when it's at the right tension?

Cheers,

Nathan

 

[pikeyrm]

give it the twang test. like a guitar not the best way but the cheapest

 

[Salty John]

You can't check forestay tension with roller furling, you need to check that your backstay tension is high enough. Unless you have one of a small variety of catamarans, the forestay tension will always exceed the backstay tension by virtue of the different angles they make.
If you crank your backstay tension up to 20% of the wire breaking strain you will have about as much tension as you can get on the fore stay. 25% of wire breaking strain is absolute max.
If getting adequate forestay tension via tensioning the backstay rakes your mast too far back you need to shorten your forestay.

 

[flaming]

[ QUOTE ]

How do I know when it's at the right tension?


[/ QUOTE ]

In short, go sailing.

The forestay tension effects the shape of the genoa. More tension = better pointing but less power.

In an ideal world you would tension it as the wind increased, but this is not really practical on a cruising boat. So most cruising boats are set up with the forestay quite tight, as this makes sailing in stronger winds easier, and unlike racers cruisers don't often try and sail in very light winds, that's what the engine is for...

So try a few settings, ideally in "fresh" conditions and see what seems to work.

 

[Pye_End]

Sometimes getting a tight forestay is not all that obvious - eg. you may need to make sure that the mast is reaonably straight when you need it - ie sailing on the wind. Tightening the backstay is your first port of call, but depending on the rig it is not the only one.

 

[matelot]

Saltyjohn is right. Your rig is designed to give the correct forestay tension if the backstay and all other stays are correct. So just do all other stays

 

[absit_omen]

Handy book to have is 'Sail and Rig Tuning' by Ivar Dedekam.

 

[ditchcrawler]

Is it not the halyard tension that effects the shape of the genoa as much as the forestay tension ?.I appreciate with roller reefing the need to have a tight forestay,although some systems wont roll if the forestay is too tight.

 

[saltwater_gypsy]

I think about 6inches of deflection on firm pull is a good starting point.

 

[Norman_E]

It is usually the halyard being too tight that causes furling problems, but very often it is a partially seized top swivel that is really to blame. Another cause connected with the top swivel being stiff to turn is the halyard getting wrapped round the forestay above the furler. The only way to prevent that is to ensure that the halyard is led at a good angle to the forestay. On my boat it emerges right at the top, from a sheave in the mast crane, but is led through a fairlead a foot or so lower down on the front face of the mast to increase the angle. The fairlead was fitted by my rigger.