Do you know the reason for SPREADERS?

[Craig Weis]

Do you know the reason for spreaders on the mast?
I was amazed when I read in the USPS Sail Class Materials that spreaders are up there because...

"The angle formed between a mast and the supporting shrouds is an important factor in determining the compression load on the mast. Compression is the downward force on the mast imposed by tension brought on by the force of the wind.

Shrouds that run directly from the top of the mast to the chain plates form a small angle at the masthead. This small angle increases the compressive force on the mast and could buckle it. To reduce the stresses, small horizontal spars called spreaders are placed part way down the mast. Spreaders increase the angle between the shrouds and the mast at the mast tang and thus reduce compression loads on the mast substantially. On tall masts, two or three sets of spreaders may be used".
Wow, I did not know that. skip.

[B.Hart]

I did not know that! Thanks for sharing skip.                                                                                                                                                                                                              Bill

[Scott Statz]

I think some one (USPS) hasn't done ALL of their homework.  The USPS materials are misleading even for the novice sailor.

The compression load thing is true but not the primary reason for spreaders.  The spreaders change the geometry of the afflicting and conflicting forces on a mast.  Thus preventing the chance of a mast buckling. 

The definition given suggests that by changing the angle of the shrouds, the problem is diminished.  So, in effect, if you ran out riggers and placed your chain plates outboard, and achieve the same stay angel, you would not need the spreaders.  This is not true.  You will see a decrease in the compression load but that's not the critical issue.  The critical issue is the rigidity of the mast. 

Diamond Shrouds address the rigidity issue directly.  Diamond Shrouds are not popular, though very effective, they demonstrate the utility for rigidity in a mast.

This is a very important subject if a novice sailor (racer or cruiser) intends on advancing his knowledge and understanding of his environment.

A sailing vessel needs to be balanced in every force acting upon it.  Think about this, think about where the energy is coming from and where that energy is going.  Now go and enjoy it in your advantage!