Spreader question

[wscherf]

Was up at the Port Townsend show this past weekend. Looking at the small dinghy rigs since I'm building one (Arch Davis' Ace 14). Standing rigging called out Arch's design is dead simple - forestay and a pair of shrouds - no spreaders.

A few of the comparable sized boats in the show were sporting spreaders, although the shrouds were dead straight or showed the tiniest angle. I thought the purpose of the spreaders was to reduce the compressive load on the mast and the corresponding force on the chainplates by increasing the angle between shroud and mast. So what would the purpose of a spreader be on a straight shroud?

[donald branscom]

Prevents the mast from bending excessivly.

[Varna]

In a basic simple strut spreader as you mention with no geometry involved the strut acts more as a hanger or connector and allows a much thinner lighter mast section since the panel length is reduced.
Most modern dinghy classes have adjustable sreaders with fore and aft sweep and lateral adjustment giving much tuning tweaking to the mast/sail for various sea and wind conditions. I do wonder about the air foil spreaders being a bit over kill at non-airborne velocities. Look fast anyway and that sells 'Stuff' though I guess.