HM standing Rigging. Why use DeadEyes?

[Brion Toss]

Hello,
Turnbuckles and deadeyes are both means to apply mechanical advantage to tension rigging. Turnbuckles are simply more powerful, a lot more powerful, and use less effort to apply their power. That's why they've displaced deadeyes for most applications. On boats where tension isn't so important, like multihulls, for example, where hull flexion prevents high standing loads, deadeyes are fast, cheap, simple, etc. On most contemporary monohulls, the presence of deadeyes might reflect how tricky it is to get the stays the right length when they're made from Spectra...
Fair leads,
Brion Toss