"Saw two warping winches on a large yacht yesterday and no sign of deck fatigue or bent over winch."
Warping is an exercise where the winches are used to re-position the boat.
On a dock or aground , any stress is from its being operated.
Seldom will deck gear be strong enough to harm itself.
Anchored in a small Thunder storm the loads passed to the deck come from the boats movement being checked.
This can easily be far more energy than simple warping loads.