Trench of Watery Depths

When this defends, you may pitch a blue card from your graveyard.

Blade Break

Rulings

From the Compendium of Rathe release notes

Trench of Watery Depth’s first ability triggers when it becomes a defending card on the combat chain. This is an optional effect: you choose to pitch any blue card from your graveyard when the triggered effect resolves.
You cannot pitch a blue card that is face-down in your graveyard due to this effect.

Keyword notes

Bladebreak - Equipment that are fragile and break after being used to defend. If you defend with a card with Blade Break, destroy it when the combat chain closes.

When you defend with a card it remains on the combat chain until the chain closes, therefore you cannot defend with an equipment multiple times on the same combat chain.
When this card is destroyed, it is sent to your graveyard.
The ability becomes a layer on the chain when the combat chain closes.
The Blade Break ability becomes a layer on the chain when the combat chain closes.
The ability goes on the stack when the combat chain closes.

All keywords

ClassPirate

TypeEquipment

SubtypesChest

Defense1

KeywordsBlade Break

SetsPEN