You don't have one on Solstice outside a specific quest at Li-Xal Pass. You'll get one if you do that quest, and after that, it will be gone again. If you try to get up there outside the quest, a message box will show up, but nothing about that can be done.
@Syldras | PC | EU The forceful expression of will gives true honor to the Ancestors.
Sarayn Andrethi, Telvanni mage (Main)
Darvasa Andrethi, his "I'm NOT a Necromancer!" sister
Malacar Sunavarlas, Altmer Ayleid vampire
Soris Rethandus, a Sleeper not yet awake
The "grapple bow" isn't actually an object you can use and keep. It gets handed to you for certain quests that use grapple points, then it disappears after.