Unmorph at the top of the jump to touch the transition. A crouch jump can help.

Requires:

"canSuitlessMaridia"
"canTrickySpringBallJump"
{
  "or": [
    "h_underwaterCrouchJump",
    "canTrickyJump"
  ]
}

Unlocks doors:

{"types":["ammo"],"requires":[]}