Why does my floating character drop through water at low speeds?

Water plugin Buoyancy uses velocity-driven sampling. Slow movers under-sample. Increase Pontoon count, raise Velocity Scale, and tick at higher rate via Tick Group.

Can I use Buoyancy on a CharacterMovementComponent?

Buoyancy is for Pawn-with-physics or Actor with PhysicsBody. Default Character uses CMC which doesn't simulate. Switch to a custom physics-based Pawn for boats.

Water collision profile?

Water Body needs a profile that lets pontoons sample the surface (Pawn-Block or custom). Verify in Water Body details.

Fix: Unreal Water Character Skips Buoyancy Steps

Quick answer: 4+ Pontoons distributed under hull, Buoyancy Coefficient ~1.5, Velocity Scale ~1.5, Water Body profile lets pontoons sample.

Boat works at high speed but sinks at idle. Velocity-driven buoyancy under-samples below a threshold; slow movers don’t accumulate enough lift force.

The Fix

BoatActor:
  BuoyancyComponent:
    Pontoons:                 4 distributed
    Buoyancy Coefficient:     1.5
    Velocity Scale:           1.5
    Max Velocity:              2000
  StaticMeshComponent (root):
    Simulate Physics:          true
    Mass (kg):                 800
  Tick Group:                 PrePhysics

Velocity Scale boosts the lift force at low velocities. Mass set explicitly avoids auto-mass producing tiny floats.

Verifying

Drop boat into water at zero velocity. Floats at expected depth, doesn’t sink. Push around — rocks naturally.

“Velocity Scale up. Pontoons spread. Boat floats idle.”

Related Issues

For Water Body buoyancy, see water buoyancy. For physics asset trace, see physics trace.

Velocity Scale. Pontoons. Float still.