Remove isBoat, see #123

js/buoyancy/model/Boat.ts

@@ -119,13 +119,6 @@ export default class Boat extends ApplicationsMass {
     this.basin.liquidYInterpolatedProperty.setRatio( interpolationRatio );
   }
 
-  /**
-   * Returns whether this is a boat (as more complicated handling is needed in this case).
-   */
-  public override isBoat(): boolean {
-    return true;
-  }
-
   /**
    * Called after a engine-physics-model step once before doing other operations (like computing buoyant forces,
    * displacement, etc.) so that it can set high-performance flags used for this purpose.

js/common/model/Mass.ts

@@ -521,13 +521,6 @@ export default abstract class Mass extends PhetioObject {
     this.stepTop = 0; // maxmimum y value of the mass
   }
 
-  /**
-   * Returns whether this is a boat (as more complicated handling is needed in this case).
-   */
-  public isBoat(): boolean {
-    return false;
-  }
-
   /**
    * Returns the bounds of this mass.
    */

js/common/view/DebugView.ts

@@ -147,7 +147,7 @@ export default class DebugView extends Node {
     } );
     this.poolVolumePath.shape = poolVolumeShape;
 
-    const boat = this.model.masses.find( mass => mass.isBoat() );
+    const boat = this.model.masses.find( mass => mass instanceof Boat );
     if ( boat instanceof Boat ) {
       const boatYValues = _.range( boat.stepBottom, boat.stepTop, 0.002 );