Q&A 2018-008
Rule 53, Skin Friction
Actions that can be performed and products that may be applied on a boat’s hull without breaking rule 53
Situation
Rule 53, SKIN FRICTION, states:
A boat shall not eject or release a substance, such as a polymer, or have specially textured surfaces that could improve the character of the flow of water inside the boundary layer.
Question
What actions can be performed on a boat’s hull and what products may be applied without breaking rule 53?
Answer
In compliance with rule 53:
  • Paint, polish and antifouling on the hull, provided that it has a smooth and continuous surface texture.
  • Sanding of the hull, provided that it has a smooth and continuous surface texture.
  • A sticker or other hull film with a smooth and continuous surface texture, including the edges of the sticker or film.
  • Any other application, provided that it has a smooth and continuous surface texture.
Not in compliance with rule 53:
  • Ejecting or releasing a substance at or near the hull surface
  • A hull application that has a varied texture surface which may include features or other distinct textures to modify or trip the boundary layer at that specific point.
Attention is drawn to Class Rules that may have individual limitations on sanding and hull applications.