Not sure whether it’s true, exactly, but from my experience with tilting my glasses, they don’t roll across a surface; they do rotate, or rock, but don’t spill unless overfilled.
I never took mine on a sailboat, nor did I take any others, so I can’t compare. However, I can say round bottomed cups are harder to spill than regular ones.
Not sure whether it’s true, exactly, but from my experience with tilting my glasses, they don’t roll across a surface; they do rotate, or rock, but don’t spill unless overfilled.
I never took mine on a sailboat, nor did I take any others, so I can’t compare. However, I can say round bottomed cups are harder to spill than regular ones.