A vessel constrained by her draft Rule 3. (h)The term "vessel constrained by her draft" means a power-driven vessel which because of her draft in relation to the available depth and width of navigable water is severely restricted in her ability to deviate from the course she is following. [Int] may, in addition to the lights prescribed for power-driven vessels Rule 3 (b)The term 'power-driven vessel' means any vessel propelled by machinery; in Rule 23, exhibit where they can best be seen three all-round Rule 21. (e) "All-round light" means a light showing an unbroken light over an arc of the horizon of 360 degrees. red lights in a vertical line, or a cylinder.