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Although forgotten by many and intentionally ignored by others, day shapes are important and must be observed. This is why fines are quite common in the event of an inspection. In details, day shapes refer to Part C of COLREGs, i.e. International Regulations for Preventing Collisions at Sea, stating that by day certain vessels are required in certain situations to exhibit signals having specific geometric shapes (ball, cylinder and cone).

They have the same colour (black) and size (60-cm diameter), however, vessels smaller than 20m can exhibit shapes of reduced dimensions. They shall be visibly hoisted and positioned. As an example, if a vessel is approaching a strait and another vessel exhibiting the black cylinder is crossing ahead, the former vessel will not enter the strait if this impedes the passage of the other vessel. The black ball is hoisted ahead by any vessels at anchor.

Exemptions: vessels of less than 7 meters in length are required to exhibit the lights or shapes prescribed only when at anchor in a narrow channel or transit zone. When the length of the tow exceeds 200 m – measuring from the stern of the towing vessel to the after end of the towed vessel – both vessels shall hoist a diamond shape. In case of vessels not under command two black balls in a vertical line shall be exhibited. Three black balls shall be hoisted by vessels aground. Last but not least, vessels with reduced manoeuvrability shall hoist a ball, a diamond and another ball. In addition, a ball is exhibited ahead in case the same boat is at anchor.

During the day a vessel engaged in fishing, other than trawling (beyond 150 m), shall exhibit a shape consisting of two cones with their apexes together in a vertical line one above the other.

Sailboats and motor boats shall exhibit an inverted cone (point down) ahead. However, it is quite common to notice that many vessels fail to hoist the required shapes and therefore incur penalties.

Foldable and easily stored shapes are available on the market specifically for pleasure boats. They are made of anti-glare black polycarbonate and provided with hoisting holes, like this Black signal cone ( They are practical and economical and ensure compliance with the rules in order to prevent from penalties.

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