* Scope of Application

This document specifies the shape characteristics of the top mark with different shapes, such as the can shape, the conical shape, the spherical shape , the "X" shape and the cross shape. What's more, it also specifies the shape requirements of the pillar buoy and the bacilliform buoy.

This document is applicable to all buoys in the China Sea Area with its ports and sea estuaries (  the beacon ship, large navigation buoys and ice buoys are not included ) and fixed marks in the water.

*General provisions

1) The shape characteristics of buoys and fixed marks in the water with the painting method should comply with the relevant regulations of GB4696. The surface colors should comply with the relevant regulations of GB17381.

2)The Shape characteristics of buoys should be displayed in one or more forms such as top markers, lookout plates, and body shapes. except the "X"shape and the cross shape of top mark, all the displayed shape features should be the same shape when viewed from any horizontal direction.

3) Buoy top marks, plates and shapes can be partially hollowed out, and the area of the hollowed out part should not be bigger than one-third of the total area, and should be evenly distributed

4) The shape characteristics of fixed marks in the water should be displayed in one or more forms such as top marks, lookout plates, and shapes, and when using top labels or lookouts, its specifications and dimensions should not be smaller than the top marks or lookout plates of buoys set up in the same waters.

5) The top mark should not be obscured by structures and navigation equipment, and it should be in the position of the central axis of the buoy.

* The shape characteristics of conical shape.

1)When displaying the conical shape feature of a buoy with a top mark, the maximum vertical profile of the top mark should be an isosceles triangle. The diameter of the cone bottom of the cone should be 0.25 to 0.30 of the diameter of the float, The cone height should be 0.9% of the cone bottom diameter. The height of the support rod should be 0.35 to 0.60 of the diameter of the cone bottom, the spacing between the two top marks should be 0.25 to 0.5 of the diameter of the cone bottom when the buoys are with two top marks. please check the detail information as picture below:

2) When using a lookout plate to represent the conical shape characteristics of a buoy, the maximum vertical profile of the lookout plate and the bracket should be an approximate isosceles triangle, and the overall shape characteristics should have a conical feature. The two waists of the lookout plate should be in an arc shape, the radius of curvature of each segment should not be less than the length of the bottom edge, the length of the bottom edge should not be less than 0.70 of the diameter of the float, and the height H should be 0.90 to 1.50 times the length of the bottom edge. please check the detail information as the picture below:

3)When using the shape to represent the conical shape characteristics of the buoy, the maximum vertical profile of the shape should be an approximate isosceles triangle, the overall shape display should have a conical feature, and the height should be 0.9 to 1.3 times the average diameter of the cone. please check the picture below:

please check more information on part Ⅱ