BS ISO 799-1:2019 pdf download – Ships and marine technology — Pilot ladders Part 1: Design and specification
5.6 Each pair of side ropes shall be secured together, both above and below each step, with specially designed step fixtures (chocks or widgets) which hold each step level when the ladder is hanging freely. Alternative acceptable arrangements are shown in Figure 1B.
5.7 If step fixtures are used to secure the side ropes and hold the step in place, the step fixtures shall not extend above or below the step surfaces by more than a distance equal to 0,7 × W (where W is the width of the step), so that the step is not prevented from rolling if caught between a boat and the hull of the ship.
5.8 If a seizing method is used to secure steps and side ropes, step fixtures shall be used above and below the step. The step fixtures shall be designed to lead and support the side ropes from the step to the point above or below the step where the side ropes are seized together. The step fixtures shall be designed so that they stay in place when the ladder is rolled or the step is turned. 5.9 The clear space between the side ropes on one side of the ladder and those on the other side shall be at least 400 mm, see Figure 2 and Figure 3. This distance shall be uniform throughout the length of the ladder, See Figure 1A.
5.10 Each side rope shall be arranged so that, when the ladder is in use against the vertical hull of a ship, the side rope cannot come in contact with the ship’s side.
5.11 A securing rope, if used to aid in rigging the ladder, shall be shackled at the upper end of each side rope of the ladder, as shown in Figure 1A and Figure 1B. Both securing ropes shall be of equal length and shall have a breaking strength of at least 48 kN. Securing ropes shall be fitted with a thimble. The other end shall be treated to prevent fraying. A suitable method to prevent fraying is a whipping.
5.12 The length of each securing rope shall be at least 3 m. The securing rope shall not be directly cut or spliced to the side rope.
5.13 The spacing from the top of one step to the top of the next step shall be 330 ± 20 mm, and shall be uniform throughout the length of the ladder. If there is no securing rope at the upper end of the ladder as specified by purchaser, the splice eyelet or sling shall be at least 3 m above the upper end of the top step. See Figure 1B. 5.14 Each step shall be of one-piece construction, of either hardwood or resilient plastic or rubber material complying with the applicable requirements of Clause 4.
5.15 The top face of each step shall be in rectangular form with a width not less than 115 mm, and its surface is grooved or patterned, or of a textured non-skid type. The step surface shall be designed so that it does not retain water. A textured non-skid surface shall be integral with the step and shall be either moulded or cut into the step with the nominal depth of 3 mm. Non-skid adhesive sheeting may not be used. See Figure 2.
5.16 Each step shall be at least 25 mm thick at its thinnest point. In determining this thickness, the depth of grooves in the top face of the step, the diameter of any hole extending from one side of the step to the other, and the thickness of any non-skid treatment shall not be included. See Figure 2.
5.17 Each step shall be arranged so that it can bear on the vertical hull of the ship when the ladder is in use.
5.18 The manufacturer shall offer replacement steps, including replacement spreader steps, for the ladder that can replace a removed step, without the need for unstringing and restringing the ladder. Replacement steps shall meet all of the requirements in this document for steps, and each step shall be supplied with all parts necessary to install the step in the ladder. 5.19 Each pilot ladder shall be capable of being rolled up for storage. Each ladder shall be capable of unrolling freely and hanging vertically.
5.20 The four lowest steps of the ladder shall be made only of resilient synthetic or rubber materials. The rest of the ladder steps shall be of either hardwood or synthetic material.
5.21 For the convenience of manoeuvring the pilot ladder to the required height, the permanent marking is made every three steps (approximately every 1 m). 5.22 Each pilot ladder with more than five steps shall have one or more spreader steps at the positions indicated in Table 1.
5.23 Each spreader step shall meet the requirements for other ladder steps, except that each spreader step shall be at least 1,8 m long. See Figure 3.BS ISO 799-1 pdf download.