Rigging Stages, Bosun s Chair, and Rope Ladders

Transcription

1 Contents Rigging Stages, Bosun s Chair, and Rope Ladders 3 Introduction 3 Rigging a stage 4 Rigging a Bosun s chair 5 Portable ladders 7 Gangways 8 Nautical Knowledge Ladders and Stages 1

2 2 Nautical Knowledge Ladders and Stages

3 Rigging Stages, Bosun s Chair, and Rope Ladders Introduction This section is not about lifting weights, but about lifting people. If the rules in lifting weight had to be narrowed to one, it probably would be to keep out of the way of loads. But when the load is people, they can t do that. So stick to the safety rules! Practical and closely supervised training is required for such operations, so be familiar with the basics given here. There are various ways to rig staging for a vessel s maintenance. On board any vessel there is little space to set up proper scaffolding and staging, and also there will always be obstacles on deck to contend with that make it difficult to set up staging. So there will generally be a good chance that you will have to compromise or jury-rig the staging. The easiest way to rig staging on a vessel is to use simple scaffolding, which can only be set up one way because of the arranged lengths and clips etc. The most important thing to remember about setting scaffolding up is that the base must be level and sturdy. After you set up a sturdy base, build the scaffolding to the height you require, going a little bit higher so you can fit guard rails. Then, using rigged lines, pull the planking up and place it atop the scaffolding and tie it down with lashing cord. Ensure you have a good working platform. Also ensure you fit the guard rails, which should be just above waist level. Because most vessels will not have the deck space to allow you to do this, you will have to use other parts of the ship to support the planking. There are two ways to do this: Lash a plank between the port and starboard shrouds by letting it rest on top of a ratline (a rope step lashed between shrouds). Then lash it in place and put safety lines around the entire area. Put a plank onto part of the superstructure of the ship, and then take the other end to a ratline or shroud and lash it in place. Again, fit safety lines and lash the planks down. Nautical Knowledge Ladders and Stages 3

4 Those are the two basic stagings you will use on a ship: there are others like the flying stage and suspended stage which are explained in your text, but the key point is that there is no set way to rig up staging on a vessel, because each vessel is different and each situation will have to be assessed to see which is the best way to support planking. Just remember that safety is the key, and the lashings and support lines must be made fast extremely well and secure. Rigging a stage The practical handiest size line for a stage rope is 20mm. This is known as a gantline. It must be long enough to reach the waterline on the bight when working over the ship s side. One method of securing the end of the stage is shown below. Figure 1 In the above method the rope tail is made fast to the standing part after the hitch is completed, using a bowline. If the stage is extra long, it is advisable to rig a centre line to prevent sagging in the middle. The standing part should be reeved through a lizard, shackle or best of all a tail block to enable it to be lowered and adjusted by those working from the stage. Take two full turns of the hauling part around the end of the stage and one full turn around the horn as a means of lowering. 4 Nautical Knowledge Ladders and Stages

5 Precautions Check stage for defects. Inspect all lines and fittings. Correctly rig the stage. Load test the stage to four times the intended load. Gantlines must trail in the water to be used as lifelines. Stages should only be rigged over water. Do not use while underway. Always set down before raising and lowering. Rig a rope ladder for access. Be positively tended and have a life buoy available. Rigging a Bosun s chair In most work done aloft a bosun s chair and gantline is used, the gantline is always attached to the chair by means of a double sheet bend with the end seized to the standing part (Figure 2). The gantline should be reeved through a tail block or lizard for ease of hauling and lowering oneself. How to make a lowering hitch while on a Bosun s chair A long bight of the hauling part is pulled through the strop of the chair, passed over the head and allowed to drop behind to the feet. It is then passed under the feet and brought to the front. The slack on the hauling part is pulled tight forming the hitch. When ready to lower, render slack on the hauling part through the hitch, which it will easily do. The practice of holding on with one hand and making the lowering hitch with the other hand is dangerous. Nautical Knowledge Ladders and Stages 5

6 Figure 2: Bosun s chair Note: Grip with hand and seize both parts of the gantline together before making the lowering hitch. Precautions Check bosun s chair for defects. Inspect all lines and fittings. Corrrectly rig the gantline. Load test four to five times the intended load. When hauling aloft in a bosun s chair it should be done by hand. 6 Nautical Knowledge Ladders and Stages

7 Figure 3: Riding a stay When riding a stay ensure the bow of the shackle rides the stay not the pin. Always seize (mouse) the shackle pin. Wear a safety harness if more than two metres aloft. The person working aloft should make sure all tools have safety lines attached to the chair. A safety precaution while in the chair is to have a harness attached to the standing rigging of the vessel. This will stop you from swinging around when the ship moves about. You can also use somebody on deck to lower you when need, but it must be made clear that they must take caution and have a turn with the halyard around a pin or something sturdy. Also, it is recommended that you use a purchased bosun s chair rather than a home-made one! Portable ladders Rope ladders/side ladders are used to access stages over the vessels side, over hatch coamings to access parts of a hold etc. They are light and handy ladders easily carried around the decks. The top of the ladder can be left with the rope ends whipped or a thimble can be used. This enables it to be shackled to a boom if necessary. Nautical Knowledge Ladders and Stages 7

8 Figure 4 Gangways Gangways are used for the movement of people from the ship to shore, or vice versa. Things you must consider are tide movement, surge, weight of the users, and the length, height and angle of the gangway. Most importantly, ensure that the gangway is firmly secured to the ship, so that it does not move on the deck and cannot fall away from the ship. The gangway should be on wheels and must be able to withstand a great deal of weight. You must also watch the rise and fall of the tide, because you will have to adjust the height of the gangway accordingly. A gangway must have a hand-rail that is waist-high and rigid. It should also have slats which go across the planking every 400cm or so, and the planking should have a non-skid surface. The lifting cables for the gangway should be inspected regularly and greased. All the different types of gangways must be fitted with a safety net that is attached at four points: two on the ship and two at the bottom of the gangway or dock wall. The net should be tight, made from a rope with a minimum thickness of 18 mm, and it should be a little lower in the middle section of the net than the outer edges. 8 Nautical Knowledge Ladders and Stages

9 Check your progress 1 List the precautions for rigging a stage. 2 Briefly list safety precautions for working in a bosuns chair. Check your answers with those given at the end of this learning resource. Nautical Knowledge Ladders and Stages 9