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The ladders are made by threading and fixing a series of hardwood, machined steps, each not more than 400 mm × 115 mm × 25 mm (15.75 in × 4.53 in × 0.98 in), onto two pairs of minimum 18 mm (0.71 in) diameter manila ropes, and binding each step to the ropes at 310 mm (12 in) (+- 5 mm, 0.20 in) intervals.
A pilot ladder has specific regulations on step size, spacing and the use of spreaders. It is the use of spreaders (long treads that extend well past the vertical ropes) in a pilot ladder that distinguishes it from a Jacob's ladder. When not being used, the ladder is stowed away, usually rolled up, rather than left hanging.
An extension ladder. A ladder is a vertical or inclined set of rungs or steps commonly used for climbing or descending. There are two types: rigid ladders that are self-supporting or that may be leaned against a vertical surface such as a wall, and rollable ladders, such as those made of rope or aluminium, that may be hung from the top.
The initial setting operation includes fixing the theodolite on a tripod, along with approximate levelling and centering over the station mark.For setting up the instrument, the tripod is placed over the station with its legs widely spread so that the centre of the tripod head lies above the station point and its head approximately level (by eye estimation).
This means that if there is a 4" (100 mm) gutter projecting from the side of a building, a fixed ladder would have to have standoff brackets that were at least 11" (7" + 4") (280 mm) in length. Cages: Cages are optional for fixed ladders with a floor to floor elevation of less than 20' (6100 mm). They are often available for ladders with ...
A tripod is a portable three-legged frame or stand, used as a platform for supporting the weight and maintaining the stability of some other object. The three-legged (triangular stance) design provides good stability against gravitational loads as well as horizontal shear forces , and better leverage for resisting tipping over due to lateral ...
1. To step onto, climb onto or otherwise enter a vessel. 2. The side of a vessel. 3. The distance a sailing vessel runs between tacks when working to windward. boat 1. Any small craft or vessel designed to float on and provide transport over or under water. 2. Naval slang for a submarine of any size. 3.
The tread depth of a step is measured from the edge of the nosing to the vertical riser; if the steps have no nosing, it is the same as the going; otherwise it is the going plus the extent of one nosing. The going of a step is measured from the edge of the nosing to the edge of nosing in plan view. A person using the stairs would move this ...