Mistakes in chaining:
Mistakes are generally made by inexperienced chairmen. These can be avoided by careful working. The following are the common mistakes made in the field :-
(i) Miscounting the Chain Length. This is the most serious mistake and occurs due to wrong counting or due to loss of arrow. It can be guarded against if leader takes full number (usually ten) of arrows at the commencement of work and at each transfer, the follower and the leader count them.
(ii) Displacement of Arrows. When once an arrow is displaced, it may not be replaced correctly. To avoid this, the end of the chain length should be marked both by scratching a cross on the ground and fixing an arrow.
(iii) Misreading. This happens due to reading from the wrong end of the chain e.g. reading 8 m for 12 m in 20m chain. It can be avoided by carefully noticing the position of the central tag.
(iv) Some mistakes like trasposing figures e.g. 58.38 for 58.83; reading tape upside down e.g. 6 for 9 or 68 for 89; calling numbers wrongly e.g. calling 20.1 as 21 and wrong booking e.g. 264 for 246 are also common. these can be avoided by care and good power of judgement of the surveyor.