Dry Dock - Anchor Inspection and Defects

 Anchor

 General

Anchor  Terminology

Inspections of anchors and anchor chains are not the requirements of the Docking Survey but they are an inspection items in a Special Survey and Intermediate Survey. But the inspection of the anchor andchaincable are carried out customary at the Docking Survey. At the Docking Survey  anchors andanchorchaincables are  ranged on the dock floor and the surveyor carry out the survey.  Hereinafter explain the survey points and the examples of damage and repair methods.

Survey items

·         Anchors – examination for defects

·         chain ranging- with links and fastening arrangements examination

·         Chain lockers and chain Stoppers.

Anchor Defects and repairs

(1) Break and Crack

Small cracks sometimes appears at the corners of the hole in the under surface of the crown. This part should be carefuly inspected after sludge is removed and cleaned. Depending on the degree of damage, repair can be carried out out by re welding.

Broken Shank

 

Broken Fluke

broken piece

crack on shank

Crack on Flike

Fluke cracks near pin in center

 

(2) Bend
When the anchor is resting on the dock floor, sometimes both fluke ends do not touch to the floor, it means, one fluke is raised higher than the other, then the one arm is bent. Depending on the degree of the bend, the anchor should be send to the manufacturer for repairing or it should be renewed. In this case also the outstanding recommendation is appointed

3. Wear and tear
  Wear to anchor ring
The maximum wear to the anchor ring appears at the pin.

 If the wear is only at the pin, then only the pin may be renewed using an approved material (forged steel, cast steel or rolled steel round bar); but in most cases the hole in the anchor ring is also worn out, therefore, the complete set is generally replaced.

During replacement, a proof test for the complete anchor should be carried out; however, if the anchor is repaired at the shipyard, sometimes this test is omitted as the testing equipment is not available. Moreover, the pins at both ends became loose and they develop play frequently. If this happens, the end of the pin should be hammered while heating to tighten the pin.

 

Abrasion / Wear to shank
The shank often wears out at the bell—mouth position. Later when the shank and bell—mouth adopt themselves, the wear is reduced, so repairs by welding is not necessary. Excessive shank wear either necessitates build-up by same material or replacement.

Worn out of crown pin and defective crown pin
The crown pin connecting the shank and the crown wears out in the aged ship but generally the wear does not reach a stage where it needs replacement. However, it is recommended that the condition of the pin is to be inspected after cleaning.

A considerable amount of mud accumulates near the crown pin. If the mud is not removed from a and b, flaws cannot be detected.