Ever wondered why do we sometimes have both the anchors of different lengths. It is not very uncommon to notice 10 shackles on one anchor while 11 shackles on other one. All the requirements concerning anchor onboard are formulated in the guidelines issued by International association of international classification (IACS). These requirements include requirements for anchor weight, diameter and steel grade for the stud link of the chain cable and the length of the anchor chain etc.

Anchor ship

All these requirements are governed by something called “Equipment number”. If you would have seen the anchor certificate generally issued during yard delivery of the vessel, you would find the equipment number on that certificate.

Equipment number is calculated by formula

equipment number

As per the equipment number, the total length of the anchor chain is given. So if say, for a particular equipment number, the minimum length of the cable required is 21 shackles, one side of the anchor is given 10 shackles and the other one 11 shackles. Below is the table that shows how equipment number corresponds to the particulars of the anchors onboard.

Anchor length

 

Did you find this information useful ? Let your views flow in the comments below. Meanwhile wishing you all fair winds and following seas.

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Capt Rajeev Jassal

About Capt Rajeev Jassal

Capt. Rajeev Jassal has sailed for over 19 years mainly on crude oil, product and chemical tankers. He holds MBA in shipping & Logistics degree from London. He has done extensive research on quantitatively measuring Safety culture onboard and safety climate ashore which he believes is the most important element for safer shipping.

7 Comments

mohamed sharif saleh
mohamed sharif saleh
Sep 25, 2016

Good Day you always bright star Capt Rajeev Jassal

Rajeev Jassal
Rajeev Jassal
Sep 26, 2016

Thanks for the good words Mohamed..

VIKAS V MISHRA
VIKAS V MISHRA
Sep 27, 2016

but sir where do we find the length of the chain is mentioned...? i mean there must be a certificate for this ?????

Rajeev Jassal
Rajeev Jassal
Sep 29, 2016

There is no certificate required for this. The number of shackles onboard is mentioned in the manoeuvring booklet and wheelhouse poster.

Drake
Drake
May 9, 2017

One more reason of y d anchor chain is different on port at starboard is because of open sea mooring

Amin
Amin
Oct 18, 2016

Hi dear sir would you please explain the ( B ) in the formula?

pritam
pritam
May 14, 2017

Apart from the usefull information u had provided above i have two querry sir. 1 ) why port anchor have 10 shackle and stbd 9 shackle 2) why stbd anchor is called weather anchor.

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