Most mariners can tell you the significance of a ship’s IMO number but few know how the number is chosen. One of the guys mathematicians over at koti.mbnet.fi thinks he’s figured it out:
IMO Numbers are made up of letters IMO and seven decimal digits.
- The digits to be checked are weighted from right to left by 2, 3, 4, 5, 6 and 7.
- Products are added up.
- The sum is divided by 10. The remainder is the check digit.
Example: IMO 9074729 (Pacific Frontier, Hong Kong)
9 0 7 4 7 2 9 7 6 5 4 3 2 63 0 35 16 21 4 = 139 -> 9The method could also be described by saying that the weighting factors are 3..8 from left to right, and the check digit is the digit that you need to add to the sum to make it evenly divisible by 10.
If anyone is a mathematician or cryptologist and can verify this please leave a comment below.
So what is an IMO Number anyway? Triton’s Tells Us:
As a result of the attack on the USS Cole, the events of Sept. 11, 2001 and the suicide bombing of the oil tanker Limburg, the IMO held a Diplomatic Conference on Maritime Security in December 2002. At the conference, it adopted a number of measures aimed at enhancing the security of ships and port facilities. In addition to the creation of the well-known ISPS Code, the conference also included a modification to SOLAS Regulation XI-1/3 to require ships’ identification numbers to be permanently marked in a visible place either on the ship’s hull or superstructure.
The IMO Ship Identification Number is a unique seven-digit number assigned to propelled, seagoing vessels of 100 gross tons and above. The number is assigned by Lloyd’s Register - Fairplay Ltd. on behalf of the IMO. It consists of the three letters IMO followed by seven numbers.
It is important to note that this number is separate and different from your official number. The official number is an internal control number issued by your yacht’s flag administration and cannot be used to replace the IMO number.
gCaptain’s Short Answer: A vessel’s “IMO Number” is the single best way to track and locate history on a ship since each number is unique and is the only identification that remains with a vessel from shipyard to scrapyard.
Links:
- Official IMO Issuance Page
- Pari-MOU - Ship Info and Detentions by IMO Number (Free)
- Look-Up Vessel Information by IMO Number (Registration required)
- USCG Vessel Information by IMO (Hull) Number
- Shipspotters.com Forum Discussion on IMO Numbers
Related Articles:
Captain John Konrad is co-founder of Unofficial Networks and Editor In Chief of this blog. He is a USCG licensed Master Mariner of Unlimited Tonnage and, since graduating from SUNY Maritime College, has sailed a variety of ships from ports around the world.
He currently lives in Morro Bay, California with his wife and two children.
Full Profile: John
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17 responses so far ↓
1 Devon // Aug 7, 2007 at 5:39 am
Interesting data and the IMO numbers certainly make web based research easier.
2 Devon // Aug 7, 2007 at 5:39 am
Interesting data and the IMO numbers certainly make web based research easier.
3 saad salim // Jan 30, 2008 at 2:28 am
hello
I am saad salim and I wont to registr in website
please sent detils on the mail alshaersaad@yahoo.com
thank you for site
4 saad salim // Jan 30, 2008 at 2:40 am
i want full information about sonata imo number 8004521 ship
5 saad salim // Jan 30, 2008 at 3:28 am
hello
I am saad salim and I wont to registr in website
please sent detils on the mail alshaersaad@yahoo.com
thank you for site
6 saad salim // Jan 30, 2008 at 3:40 am
i want full information about sonata imo number 8004521 ship
7 sirius // Feb 17, 2008 at 9:07 pm
this is to acknowledge to the author that .. i m translating this article to my blog admitting where the original sources are.. thanks for ur information
8 sirius // Feb 17, 2008 at 9:07 pm
this is to acknowledge to the author that .. i m translating this article to my blog admitting where the original sources are.. thanks for ur information
9 cap. marof // Apr 19, 2008 at 5:29 pm
pls revert the answering
did the first two digits at left of ship imo .no. reference to the year of ship built. for example
ship imo .no. 9424285.
the first digits 94 reference to ship was built at 1994
10 John // Apr 19, 2008 at 10:05 pm
Marof,
That is not the case. My ship was built in 2000 and its IMO # starts with 92
11 cap. marof // Apr 20, 2008 at 2:29 am
pls revert the answering
did the first two digits at left of ship imo .no. reference to the year of ship built. for example
ship imo .no. 9424285.
the first digits 94 reference to ship was built at 1994
12 John // Apr 20, 2008 at 7:05 am
Marof,
That is not the case. My ship was built in 2000 and its IMO # starts with 92
13 cap. marof // Apr 20, 2008 at 4:35 pm
Att.kind: mr. john
pls request afull details on imo# as flwg:
1- what is the every digit represented
2- how to choosen the 7 digits
thnk yr cooperation
14 cap. marof // Apr 21, 2008 at 1:35 am
Att.kind: mr. john
pls request afull details on imo# as flwg:
1- what is the every digit represented
2- how to choosen the 7 digits
thnk yr cooperation
15 cap/ marof // May 2, 2008 at 5:20 am
Kindly request to know regarding the jordan country on inclution of STCW IMO. white list or still under supervision of MSC.
Tnk for acooperation
cap/ marof
16 cap/ marof // May 2, 2008 at 2:20 pm
Kindly request to know regarding the jordan country on inclution of STCW IMO. white list or still under supervision of MSC.
Tnk for acooperation
cap/ marof
17 nair // Sep 27, 2008 at 12:50 am
please do not bull shit
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