Port rotation numbers

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Port rotation numbers - and the problem

The port rotation numbers were a code used by clerks at the Registry of Shipping and Seamen during the 1840s and 1850s to compile registers of seafarers which are now held at The National Archives (TNA). They were used particularly in the registers for 1845 to 1855 (TNA's series BT 113).

From 1835, masters and owners of ships were legally required to make a written crew agreement which showed a list of the crew. After each voyage or every six months, the documents were returned to the port officials and forwarded to the Registry of Shipping and Seaman in London (and which are now at TNA in series BT 98). The data from the crew documents was used to make up the various registers of seafarers using a numerical code.

The code included the port number which showed the ship's port of registry and the port rotation number, which showed which of the ships from that port the seafarer had been working on.

So the registers of seafarers and the crew lists have survived. The key to the port numbers is known but, unfortunately, the original key to the port rotation numbers has not survived. So there are extensive records of seafarers showing which ships they worked on, but in a code, and also the crew records for the ships, but no way to make the direct connection between them.

For example, a seafarer's record in BT 113 might show a code: M, 456-64-6/51.

Most of it is clear: M means Mate, 64 is the code for London and 6/51 shows that the voyage ended in June 1851.

The missing bit is the 456: that is the port rotation number for a ship registered in London, but there is no key to say what the ship's name was. The crew document could be anywhere in the dozens of boxes of crew lists for London for 1851 in BT 98, each with a hundred or so documents, each with many crew members. Searching those boxes for one seafarer would take some time.

The official position was that 'No index to the port rotation numbers has been found'. That was true, until now...

Using this page

The page can be followed step by step, or you can jump to a step by following one of these links:

Finding the key The numbers game Assigning the port rotation numbers Using the port rotation numbers Recreating the list Using the new index Acknowledgements

Finding the key to the port rotation numbers

CLIP was approached by family historian Peter Hamersley, who has researched crew lists for the period using images of the documents which are available online on Family Search via LDS Church Family History Centres and associated libraries.

Peter was convinced that the port rotation numbers were assigned to individual ships and did not change. He had made up a list of port rotation numbers for his own use and suggested extracting data from the crew documents to compile a modern version of the key to the numbers. That would take some time, but the idea was that the few hundred boxes of crew documents for one year would provide a key which would work for other years as well. However, that depended on the initial assumption being correct.

Peter provided us with some of the data he had extracted for Whitby ships and we compared that with other data which we had from the shipping registers for Whitby. The key was there: the port rotation numbers went in step with the numbering in the shipping registers. So the port rotation number did indeed belong to a particular ship, though with the slight twist that a ship gained a new port rotation number if she was re-registered, even if the new registry was at the same port. So Peter was right.

This link to the shipping registers is significant. It provides the system that must have underlain the allocation of the numbers and that validates what Peter was saying. The link can readily be tested against the data. All checks so far indicate that it works! That being so, it provides a way of checking data extracted from the crew lists and of extrapolating from the extracted data to other ships and other years. A relatively small amount of data extraction would provide the key to most of the seafarers' records.

We explain below exactly how the port rotation numbers were created and used.

We also explain how the 1851 Port Rotation Numbers Project will make a modern equivalent of the clerks' lists which will be available online.

The numbers game

Several different numbers turn up in the records of ships and seafarers - not all of them named consistently, either

We'll need to refer to some of them below, so this list explains what they are:

Port numberNumbers used as a shorthand for ports of registry - for example, London was port 64.
Register numberRegister entries at a port of registry were numbered sequentially, starting at 1 each year. This was used as a way of identfying a ship - for example, Mary, Hull 45/1842.
Port rotation numberNumber allocated to a ship and used as part of a code to identify the ship and her port of registry.
Register ticket numberNumber allocated to a seafarer in the registers of seamen.
Official numberUnique number allocated to each ship after 1855. This was sometimes annotated on earlier shipping registers retrospectively.

How the port rotation numbers were assigned

Figure 1 shows how the port rotation numbers were allocated. The data is fictional.

They started from the shipping registers at the port of registry.

When a ship was registered, a fresh entry was made in the local shipping register. The entries were numbered consecutively, with the register numbers starting again at 1 each year.

That register number was marked on a copy of the register entry which was given to the ship's owner. It formed part of the ship's papers and was proof that the vessel was a British registered ship.

A further copy (transcript) of the register was sent to the Registry of Shipping and Seamen in London.

The port rotation number list was probably compiled from these transcripts. As each new transcript arrived, the clerks added details of the ship (name and register number) to the list of ships for that port and the new entry was allocated the next port rotation number.

The port rotation numbers therefore go in step with the register entries back at the port. The numbers are not identical however, because the register numbers start at 1 again each year.

If a ship was re-registered at another port, it gained a new port rotation number corresponding to the new register entry when the transcript of that arrived in London. That number would be the next available port rotation number for the new port.

The same applied if the ship was re-registered at her existing port (registered de-novo). A new port rotation number was allocated, superseding the old one. Ships could therefore have several port rotation numbers, one for each registration. The reason for doing this is that ship was identified from the crew list by the register number and year (see below) which would be the most recent registration details. Also, it was probably simplest for the clerks just to allocate a new port rotation number, rather than searching back (unreliably) or cross-referencing to the old details.

Similar reasoning was probably why numbers were not re-used when a ship was lost or sold abroad.

The ports of registry also made annual returns of ships registered and it is possible that these returns were used as well.

The remaining question is what was the source for the first lists of port rotation numbers?

The port rotation numbers go in exact sequence with the register numbers from 1846 onwards. Prior to that, they are still linked to the register numbers, but it appears that some ships do not appear in the list of port rotation numbers. That would indicate that the lists were originally compiled in 1845, starting with ships which were still extant at that date. It is possible that the ports annual returns of shipping for 1845 were used to start the list, but unfortunately, only the returns for 1850 have survived and are in BT 162/19.

As we work further into the documents, more details and twists will undoubtedly emerge.

Fig 1: How the port rotation numbers were allocated
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How the port rotation numbers were used

Figure 2 shows how the port rotation numbers were used. The data is fictional.

The port rotation numbers were used to compile the registers of seamen's service. There were various registers - some for seamen and others for officers. These registers have survived and are at TNA in BT 112, BT 113, BT 116, BT 119, BT 120 - some of which are indexes to the other volumes. Records for masters are in BT 115 and BT 124.

The source of their data was the crew lists and agreements which were returned to the Registry of Shipping and Seamen at the end of each voyage or at the end of a half-year. These documents were headed with the name of the ship, her port of registry and her register number and year, together with details of the owner and master and the period that the list covered. Below that was a list of the crew, with their ages, birthplace, previous vessel and the capacity in which they were engaged.

The first task for the clerks was to identify the ship by looking up the port rotation number list for that port and then running down it to find the correct ship, register number and year. Against that they found the port rotation number. That was then copied to the crew list as a part of a code, which was often in this pattern:

Port rotation number-Port number-Date the voyage ended

Once that was done, the crew document was passed to the clerks whose job it was to compile the registers. They had the difficult task of finding the seafarer in the registers - difficult because the seafarer's name was handwritten on the crew list, often badly. On some crew documents, the seafarer's ticket number was shown, which must have been of great assistance to the clerks.

Having found the right seafarer, they then copied the code from the crew list to the register entry for that person.

They then moved on to the next member of the crew and repeated the operation.

Fig 2: How the port rotation numbers were used
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How the port rotation numbers list is being recreated

Figure 3 shows how the port rotation numbers are being recreated. The data is fictional.

Recreating the list of port rotation numbers starts from data extracted from the crew lists in BT 98. Peter Hamersley is working on the documents for 1851. There are 458 boxes of them, from BT 98/2371 to BT 98/2808 with an additional seven boxes of colonial records. Working from films at an LDS Church affiliated library, he is producing a simple list of the names of the ships and the port rotation number written on the documents.

Peter is working on the records for one port at a time. There are several boxes for most ports and many for ports like Liverpool and London. It takes less than one hour per film for an experienced transcriber.

Can you help?

This is going to take some time and we would be glad of any volunteers to help make the transcription for this ground-breaking project. Please get in touch if you visit TNA and sometime have time to spare, or if you have access to Family Search via a LDS Church Family History Centre or an affiliated library.

Please help if you can. Every little helps and everyone will benefit.

CLIP contact details are on the menu bar above. Get in touch and we'll explain how to do it.

In parallel, CLIP is transcribing the data for each port from the annual returns for 1851 in BT 162/19, images of which can be downloaded from TNA for free. We are recording the ship's name, register number and year, and tonnage as shown in the returns. BT 162/19 covers all British ports except London, for which there appear to be no returns, unfortunately. We also have access to other sets of data, such as the early entries in the Appropriation Books, some of which show register numbers and years.

By cross-correlating these data sets, we are able to check the data in the various sets, which is important as these are all hand-written documents and the writing is sometimes not easy to read. Then we can combine the data sets into a composite index, which shows the ship's name, port rotation number, register number and year, and tonnage.

There is a bonus however. Where the port rotation numbers run in strict sequence with the shipping registers, port rotation numbers can be deduced for ships for which there is no BT 98 data, and similarly register numbers and years can be deduced for ships for which those are missing from the other data.

The final bonus is that, following Peter Hamersley's insight, working from the crew lists for one year will produce data which will apply to all years. It will not be all the port rotation numbers, but it will be a substantial proportion of them.

Outcomes of the project

By far the most important output from this project will be the port rotation number index.

This will provide a resource to deal with a long-standing problem, providing a key that has eluded researchers for decades.

Once we have enough data, it will be made avaiable via a search page on this site. Watch this space!

There will be three further outcomes from the project.

  • The data extracted from BT 98 will provide an index to those pieces (boxes) for TNA.
  • The data from BT 162/19 will provide lists of ships extant in 1850 by port, joining the existing CLIP data from MNL for every tenth year from 1860 to 1940.
  • The combined data will also provide the opportunity to create a ships' name index for the period around 1850, with an estimated 30,000+ entries, which will include many small vessels not included in the records of insurance companies such as Lloyds. As with all CLIP data, it will be possible to link it to other sources such as existing register indexes and transcripts.
Fig 3: How the port rotation numbers list is being recreated
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Using the port rotation numbers index

A test version of the new index is now available on this site, but it only contains data from ships registered at the port of Whitby at present. We'll be adding more data steadily.

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The 1851 Port Rotation Numbers Project would not have happened without Peter Hamersley's insight and his work in digging data out of the crew agreements. He has provided the ideas and stimulus which have resulted in a significant breakthrough in solving the mystery of these numbers.

Thank you, Peter.

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