Search for ships by port rotation number
This page is an index of ships by port rotation numbers drawn from the primary records of British shipping prior to 1855.
The registers of British seafarers for the period 1845 to 1854 are held at The National Archives (TNA) and show the person's career at sea, drawn from the crew lists of British ships. The registers use a code made up a port rotation number to identify the ship and a port number for the ship's port of registry. The key to the port numbers is known and this index to the port rotation numbers identifies the ship, so the crew lists can be found.
The crew lists are held at TNA in the series BT 98 in thousands of boxes (pieces) sorted by year, by port of registry and then by ship's name. Without the ship's name, there might be many pieces to search through, each holding up to 100 documents for many different ships.
This search page returns the ship's name with a list of the boxes of crew lists in BT 98 which are likely to hold the crew documents. It also provides links to the FamilySearch films which provide access to images of the documents.
Once the correct document has been found, the matching port rotation number is shown on it, thus completing the loop.
For full details of port rotation numbers, please follow this link:
Port Rotation Numbers
How to search for ships by port rotation number
Enter the ship's port rotation number and select either the port name or number from one of the drop-down lists.
Then click .
Reading the results
The results show the ship's name and any data which has been extracted from BT 98, combined with other sources to provide details like registration entries and tonnages. We show the source of the data and if the main source is BT 98, we provide a link to TNA's catalogue.
Some data not found in BT 98 has been deduced from missing numbers. As explained in the full notes, Pete Owens discovered the underlying link between the Port Rotation numbers and the shipping registers for the port. That means that missing data can be deduced. For example, if port rotation numbers 195 and 199 for Whitby match with register entries 25/1840 and 29/1840, then port rotation number 197 would match with 27/1840, which can be identified from BT 162/19 as the ship Henry. We show the source of that data as 'Deduced from BT 98 and other sources'. We show how confident we are in this interpolation by a percentage, (Q) - 99% is best, down to 60% where there is a gap of twenty records.
We also provide links to other CLIP data for ships of that name. One link is for pre-1855 records; the other is for later years (but bear in mind that the ship may not have been extant by then).
Beware! If you are using data from the seafarers' records, please bear in mind that it is often difficult to read the port rotation numbers. Do consider alternative readings and consider referring to newspaper records which may help to confirm which ships arrived or left around that date.
Using the results
Knowing the name of the ship, it is possible to work out which boxes at TNA might contain documents for the ship. We show that in the lower part of the page.
We use a colour code to show how sure we are that documents will be found, as shown in this table.
Be aware Apart from the years from which we have extracted data, there is no guarantee that documents will be found in any box, especially so where we have deduced the ship's name from other data. For some years, we can be fairly sure that the documents are not in that box, because they were not found there when data was extracted. We can not accept liability for the results of any inaccuracy in our data.
Please remember also that the data refers to the port rotation number - not to the ship's name. For example, if the ship was re-registered at the same port, there may well be documents for her after that date, but with a different port rotation number.
Where we have details of when the ship's registration at that port began and/or ended, we have used that to add comments about the years for which there are likely to be documents. For example, if the ship is shown in BT 162/19 as being re-registered in 1850, we will point out that there may be records for her in later years, but with a different port rotation number.
| Colour codes for crew list sources |
|---|
| Documents have been found in this reference |
| Documents may be found in this reference |
| Documents were not found in this reference for port rotation number nnn |
| Documents will probably not be found in this reference for port rotation number nnn |
There are two link icon buttons against each data item for the document sources:
shows the TNA reference and provides a link to TNA's catalogue.
shows the film reference and provides a link to the images on the FamilySearch site.
Be aware. You need an account with FamilySearch for this to work, and to be working from a FamilySearch centre or a FamilySearch Affiliate Library.
against a references indicates that crew name data from that reference is included in the name index (£) for the 1851 records in BT98 made by Family History Indexes.
Why does the search fail and what other routes might work?
Our data is a 10% sample of the crew documents for the period 1845 to 1854 - all of those for 1851. We are adding data to cover the period up to 1854 for the larger ports and are able to fill many of the gaps using the underlying pattern of the data which Pete Owens discovered.
There are several reasons why a search might fail:
- Our sample may not include data for that year - for example after 1851 for many ports (though we are slowly adding data up to 1854)
- We may not have been able to interpolate reliably between data points. Our limit is a gap of 20 between numbers for data 1845 onwards. For data for ships registered pre-1845 it is generally not possible to interpolate at all. The reason is that some of the earlier registered ships may not have been extant in 1845 when the port rotation numbers started; it is tricky and laborious to find which they were.
- We may have made an error in transcribing the data. We made extensive checks and cross-checks as we transcribed the data and afterwards, but the crew documents are often difficult to read and we are human enough to make mistakes.
- The Victorian clerks made mistakes too, for example in transposing digits. They were good at their jobs, but probably had the same problems that we have in reading their colleagues' writing.
- You may be using port rotation numbers from either pre-1845 or the first half of 1854. They use a different system.
What might work?
It may be possible to find the name of the ship or narrow it down to a few possibilities by looking through the registrations for the port. The ship's port is often fairly easy to identify from the documents. BT 111 data in our ships by port pages
Ships by port
shows ship registrations by port with port rotation number data, if any, shown against each ship.
The data can be sorted by the registration order (which is also the order of the port rotation numbers). Scanning through may reveal entries either side of your target number, with a gap narrow enough to produce just a few possible ship names.
It is also often easy to find the dates when the voyage began and/or ended. Searching the newspaper shipping news may show a match with one of the possibles you have identified.
Of course, this is not easy, but it has been known to work!
Data sources
The data comes from a 10% sample of the crew lists in BT 98 for the period 1845 to 1854 - all of the documents for 1851. Most of the transcription was done using the FamilySearch films, working at FamilySearch Affiliate Libraries.
In parallel with gathering data from the crew lists, CLIP compiled indexes of ships pre-1855. One set is from BT 162/19 which lists ships extant in 1850 and the second is from parts of BT 111 which cover the period from the 1820s to 1855. This data is available separately here:
Ships pre-1855
and
Ships by port
The data from the crew lists was cross-checked during and after transcription by comparing it with data from BT 111 and BT 162, and also against the underlying links to the shipping registers on which the port rotation numbers were based.
Because of this tight cross-checking, the overall accuracy of the transcribed sample data is high - better than 95% - despite the fact that the documents themselves are hard to read and the Victorian clerks made errors (such as typos and confusing the registration dates for a ship). We were able to detect the errors and allow for them, generally by omitting the erroneous data.
Acknowledgements
The Port Rotation Number Project began when Peter Hamersley contacted CLIP in the summer of 2020 suggesting an index to the port rotation numbers. He has worked with us on the hard slog of extracting the data which makes it all work. We have been delighted to work with him in developing what is a major step forward in researching the crew documents held in BT 98.
We are most grateful to Bruno Pappalardo at TNA who has provided valuable support and assistance.
We thank our volunteer transcribers, Robert Holloway, Laura Hamersley and Janine Hamersley in Australia, Maxwell Crockett in NZ and Myfanwy Gate at the National Library of Wales (NLW). The staff of NLW have been most helpful.
James Canney has made helpful suggestions about the way the data is displayed.
Anglesey Archives have provided invaluable assistance by arranging for FamilySearch Affiliate Library status to provide CLIP with access to the records online.