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FAQ
Some of these aren't even AQs, but it's a good place to put this information.
- How do I access your site from my boat?
- This site is for shipping enthusiasts and those interested in the Irish Sea. Please don't use it for navigation! While I try to keep the data on this site as accurate as possible there are errors and time delays which make it unsuitable for anything but shipping hobbyists.
- Can you add faraway port to your website?
 There is little I can do to increase the coverage I have. The AIS signal is limited to line of sight, so I can receive ships out to a range of about 35 miles from Wallasey. Apart from special weather conditions (an inversion), the only way I can pick up ships from further afield is by swapping data with other ShipPlotter users over the Internet.
Coverage of other ports is reliant on enthusiasts to set up their own AIS receivers and so is not complete or continuous. See the map to the right for an indication of the areas covered. The coverage changes hour by hour as some people can only share data in the evenings or at weekends.
If you would like to decode AIS data for your own area then you will need a radio capable of receiving the Marine VHF band: 161.975 and 162.025 MHz with, preferably, an outdoor aerial. The receiver will need a discriminator output (see discriminator.nl) or you can buy a dedicated AIS receiver
(eg NASA AIS engine,
Smart Radio SR161 AIS Receiver,
EasyAIS or
KATAS receivers.
This list is not a recommendation and there are many other receivers available).
Have a look at the ShipPlotter FAQ or contact me and I will try to help.
If you are already receiving AIS data and would like to contribute your data directly to this website, see the question on "How can I contribute?".
I am unable to set up AIS receivers at other ports. My hope is that by raising awareness of AIS through this website, others will take up the hobby and set up their own AIS receivers. If they have ShipPlotter and an Internet connection, then I can share data with them.
- How can I contribute?
- While I am not trying to compete with other community websites, contributions to improving this one are always welcome.
- If you have information or corrections about ships that you feel would be useful to others, email me as ian(at)aisliverpool.org.uk.
- If you have original photographs of ships they can be emailed to ian(at)aisliverpool.org.uk and I will add them to the site along with your name. I cannot accept scanned images because of copyright.
- If you would like to contribute AIS data from ShipPlotter, click on Options->Sharing->Server and add www.aisliverpool.org.uk.
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| Old ShipPlotter |
For ShipPlotter 10.7 and later, set Port 80 |
The 'forward data from server 1 to server 2' box should not be ticked if you are sharing with the COAA server. Please only upload your own AIS data to AISLiverpool.
By convention, ShipPlotter data is not forwarded to other users if your Share ID is a capital letter (A,B,C...Z). I also use this convention, so if your Share ID is a capital letter then your data will not appear on AISLiverpool.
- If you have technical skills and would like to help with design or features of the website, please get in touch with me.
- I live near faraway port, can I set up a similar website?
- Of course! ShipPlotter supports a variety of ways to display AIS data on a website:
- Save and FTP a JPEG image which can be displayed with standard HTML.
- A VBscript can use OLE/COM methods to save the AIS data in a xml file which can be read by Javascript. This is used on my pan & zoom page.
- HTTP POST data to a database which is then read by PHP.
If you'd like help or any of the PHP/MySQL code I've developed on this site for your site just leave a message or contact me through ian(at)aisliverpool.org.uk.
I am not an affiliate of ShipPlotter, just a happy user and the only program I'm familiar with. There are many other programs available for decoding and plotting AIS data.
- What's with the adverts? I thought this site was free.
- The popularity of this website has increased so much that it is getting difficult to continue the growth. When I first set up my webcam, I was amazed to get 20,000 visitors a month, now I have had more than that many pages in a single day. If I do nothing, it may mean the site just crumbles under the load of visitors (See the
Slashdot effect.)
While I continually try to improve this site, there is only so much I can do for free. Even sites offering hit counters start charging if the number of visitors exceed a few thousand a day. Hosting companies offering more advanced features like PHP or databases, start charging commercial rates for the level of traffic I get.
I appreciate that both AIS data and ship photographs are given freely, but I would like to bring sufficient income to cover my broadband and electricity costs. Possibly with some left to help maintain this website and save for future hardware upgrades. All money from adverts will be invested back into this website or donated to good causes. I do not want to make a profit from other peoples hard work.
- Can I copy this site to my hard drive so it would be really quick to use?
- Please don't. There are several hundred megabytes of images on this site (all copyright) and the high load that mirroring programs put on this site make it very slow for all the other users. Also many of the pages are continually updated with the latest information so the copy on your hard drive would soon be out of date.
If you really need a lot of data contact me and I will see what I can do. I may be able to display it in a form that is useful to both you and other people.
Abusers will be banned and hackers are logged and reported.
- I know there's a particular ship out there, why doesn't it appear on your site?
OR why is your AIS data wrong?
OR why is your AIS data out of date?
- AIS is required for ships over 300GT that travel in international waters, so if they never leave the river then they do not need to carry AIS. This applies to the Mersey Ferries, some dredgers, some tugs and all ships under 300GT. For instance, Mersey Mammoth usually operates in the river without AIS, but turns it on if she needs to travel further afield.
Even if a ship is carrying AIS, it does not guarantee she will appear on this website. AIS data is a public radio broadcast, much like BBC Radio 4 is. If nothing is broadcast, the wrong information is broadcast or if interference or bugs corrupt the data, there is little I can do except to wait and hope that the correct data are broadcast again soon. I only receive the AIS data and cannot ask for corrected information to be rebroadcast.
I do have checks that are able to catch some errors or correct some missing information, so the data that appears on this site is not always the same as the broadcast AIS. However, the wrong information is sometimes entered into the on-board AIS units (eg wrong ETA or length in feet instead of meters) and the Maritime and Coastguard Agency do have a scheme to correct such errors (Marine Information Note MIN 231 (M+F)).
- Something doesn't work or looks strange in my browser
- I've written most of this website myself and try to use compliant XML wherever possible, but bugs and mistakes can creap in. The site uses some advanced CSS and JavaScript so I try to test it with Firefox, Internet Explorer V6 and Opera, but I don't have access to all browsers. If there is a mistake contact me and I'll see if I can fix it. I have also registered this site with the Internet Content Rating Association (ICRA) to not have any harmful or offensive material.
- Why did you start this site?
- My original and professional interest is in image processing and I wanted to experiment with a webcam. Most of my view is of other peoples houses, but there is a narrow gap where I can see part of the sea. I ran a webcam for about a year experimenting with motion detection software and slowly gathering a collection of nameless shipping pictures. I was then introduced to AIS as a way of identifying these ships. As my interest in AIS grew, I added more maps and the popularity of my website started to rocket:
| Summary: |
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| Days Logged: |
778 |
| Total Pages: |
19349017 |
| Total Visits: |
2465600 |
| Currently Online: |
77 |
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| Averages: |
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| Daily Pages: |
24870 |
| Daily Visits: |
3169 |
| Pages / Visit: |
7 |
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- Didn't the IMO condemn publishing AIS data on the web?
- Well, yes and no. In December 2004, under Maritime security - AIS ship data, they said that it was
"detrimental to the safety and security of ships and port facilities and was undermining the efforts of the Organization and its Member States to enhance the safety of navigation and security in the international maritime transport sector."
However, in the IMO FAQ on maritime security, they answer the question
Should IMO be worried about the implications of terrorists or criminals using AIS derived information to target vessels?
IMO has taken an action to cover this area of concern, i.e. that operation of AIS in certain sea areas would cause security concern because information broadcasted through AIS could be collected by pirates or terrorists. Because of this concern, the last Assembly in November 2003 adopted resolution A 956(23) Amendments to the Guidelines for the onboard operational use of shipborne automatic identification systems (AIS) resolution A.917(22) which allows ship masters to switch off the AIS in specific areas where threat of attack by pirates or terrorists are imminent.
AIS is the broadcasting device and information will be made available for everyone without any discrimination. That information will be available for the coast safety agencies and authorities and could equally be available for ill-minded people. AIS itself is a tool used in an information collection system and we can not prevent people misusing that information.
However, AIS is also useful for monitoring the situation over any particular sea area by the security authorities within the security system established by those security authorities.
Concern over the security implication of the operation of AIS can only be overcome by tightening the security control measures to be enforced by the coastal security authorities.
This point is clarified by the Maritime Coastguard Agency in Appendix 2 of MGN 298 (M):
- A2.6. AIS is a shipboard broadcast system that acts like a transponder and operates on the VHF maritime band enabling the ship to communicate both with the shore and with other ships. Operation of AIS is a requirement under Chapter V of the amendments to SOLAS 2002. The system allows a ship's location and movements to be monitored on shore and by another suitably equipped ship up to a notional range of 35 miles. A ship with AIS installed is able to display information such as the size, speed and heading of similarly equipped ships within VHF range.
- A2.7. Clearly the risk of having AIS turned on while a ship is transiting through an area known to have a high level of piracy attacks, is that the ship can easily be targeted and located. This is especially the case if 'would be' attackers in the vicinity have been able to obtain their own receiver. Additionally, the advent of open source on-line AIS information has also increased the 'visibility' of ships using AIS. While it is not recommended under ISPS Regulations to turn AIS off as this may affect the safety of the ship, if a situation arises where the Master of the Ship feels under threat by keeping AIS turned on, then UK flagged ships should conduct a risk assessment. If the assessment determines that the threat to the security of the ship is greater than the threat to safety, then the Master should turn AIS off while the threat remains present. This however may not be the position of other Flag States and Masters and crew of ships should establish their own policy on AIS use in such scenarios.
- Why all the different types of size information?
- Part of the AIS information includes the ship's size (length, width
(beam) and draught) but for many (around 1 in 8) ships this information is
either not entered or wrong. For instance zero or entered in feet instead of
meters.
The standard international measurement of a ship's size under the
Universal Tonnage Measurement System (UMS), defined by the 1969 Tonnage
Regulations, is the Gross Ton (GT). The 'ton' in gross tonnage is not a
measure of weight but of volume (2.78 cubic meters) and is more closely
related to the old English word 'tun' used as a measure of wine. It must not
be written as 'tonne' which is an internationally accepted unit (under the
SI system) of weight.
However, volume (GT) is only a useful guide for certain types of vessel,
mainly conventional cargo ships and passenger ships. For tankers and bulk
carriers, lifting capacity is a more useful guide and this is measured by
Deadweight Tonnage (dwt) in tonnes of weight.
So as you can see the size of ship can be measured in a variety of ways.
When possible, I try to use GT even though it is not broadcast on AIS as
this information is most readily available from other sources. If GT is not
available, I use the broadcast dimensions from AIS.
- What is your webcam pointed at?
- In the distance you can see the Lennox rig.
The Lennox gas and oil rig.
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Gascam looks along the entrance to the Mersey.
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The Lennox rig lies about 14 miles (23km) away.
View of Queens Channel and Crosby.
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